APPLICATION SCHEME BOOK

Transcription

1 PPLIIO SHM OOK Global Headquarters 9048 Meridian ircle, orth anton, OH Phone Fax oll Free

2 PPLIIO SHMS - Introduction In order to lay out complicated interlock schemes, it is necessary to understand the simplest applications. On this page, the bic concepts of interlocking are outlined and discussed. Interlocking a Single Unit in One Interlocking wo Units in wo s If it is desired to secure a device in the open position, an interlock is used in Fig. 1. he possession of the key indicates Fig. 1 Fig. 2 that the device is in the open position and is locked by the extension of the interlock bolt. hen the key is inserted in the lock and turned to withdraw the interlock bolt, the device is free to operate to the closed position and the key is held in the lock. hen a device is to be locked only in the closed position an interlock is used shown in Fig. 2. he possession of the key indicates that the device is locked in the closed position, the interlock bolt h been extended to remove the key. hen the key is inserted in the lock and turned to withdraw the interlock bolt, the device is free to operate to the open position and the key is held in the lock. Interlocking a Single Unit in wo s wo methods are used in interlocking a device in both open and closed position. he first method requires only one interlock shown in Fig. 3. he interlock bolt is extended in both the open and closed positions. his is accomplished with two recesses in the device that is being interlocked - each coinciding with the locking bolt in one position. he other method for locking in both the open and closed positions requires two interlocks show n in Fig. 4. Possession of key -1 indicates that the device is locked open. Possession of key -2 indicates that the device is locked closed. he device is shown normally open; therefore, key -1 is free and the L-O interlock bolt is extended into its recess provided in the movable member while key -2 is held and the L- interlock bolt is withdrawn. o close the device, insert key -1 in the L-O lock and turn to withdraw bolt of L-O interlock, which permits the device to be operated. ow the device can be moved to the closed position. Key -2 can be turned to extend the bolt of the L- interlock into its recess, which locks the device in the closed position. 1-1 Fig. 4. his relees Key -2 from the L- interlock. Meanwhile, key -1 is held in the L-O interlock since its withdrawn locking bolt cannot be extended. his method is used more often than the single two-position interlock shown in Fig. 3, due to its adaptability to sequence operations. lso, the possession of key -1 or -2 indicates that the device is locked open or locked closed, respectively. Sequence Interlocking 2 ith the fundamentals developed above, it is quite simple to extend the application to the interlocking of two or more devices in a desired sequence. 1-1 L-O- Fig. 3 he possession of the key indicates that the interlock bolt is extended and that the device is locked either in the open or closed position. Furthermore, the device cannot be operated until the key is inserted and turned in the lock to withdraw the locking bolt. he key cannot be removed from the lock in an intermediate position, but in the fully open or closed positions only. However, in this application, possession of the key gives no indication to whether the device is locked closed or open Fig. 5 wo devices are shown in Fig. 5. In operation they are not closed at the same time. ith the interlocks arranged shown, only one key is required in the interlocking system. oth devices are shown open; therefore, the key is free. o close any one device, the key is inserted and turned in that particular lock to withdraw the interlock bolt. he key is held in this lock until the device is again locked open. his simple interlocking sequence lends itself to a multitude of applications. he procedure is the same for two devices, neither of which is to be opened at the same time.

3 Legend\Symbols -1, -2, -3 evice normally open. evice normally closed. irection of key transfer. Key interchange number. ccess door interlock (etachable latch) ype, M or Y. ccess door interlock Multi-cylinder (etachable latch) ype or M. Interlock with auxiliary switch, 2 make - 2 break, ype SS Interlock with key held. evice in position shown. Interlock with key removed. evice in position shown. ransfer interlock, ype. Interlock with auxiliary switch, 3 make - 3 break, ype SSS L-O L-O Interlock used to lock device open. (with key removed) Interlock used to lock device open. (with key held) ransfer interlock, ype. 3 cylinder Interlock with auxiliary switch ype K Key releed after time delay. L- Interlock used to lock device closed. (with key removed) ransfer interlock, ype. 5 cylinder M ime-delay key relee unit Initiating lock. L- L-O- Interlock used to lock device closed. (with key held) Interlock used to lock device open and closed. Multi-lock interlock. Interlock with an apartment lock. (ccepts one of two keys) 3 Padlock ype P Key Interchange number (showing key held). Interlock with auxiliary switch, 1 make - 1 break, ype S Solenoid key relee unit. Key releed when solenoid is, energized. wo key Solenoid key relee unit. Key releed when solenoid is, energized. Initiating key Key releed when solenoid is energized Key Removable s he or next to the interlock symbol indicates the position of the interlock bolt when the key is removable, = xtended, = ithdrawn. For more information regarding key removable positions plee reference the technical paper How an Individual Key Interlock Operates on our website (lick on ''ustomer Portal", "ownloads", and "Manuals & echnical Papers" then click on How an Individual Key Interlock Operates ). Refer also to the vailable Options on the interlock data sheets and to columns 8 and 9 on either Interlock Ordering Guide (rs or 316 Stainless).

4 able Of ontents Purpose of Interlocking Scheme# Function Switch and reaker Scheme #1 Prevents opening of switch when breaker is closed. Scheme #2 Prevents operation of switch when breaker is closed. Permits re-closing the breaker for servicing when switch is locked open. Scheme #3 Prevents operation of switch when breaker is closed. ircuit cannot be cleared until proper supervisory key is obtained. Grounding Switch with Main Switch Scheme #4 Prevents closing of grounding switch when main switch is closed, and vice versa. Isolating Switches and reaker Scheme #5 Prevents operation of disconnect when breaker is closed. Prevents opening fuse compartment door when disconnect is closed. Scheme #6 Prevents operation of disconnect when any or all of a group of breakers are closed. Operates through transfer interlock, no sequence is required for breaker closing. Scheme #7 Prevents operation of disconnect when any or all of a group of breakers are closed. reakers operated in prearranged sequence. Scheme #8 Prevents operation of disconnects when breaker is closed. Permits servicing of breaker when disconnects are locked open. Scheme #9 Prevents operation of disconnects when breaker is closed, and prevents access to breaker compartment with disconnects closed. Isolating Switches and reaker or Regulator with y-ps Switch Scheme #10 Prevents operation of breaker disconnects and by-ps disconnect under load. Provides for closing of by-ps disconnect before breaker circuit is opened, or permits circuit breaker to be opened with by-ps disconnect remaining open. Scheme #10 Prevents operation of voltage regulator disconnects and by-ps disconnect under load. Permits by-ps disconnect to operate only when regulator is in neutral position. Permits isolating regulator for servicing. Prevent Paralleling of Lines Scheme #11 Prevents paralleling of two lines - single load, fed from either source. Scheme #12 Prevents paralleling of two lines - single load, fed from either source - breaker on load side. Scheme #13 Prevents paralleling of two lines - two loads, fed from either source (one tie breaker) Scheme #14 Prevents paralleling of two lines - two loads, fed from either source (one tie breaker). Prevents operation of switch when breaker is closed (on either source). Scheme #15 Prevents paralleling of two lines - two loads fed from either source (one tie breaker). Prevents operation (open or closed) of disconnect when breaker is closed (on either source). Prevents access to fuses when disconnects and breakers are closed. Scheme #16 Prevents paralleling of three lines - three loads, fed from any source (two tie breakers). Scheme #17 Prevents paralleling of four lines - four loads fed from any source (three tie breakers) Scheme #17 Prevents paralleling of four lines - four loads fed from any source (three tie breakers). lso prevents opening of rear access doors when breakers are energized. Scheme #18 Prevents paralleling of three lines - three loads fed from any source (three tie breakers). Scheme #19 Prevents paralleling of four lines - four leads fed from any source (four tie breakers). Scheme #20 Prevents paralleling of three power sources through a common tie bus not normally in service. Permits feeding any load bus from a second power source through the tie bus. Permits one power source to supply all three load buses through the tie bus. Scheme #21 Prevents paralleling three power sources through a common tie bus not normally in service. Permits feeding any load bus from a second power source through the tie bus only when authorized by a supervisor. Permits one power source to supply all three load buses through the tie bus only when authorized by a supervisor. Scheme #22 Prevents paralleling two incoming primary sources through primary tie bus disconnect. Prevents operation (open or closed) of the disconnects under load. Permits one power source to supply both loads through tie bus. Scheme #23 Prevents paralleling of two incoming primary sources through the primary tie bus disconnect or secondary tie bus breaker. Prevents operation (open or closed) of disconnects under load. Permits one power source to supply both loads through either the primary or secondary tie bus. Scheme #24 Prevents paralleling of two incoming primary sources. Prevents operation (open or closed) of disconnects under load. Permits the isolating of breakers for servicing. Permits one power source to supply both loads through tie bus. Interrupter Switch Scheme #25 Prevents opening fuse compartment door when the interrupter switch is closed. Prevents closing interrupter switch until fuse compartment door is locked closed. Scheme #26 Prevents operation (open or closed) of interrupter switch when breaker is closed. Permits the breaker to be serviced and operated while the interrupter switch is locked open. able of ontents ontinued ext Page

5 able Of ontents Purpose of Interlocking Scheme# Function Interrupter Switch Scheme #27 Prevents operation (open or closed) of interrupter switch when breaker is closed. Prevents opening fuse compartment door when Scheme #28 Scheme #29 Scheme #30 Scheme #31 Scheme #32 interrupter switch is closed. Prevents closing interrupter switch until fuse compartment door is locked closed. Permits the breaker to be serviced and operated while the interrupter switch is locked open. Prevents dropping load when shifting from one source to the other. Prevents opening both interrupter switches at the same time. Permits both interrupter switches to be closed at the same time. Prevents paralleling two lines - requires dropping load when shifting from one source to the other. Prevents closing both interrupter switches at the same time. Permits both interrupter switches to be opened at the same time. Prevents paralleling two lines - requires dropping load when shifting from one source to the other. Prevents closing both interrupter switches at the same time. Permits both interrupter switches to be open at the same time. Prevents operation (open or closed) of either interrupter switch when breaker is closed. Permits the breaker to be serviced and operated while both interrupter switches are locked open. Prevents operation (closed, open or closed) of a three position interrupter switch when the breaker is closed. Permits the breaker to be serviced and operated while the interrupter switch is locked open. Prevents operation (closed, open or closed) of a three position interrupter switch when the breaker is closed. Prevents opening fuse compartment door when the interrupter switch is closed. Prevents closing interrupter switch until fuse compartment door is locked closed. Permits the breaker to be serviced and operated while the interrupter switch is locked open. Motor or Machinery Guard Scheme #33 Prevents opening of guard when motor circuit is closed. Guard may be a door or fence gate that prevents access to moving parts, belts, cutters, or any dangerous equipment. Motor or Machinery Guard with ime elay Scheme #34 Prevents opening of guard (or door) for a predetermined time after removal of power (from motor, centrifuge, condensers, etc.) reakers and Generators Scheme #35 Prevents paralleling of two lines - two loads, fed from either source (one tie breaker). llows switching loads to a generator. Scheme #35 Prevents closing generator breaker when main breaker is closed. Scheme #36 Prevents paralleling of two lines - two loads, fed from either source (one tie breaker). llows switching loads to two generators. apacitor ank ccess Scheme #37 Prevents access to capacitor bank enclosure until capacitors have been grounded and discharged. Scheme #38 Prevents access to capacitor bank enclosure until capacitors have been grounded and discharged - utilizing a ime elay Key Relee Unit (KRU). Uninterrupted Power Sources Scheme #39 Prevents improper maintenance byps of UPS equipment. Scheme #40 Prevents improper maintenance byps of UPS equipment. Precipitator ccess Scheme #41 Prevents access to an electrostatic precipitator, scrubber, or baghouse until all power supplies have been de-energized and properly grounded. Scheme #42 o allow operation of dual output transformer rectifiers with one field removed from service and to prevent opening any access doors of an electrostatic precipitator until all power supplies are de-energized and properly grounded. Scheme #42 o allow operation of dual output transformer rectifiers with one field removed from service and to prevent opening any access doors of an electrostatic precipitator until all power supplies are de-energized and properly grounded. Scheme #42 o allow operation of dual output transformer rectifiers with one field removed from service and to prevent opening any access doors of an electrostatic precipitator until all power supplies are de-energized and properly grounded. able of ontents ontinued ext Page

6 able Of ontents Purpose of Interlocking Scheme# Function ccess Scheme #43 Prevents opening any rectifier enclosure door while the rectifier is operating. Scheme #43 Prevents opening any rectifier enclosure door while the rectifier is operating. Scheme #44 Prevents opening any rectifier enclosure door while the rectifier is operating. Scheme #45 Prevents opening any rectifier enclosure door while the rectifier is operating and prevents opening the negative disconnect switch under load. Scheme #45 Prevents opening any rectifier enclosure door while the rectifier is operating and prevents opening the negative disconnect switch under load.

7 Scheme 1 o prevent opening of switch when breaker is closed. Switch and breaker are in closed position. Key -1 is held in breaker interlock. 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key - 1 is now free. 3. Insert key -1 in L- interlock on switch and turn to unlock. 4. Open switch. Key -1 is now held. Scheme 2-1 o prevent operation of switch when breaker is closed. Permits reclosing of breaker for servicing when switch is locked open. 1 Scheme 3 o prevent operation of switch when breaker is closed. ircuit cannot be cleared until proper supervisory key is obtained. -1 L-O- reaker and switch shown closed. Key -1 held in breaker interlock. Key -2 retained by supervisor. 1. Obtain key -2 from supervisor. 2. Open breaker. 3. Insert key -2 in L-O interlock on breaker and turn key -1 to lock open. key -2 is now held and key -1 is free. 4. Insert key -1 in L-O- interlock on switch and turn to unlock. 5. Open switch. 6. urn key -1 in L-O- interlock on switch to lock open. Key -1 is now free. 7. Return key -1 to breaker interlock and unlock for operation during servicing period SUPRVISORY KY -1 1 L-O- Scheme 4 o prevent closing of grounding switch when main switch is closed, and vice versa L-O- 1-1 Switch and breaker are in closed position. Key -1 is held in breaker interlock. 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key - 1 is now free. 3. Insert key -1 in L-O- interlock on switch and turn to unlock. 4. Open switch. Key -1 is now held. 5. urn key -1 in L-O- interlock on switch to lock open. Key -1 is now free. 6. Return Key -1 to breaker interlock and unlock for operation during servicing period. Main switch shown closed and grounding switch shown open. Key -1 is held in main switch interlock. 1. Open main switch. 2. urn key -1 in L-O interlock on main switch to lock open. Key -1 is now free. 3. Insert Key -1 in L-O interlock on grounding switch and turn to unlock. Key -1 is now held. 4. lose grounding switch.

8 Scheme 5 o prevent operation of disconnect switch when breaker is closed. o prevent opening fuse compartment door when the disconnect switch is closed L-O- reaker, fuse compartment door and disconnect switch are shown in closed positions. Key -1 is held in breaker interlock and key -2 is held in disconnect interlock. o service breaker: 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock breaker open. Key -1 is now free. 3. Insert key -1 in L-O- interlock on disconnecting switch and turn to unlock. Key -1 is now held. 4. Open disconnect. 5. urn key -1 in L-O- interlock on disconnect switch to lock open. Key -1 is now free. 6. Return key -1 to breaker interlock and unlock for operation of breaker during servicing. o open fuse compartment door: 1. Proceed from normal position with operations in 1 through 4 above. 2. urn key -2 in L-O interlock on disconnect switch to lock open. Key -2 is now free. 3. Insert key -2 in L- interlock on fuse compartment door and turn to unlock. Key -2 is now held. 4. Open fuse compartment door. Scheme 6 o prevent operation of disconnect switch when breakers,, and are closed. reakers may be opened in any sequence. O: lectrical circuit is equivalent of Scheme L-O isconnect and breakers,, and are shown in closed position. Key -1 is held in transfer interlock. Keys -2, -3, -4 and -5 are held in interlocks on breaker,, and. 1. Open breakers,, and. 2. urn key in L-O interlock on each breaker,, and to lock breakers open. Keys -2, -3, -4 and -5 are now free. 3. Insert keys -2, -3, -4 and -5 in transfer interlock. 4. urn key -1 in transfer interlock. Key -1 is now free. Keys - 2, -3, -4 and -5 are now held. 5. Insert key -1 in L-O- interlock on disconnect and turn to unlock. Key -1 is now held. 6. Open disconnect. 7. urn key -1 in L-O- interlock on disconnect to lock open. Key -1 is now free. 8. Insert key -1 in transfer interlock and turn. Key -1 is now held, Keys -2, -3, -4 and -5 are now free. 9. Return keys -2, -3, -4 and -5, desired, to breaker interlocks and unlock for operation during servicing.

9 Scheme 7 o prevent operation of disconnect switch when breakers,, and are closed. reakers must be opened in pre-arranged sequence. Scheme 8 o prevent operation of disconnects and when breaker is closed. o permit servicing of breaker when disconnects are locked open. O: lectrical circuit is equivalent of Scheme L-O- 5 SUPRVISORY KY isconnect and breakers,, and are shown in closed position. Key -1 is held in breaker interlock, key -2 is held in breaker interlock, key -3 is held in breaker interlock and key -4 is held in breaker interlock. Key -5 is held free in breaker interlock or is retained by supervisor. 1. Obtain key -5 from supervisor. 2. Open breaker. 3. Insert key -5 in L-O interlock on breaker and turn key -4 to lock open. Key -5 is now held. Key -4 is now free. 4. Open breaker. 5. Insert key -4 in L-O interlock on breaker and turn key -3 to lock open. key -4 is now held. key -3 is now free. 6. Open breaker. 7. Insert key -3 in L-O interlock on breaker and turn key -2 to lock open. Key -3 is now held. Key -2 is now free. 8. Open breaker. 9. Insert key -2 in L-O interlock on breaker and turn key -1 to lock open. Key -2 is now held. Key -1 is now free. 10. Insert key -1 in L-O- interlock on disconnect and turn to unlock. Key -1 is now held. 11. Open disconnect. 12. urn key -1 in L-O- interlock on disconnect to lock open. Key -1 is now free. 13. Insert key -1 in L-O interlock on breaker and turn to unlock. Key -1 is now held and key -2 is now free. 14. reaker may now be operated for servicing. 15. Insert key -2 in L-O interlock on breaker and turn to unlock. Key -2 is now held and Key -3 is now free. 16. reaker may now be operated for servicing. 17. Insert key -3 in L-O interlock on breaker and turn to unlock. Key -3 is now held and key -4 is now free. 18. reaker may now be operated for servicing. 19. Insert key -4 in L-O interlock on breaker and turn to unlock. Key -4 is now held and supervisor Key -5 is now free. 20. reaker may now be operated for servicing. reaker and disconnects and are shown closed. One key -1 is held in breaker L-O interlock and the other key -1 is held in L-O interlock on disconnect. Key -2 is held in L-O interlock on disconnect. 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L- interlock on disconnect and turn to unlock. Key -1 is now held. 4. Open disconnect. 5. urn key -2 in L-O interlock on disconnect to lock open. Key -2 is now free. 6. Insert key -2 in L- interlock on disconnect and turn to unlock. Key -2 is now held. 7. Open disconnect. 8. urn key -1 in L-O interlock on disconnect to lock open. Key -1 is now free. 9. Insert key -1 in breaker L-O interlock and turn to unlock for operation during servicing.

10 Scheme 9 o prevent operation of disconnects and with breaker closed. o prevent access to breaker compartment with disconnects closed isconnects and, breaker, and door are normally closed. Keys -1 are held in L-O interlock on breaker and L-O interlock on disconnect. Key -2 is held in the L-O interlock on disconnect. Key -3 is held in L-O interlock on disconnect. 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L- interlock on disconnect and turn to unlock. Key -1 is now held. 4. Open disconnect. 5. urn key -2 in L-O interlock on disconnect to lock open. Key -2 is now free. 6. Insert key -2 in L- interlock on disconnect and turn to unlock. Key -2 is now held. 7. Open disconnect. 8. urn keys -1 and -3 in L-O interlock on disconnect to lock open. Keys -1 and -3 are now free. 9. Insert key -1 in breaker L-O interlock and turn to unlock for operation during servicing. 10. Insert key -3 in L- interlock (type ) on compartment door and turn to unlock. Key -3 is now held. 11. Open compartment door to service breaker. Scheme 10 o prevent operation of disconnects and and by-ps disconnect under load. Provides for closing of by-ps disconnect before breaker circuit is opened, or permits breaker circuit to be opened with by-ps disconnect remaining open. isconnects and and breaker normally closed. y-ps disconnect normally open. Keys -1, -2, and -4 normally held in locks indicated. Key -3 normally free. -4 L-O o transfer load from breaker and disconnects to by-ps switch: 1. Obtain key -3 which is free and insures that both disconnects and are locked closed. 2. Insert key -3 in L- interlock on breaker and turn to lock closed. Key -3 is held and key -4 is now free. 3. Insert key -4 in L-O- interlock on by-ps disconnect and turn to unlock. Key -4 is now held. 4. lose by-ps disconnect. 5. urn key -4 in L-O- interlock on by-ps disconnect to lock closed. Key -4 is now free. 6. Insert key -4 in L- interlock on breaker and turn to unlock. Key -4 is held and key -3 is now free. 7. Open breaker. 8. urn key -1 in L-O interlock on breaker to lock open. Key - 1 is now free. 9. Insert keys -1 and -3 in L- interlock on disconnect and turn to unlock. Keys -1 and -3 are now held. 10. Open disconnect. 11. urn key -2 in L-O interlock on disconnect to lock open. Key -2 is now free. 12. Insert key -2 in L- interlock on disconnect and turn to unlock. Key -2 is now held. 13. Open disconnect. 14. urn key -1 in L-O interlock on disconnect to lock open. Key -1 is now free. 15. Insert key -1 in L-O interlock on breaker and turn to unlock to permit operation during servicing. o open disconnects and and breaker, leaving by-ps disconnect open: 1. Proceed from normal position with operations in 7 to 15 above.

11 Scheme 10 o prevent operation of disconnect and and by-ps disconnect under load. Permits by-ps disconnect to operate only when regulator is in neutral position. Permits isolating regulator for servicing. Scheme 11 o prevent paralleling of lines and. Single load, fed from either source RGULOR isconnect shown closed and disconnect shown open. Key -1 is held in disconnect interlock L Open switch. 2. urn key -1 in L-O interlock on switch to lock open. Key -1 is now free. 3. Insert key -1 in L-O interlock on switch and turn to unlock. Key -1 is now held. 4. lose switch. Reverse sequence to restore service through switch. isconnects and are normally closed. Regulator is normally in operation. y-ps disconnect is normally open. One key -1 is held in regulator L- (locked neutral) interlock and the second key -1 is held in L-O interlock on disconnect. Key -2 is held in L- interlock on disconnect. Key -3 is held in L-O interlock on disconnect. 1. Operate regulator to neutral position. 2. urn key -1 in L- interlock on regulator to lock in neutral position. Key -1 is now free. 3. Insert key -1 in L-O interlock on by-ps disconnect and turn to unlock. Key -1 is now held. 4. lose by-ps disconnect. 5. urn key -2 in L- interlock on by-ps disconnect to lock closed. Key -2 is now free. 6. Insert key -2 in L- interlock on disconnect and turn to unlock. Key -2 is now held. 7. Open disconnect. 8. urn key -3 in L-O interlock on disconnect to lock open. Key -3 is now free. 9. Insert key -3 in L- interlock on disconnect and turn to unlock. Key -3 is now held. 10. Open disconnect. 11. urn key -1 in L-O interlock on disconnect to lock open. Key -1 is now free. 12. Insert key -1 in regulator L- interlock and turn to unlock. his permits regulator to be operated during inspection and servicing.

12 Scheme 12 o prevent paralleling of lines and. Single load, fed from either source. o prevent operation of disconnect switches and when breaker is closed. 3. Insert key -1 in L-O- interlock on disconnect and turn to unlock. Key -1 is now held. 4. Open disconnect. 5. urn key -1 in L-O- interlock on disconnect to lock open. Key -1 is now free. 6. Return key -1 to breaker interlock and unlock for operation of breaker during servicing. o transfer load from line to line : 2 reaker and disconnect are shown in closed position. isconnect is shown in open position. Key -1 is held in breaker interlock. Key - 2 is held in L-O interlock on disconnect. o service breaker: -1-1 L-O- 1 L-O Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L-O- interlock on disconnect and turn to unlock. Key -1 is now held. 4. Open disconnect. 5. urn key -1 in L-O- interlock and key -2 in L-O interlock on disconnect to lock open. Keys -1 and -2 are now free. 6. Insert key -1 in L-O- interlock on disconnect and turn to unlock. Key -1 is now held. 7. Insert key -2 in L-O interlock on disconnect and turn to unlock. Key -2 is now held. 8. lose disconnect. 9. urn key -1 in L-O- interlock on disconnect to lock closed. Key -1 is now free. 10. Insert key -1 in breaker interlock and turn to unlock. Key -1 is now held. 11. lose breaker. Reverse sequence to restore service through line. Scheme 13 o prevent paralleling of lines and. wo loads, fed from either source. reaker is closed to supply load M. reaker is closed to supply load. ie-breaker is open. Keys -1 are held in interlocks on both breakers and. ie-breaker cannot be closed unless either or is locked open. o transfer load to breaker : 1. Open breaker 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L-O interlock on tie-breaker and turn to unlock. Key -1 is now held. 4. lose tie-breaker. M Load M can be supplied through breaker in a similar manner.

13 Scheme 14 Scheme 15 - (ontinued) o prevent paralleling of lines and. wo loads, fed from either source (one tie-breaker). o prevent operation of disconnect switch when breaker is closed. o prevent operation of disconnect switch when breaker is closed L-O L-O- L-O- L-O M Scheme 15 o prevent paralleling of lines and. wo loads, fed from either source (one tie-breaker). o prevent operation of disconnect when breaker is closed. o prevent operation of disconnect switch when breaker is closed. o prevent opening fuse compartment door when the sociated disconnects or and breakers and are closed. isconnect switches and and breakers and are closed. reaker closed to supply load M. reaker closed to supply load. iebreaker is open. Keys -1 and -2 are held in interlock on breaker. Keys -1 and -3 are held in interlock on breaker. ie-breaker cannot be closed until either breaker or is locked open. o transfer load to breaker : 3 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Keys - 1 and -3 are now free. 3. Insert key -1 in L-O interlock on tie-breaker and turn to unlock. Key -1 is now held. 4. lose tie-breaker. Reverse sequence to restore service through breaker. Load M can be supplied through breaker in a similar manner. o service breaker : 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Keys - 1 and -3 are now free. 3. Insert key -3 in L-O- interlock on disconnect and turn to unlock. Key -3 is now held. 4. Open disconnect. 5. urn key -3 in L-O- interlock on disconnect to lock open. Key -3 is now free. 6. Return key -3 to L-O interlock on breaker and unlock for operation of breaker during servicing. reaker can be serviced in a similar manner. 2 M isconnect switch and breaker are closed to supply load M. isconnect switch and breaker are closed to supply load. ie-breaker is open. Keys -1 and -2 are held in interlock on breaker. Key -3 is held in L-O interlock on disconnect. Keys -1 and -4 are held in interlock on breaker. Key -5 is held in L-O interlock on disconnect. ie-breaker cannot be closed until either breaker or is locked open. o transfer load to breaker, proceed follows: 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Keys -1 and -4 are now free. 3. Insert key -1 in L-O interlock on tie-breaker and turn to unlock. Key -1 is now held. 4. lose tie-breaker. Reverse sequence to restore service through breaker. Load M can be supplied through breaker in a similar manner. o service breaker, proceed follows: 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Keys -1 and -4 are now free. 3. Insert key -4 in L-O- interlock on disconnect and turn to unlock. Key -4 is now held. 4. Open disconnect. 5. urn key -4 in L-O- interlock on disconnect to lock open. Key -4 is now free. 6. Return key -4 to L-O interlock on breaker and unlock for operation of breaker during servicing. reaker can be serviced in a similar manner. o enter fuse compartment on line, proceed follows: 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Keys -1 and -4 are now free. 3. Insert key -4 in L-O- interlock on disconnect and turn to unlock. Key -4 is now held. 4. Open disconnect. 5. urn key -4 in L-O- interlock on disconnect to lock open. Key -4 is now free. 6. urn key -5 in L-O interlock on disconnect to lock open. Key -5 is now free. 7. Insert keys -4 and -5 in L- interlock on fuse compartment door and turn to unlock. Keys -4 and -5 are now held. 8. Open fuse compartment door. Fuse compartment on line can be entered in a similar manner.

14 Scheme 16 o prevent paralleling of lines,, and. hree loads, fed from any source (two tie-breakers). ie-breaker interlock h a mter or apartment lock and can be unlocked for operation with either keys -1 or -1. ie-breaker h a mter or apartment lock and can be unlocked for operation with either keys -1 or o transfer load M from reaker to breaker : 1. Open breaker 2. urn key -1 in L-O interlock on breaker to lock open. Key - 1 is now free. 3. Insert Key -1 in L-O interlock on tie-breaker and turn to unlock. Key -1 is now held. 4. lose tie-breaker. Reverse sequence to restore service through breaker. M reaker is closed to supply load M. reaker is closed to supply load. reaker is closed to supply load P. Keys -1, -1, and -1 are held in L-O interlocks of breakers,, and. ie-breakers and are locked open. P o transfer load M and from breakers and to breaker : 1. lose tie-breaker above. 2. urn key -1 in L-O interlock on breaker to lock open. Key - 1 is now free. 3. Insert key -1 in L-O interlock on tie-breaker and turn to unlock. Key -1 is now held. 4. lose tie-breaker. Reverse sequence to restore service (M and through breakers and ). ny of the loads M,, or P can be transferred from its own supply to any adjacent supply ote: his symbol represents an interlock with an apartment lock. n apartment lock is a single cylinder that will accept two different keys - but only one key at a time. Scheme 17 o prevent paralleling lines,,, and. Four loads, fed from any source (three tie-breakers) o transfer load M from breaker to breaker : 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L-O interlock on tie-breaker and turn to unlock. Key -1 is now held. 4. lose tie-breaker. Reverse sequence to restore service through breaker. o transfer load M and from breaker and to breaker : M reaker is closed to supply load M. reaker is closed to supply load. reaker is closed to supply load P. reaker is closed to supply load R. Keys -1, -1, -1, and -1 are held in L-O interlocks of breakers,,, and. reakers, F and G are locked open. reaker interlock h a mter or apartment lock and can be unlocked for operation with either key -1 or -1. reaker F interlock h a mter or apartment lock and can be unlocked for operation with either key -1 or -1. reaker G interlock h a mter or apartment lock and can be unlocked for operation with either key -1 or -1. F P G R 1. lose tie-breaker above. 2. Open breaker. 3. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 4. Insert key -1 in L-O interlock on tie-breaker F and turn to unlock. Key -1 is now held. 5. lose tie-breaker F. Reverse sequence to restore service (M and ) through breakers and. o transfer load R from breaker to breaker : 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L-O interlock on tie-breaker G and turn to unlock. Key -1 is now held. 4. lose tie-breaker G. Reverse sequence to restore service through breaker. ny of the loads M,, P, or R can be transferred from its own supply to any adjacent supply ote: his symbol represents an interlock with an apartment lock. n apartment lock is a single cylinder that will accept two different keys - but only one key at a time.

15 Scheme 17 o prevent paralleling lines,,, and. o prevent opening rear access doors when breakers are energized. SS OOR #1 SS OOR #2 SS OOR #3 SS OOR #4 SS OOR #7 K-1 K-2 K-3 K-4 K-5 K-6 K-7 K-8 K-9 K 3 SS OOR #5 SS OOR #6 K 6 K 9 SS OOR #8 SS OOR #9 ll loads can be transferred described in scheme 17. o open rear access doors K-1, K-2, and K-3: 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Open breaker. 4. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 5. Insert key -1 and -1 in transfer interlock. 6. urn key -1 in transfer interlock. Keys K-1, K-2, and K- 3 are now free. Keys -1 and -1 are now held. 7. Insert keys K-1, K-2, and K-3 in their respective rear access door interlocks and turn to unlock. Keys K-1, K-2, and K-3 are now held. 8. Open the rear access doors. K 2 K 1 K 5 K 8 K 4 K F G o open rear access doors K-4, K-5 and K-6 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Open breaker. 4. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 5. Insert key -1 and -1 in transfer interlock. 6. urn key -1 in transfer interlock. Keys K-4, K-5, and K- 6 are now free. Keys -1 and -1 are now held. 7. Insert keys K-4, K-5, and K-6 in their respective rear access door interlocks and turn to unlock. Keys K-4, K-5, and K-6 are now held. 8. Open the rear access doors M reakers,,, and are closed to supply their respective loads. Keys -1, -1, -1, and -1 are held in L-O interlocks of breakers,,, and. ie-reakers, F, and G are locked open. reaker interlock h an apartment lock and can be unlocked for operation with either key -1 or -1. reaker F interlock h an apartment lock and can be unlocked for operation with either key -1 or -1. reaker G interlock h an apartment lock and can be unlocked for operation with either key -1 or -1. ll rear access doors are locked closed. ll keys for rear access doors (K-1 through K-9) are held in transfer interlocks. P R o open rear access doors K-7, K-8 and K-9 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Open breaker. 4. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 5. Insert key -1 and -1 in transfer interlock. 6. urn key -1 in transfer interlock. Keys K-7, K-8, and K- 9 are now free. Keys -1 and -1 are now held. 7. Insert keys K-7, K-8, and K-9 in their respective rear access door interlocks and turn to unlock. Keys K-7, K-8, and K-9 are now held. 8. Open the rear access doors ote: his symbol represents an interlock with an apartment lock. n apartment lock is a single cylinder that will accept two different keys - but only one key at a time.

16 Scheme 18 o prevent paralleling of lines,, and. hree loads, fed from any source (three tie-breakers). Scheme 19 o prevent paralleling lines,,, and. Four loads fed from any source (four tie-breakers) F G M reaker is closed to supply load M. reaker is closed to supply load. reaker is closed to supply load P. Keys -1, -1, and -1 are held in L-O interlocks on breakers, and. ie-breakers,, and F are locked open. Mter or apartment lock interlocks are mounted on tiebreakers,, and F, and can be unlocked for operation with either keys -1 or -1, -1 or -1, and -1 or -1, respectively. F o transfer load M from breaker to breaker : 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key - 1 is now free. 3. Insert key -1 in L-O interlock on tie-breaker and turn to unlock. Key -1 is now held. 4. lose tie-breaker. Reverse sequence to restore service through breaker. o transfer load M and from breakers and to breaker : 1. lose tie-breaker above. 2. Open breaker. 3. urn key -1 in L-O interlock on breaker to lock open. Key - 1 is now free. 4. Insert key -1 in L-O interlock on tie-breaker and turn to unlock. Key -1 is now held. 5. lose tie-breaker. Reverse sequence to restore service (loads M and ) through breakers and. o transfer load P from breaker to breaker : 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L-O interlock on tie breaker F and turn to unlock. Key -1 is now held. 4. lose tie-breaker F. Reverse sequence to restore service through breaker. F P M -1-1 reaker is closed to supply load M. reaker is closed to supply load. reaker is closed to supply load P. reaker is closed to supply load R Keys -1, -1, -1, and -1 are held in L-O interlocks of breakers,,, and. ie breakers, F, G, and H are locked open. reaker interlock h a mter or apartment lock and can be unlocked with either key -1 or -1. reaker F interlock h a mter or apartment lock and can be unlocked with either key -1 or -1. reaker G interlock h a mter or apartment lock and can be unlocked with either key -1 or -1. reaker H interlock h a mter or apartment lock and can be unlocked with either key -1 or -1. o transfer load M from breaker to breaker : 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L-O interlock on tie-breaker and turn to unlock. Key -1 is now held. 4. lose tie-breaker. Reverse sequence to restore service through breaker. o transfer load M and from breaker and to breaker : 1. lose tie-breaker above. 2. Open breaker. 3. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 4. Insert key -1 in L-O interlock on tie-breaker F and turn to unlock. Key -1 is now held. 5. lose tie-breaker F. Reverse sequence to restore service (M and ) through breakers and. o transfer load R from breaker to breaker : 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L-O interlock on tie-breaker G and turn to unlock. Key -1 is now held. 4. lose tie-breaker G. Reverse sequence to restore service through breaker. o transfer load M from breaker to breaker : 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L-O interlock on tie-breaker H and turn to unlock. Key -1 is now held. 4. lose tie-breaker H. Reverse sequence to restore service through breaker. H P H -1-1 G F R -1-1 ote: his symbol represents an interlock with an apartment lock. n apartment lock is a single cylinder that will accept two different keys - but only one key at a time. ny of the loads M,, P, or R can be transferred from its own supply to any adjacent supply ote: his symbol represents an interlock with an apartment lock. n apartment lock is a single cylinder that will accept two different keys - but only one key at a time.

17 Scheme 20 o prevent paralleling three power sources through a common tie bus not normally in service. o permit feeding any load bus from a second power source through the tie bus. o permit one power source to supply all three load busses through the tie bus. Line 1 Line 2 Line 3 reakers,, and are normally closed. reakers,, and F are normally open. Under normal conditions keys -1 and -5 are held in breaker interlock, keys -2 and -5 are held in breaker interlock, and keys -3 and -5 are held in breaker interlock. o transfer load from line o. 1 to line o. 2 or line o. 3 through the tie bus, proceed follows: Load us 5 1 Load us Load us ie us F Open breaker. 2. urn key -1 in L-O interlock on breaker to lock breaker open. Keys -1 and -5 are now free. 3. Insert key -1 in L-O interlock on breaker and turn to unlock. Key -1 is now held. 4. lose breaker. 5. Insert key -5 in L-O interlock on either breaker or F and turn to unlock. Key -5 is now held. 6. lose breaker or F (whichever is selected). Reverse sequence to restore load to line o. 1. o transfer load from lines o. 1 and o. 2 to line o. 3 through tie bus, proceed follows: 1. lose breaker per steps 1 to 4 above. 2. Open breaker. 3. urn key -2 in L-O interlock on breaker to lock breaker open. Keys -2 and -5 are now free. 4. Insert key -2 in L-O interlock on breaker and turn to unlock. Key -2 is now held. 5. lose breaker. 6. Insert one of the -5 keys from either breaker or in L-O interlock on breaker F and turn to unlock. Key -5 is now held. 7. lose breaker F. Reverse sequence to restore load to lines o. 1 and o ote: his symbol represents an interlock with an apartment lock. n apartment lock is a single cylinder that will accept two different keys - but only one key at a time. Scheme 21 o prevent paralleling three power sources through a common tie bus not normally in service. o permit feeding any load bus from a second power source through the tie bus only when authorized by supervisor. o permit one power source to supply all three load busses through the tie bus only when authorized by supervisor. Line 1 Line 2 Line Load us Load us Load us reakers,, and are normally closed. reakers,, and F are normally open. Under normal conditions key -1 is held in breaker interlock, key -2 is held in breaker interlock, and key -3 is held in breaker interlock. Key -5 is retained by supervisor. o transfer load from line o. 1 to line o. 2 or line o. 3 through tie bus, proceed follows: 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock breaker open. Key -1 is now free. 3. Insert key -1 in L-O interlock on breaker and turn to unlock. Key -1 is now held. 4. lose breaker. 5. Insert supervisor's key -5 (only one -5 is available) in L-O interlock on either breaker or F and turn to unlock. Key -5 is now held. 6. lose breaker or F (whichever is selected). Reverse sequence to restore load to line o ie us F 5 SUPRVISORY KY o transfer load from lines o. 1 and o. 2 to line o. 3 through tie bus, proceed follows: 1. lose breaker per steps 1 to 4 above. 2. Open breaker. 3. urn key -2 in L-O interlock on breaker to lock breaker open. Key -2 is now free. 4. Insert key -2 in L-O interlock on breaker and turn to unlock. Key -2 is now held. 5. lose breaker. 6. Insert supervisor's key -5 in L-O interlock on breaker F and turn to unlock. Key -5 is now held. 7. lose breaker F. Reverse sequence to restore load to lines o. 1 and o ote: his symbol represents an interlock with an apartment lock. n apartment lock is a single cylinder that will accept two different keys - but only one key at a time.

18 Scheme 22 o prevent paralleling incoming primary sources, lines 1 and 2, through primary tie bus disconnect. o prevent operation (open or closed) of the disconnects under load. Permits one power source to supply both loads through tie bus. Scheme 23 (ontinued) Line 1 Line 2 Line 1 Line Load 1 Load 2 Load 1 Load 2 Under normal conditions breakers and are closed, disconnects and are locked closed, and tie bus disconnect is locked open. Keys -1 are held in L-O interlock on breaker and L- interlock on tie bus disconnect. Keys -2 are held in L-O interlock on disconnects and. Keys -3 are held in L-O interlock on breaker and L- interlock on tie bus disconnect. Keys -4 (free keys) are shown removably held in the L- interlocks on disconnects and. o transfer load o. 1 from line 1 to line 2 through bus tie disconnect, proceed follows: 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L- interlock on disconnect and turn to unlock. Keys -1 and -4 are now held. 4. Open disconnect. 5. urn key -2 in L-O interlock on disconnect to lock open. Key - 2 is now free. 6. Insert keys -2 and free key -4 (from L- interlock on disconnect ) in L-O interlock on bus tie disconnect and turn to unlock. Keys -2 and -4 are now held. 7. lose tie bus disconnect. 8. urn key -3 in L- interlock on disconnect to lock closed. Keys -1 and -3 are now free. 9. Insert key -1 in L-O interlock on breaker and turn to unlock. Key -1 is now held. 10. lose breaker. Reverse sequence to restore load o. 1 to line 1. o transfer load o. 2 from line 2 to line 1 through bus tie disconnect, proceed in a similar manner. Scheme 23 o prevent paralleling incoming primary sources, lines 1 and 2, through the primary tie bus disconnect or the secondary tie bus breaker. o prevent operation (open or closed) of the disconnects under load. Permits one power source to supply both loads through either the primary or secondary tie bus. Under normal conditions breakers and are closed, breaker is locked open, disconnects and are locked closed, and tie disconnect is locked open. Keys -1 are held in L-O interlock on breaker and L- interlock on primary tie bus disconnect. Keys -2 are held in L-O interlocks on disconnects and. Keys -3 are held in L-O interlock on breaker and L- interlock on primary tie bus disconnect. Keys -4 (free keys) are shown removably held in the L- interlocks on disconnects and. Keys -5 are held in L-O interlocks on breakers and. o transfer load o. 1 from line 1 to line 2 through primary bus tie disconnect, proceed follows: 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Keys -1 and -5 are now free. 3. Insert key -1 and free key -4 in L- interlock on disconnect and turn to unlock. Keys -1 and -4 are now held. 4. Open disconnect. 5. urn key -2 in L-O interlock on disconnect to lock open. Key - 2 is now free. 6. Insert key -2 and free key -4 (from L- interlock on disconnect ) in L-O interlock on primary bus tie disconnect and turn to unlock. Keys -2 and -4 are now held. 7. lose bus tie disconnect. 8. urn key -3 in L- interlock on bus tie disconnect to lock closed. Keys -1 and -3 are now removable. 9. Insert key -1 in L-O interlock on breaker and turn to unlock. Key -1 is now held. 10. lose breaker. Reverse procedure to restore service to line 1. Load o. 2 can be supplied from o. 1 through the primary bus tie in a similar manner. o transfer load o. 1 from line 1 to line 2 through the secondary tie breaker, proceed follows: 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Keys -1 and -5 are now removable. 3. Insert key -5 in L-O interlock on tie breaker and turn to unlock. Key -5 is now held. 4. lose tie breaker. Reverse procedure to restore service on line 1. Load o. 2 can be supplied from line o. 1 through the secondary tie breaker in a similar manner.

19 Scheme 24 o prevent paralleling incoming primary sources, lines 1 and 2. o prevent operation (open or closed) of the disconnects under load. (Permits transformer primary disconnects K & L to open and close the transformer magnetizing current.*) Permits isolating breakers for servicing. Permits one power source to supply both loads through tie bus. Line 1 Line F 1 G H -1 1 o transfer load o. 1 from line 1 to line 2 through bus tie disconnect, proceed follows: 1. Open breaker. 2. urn key -2 in L-O interlock on breaker to lock open. Key -2 is now free. 3. Open breaker. 4. urn key -4 in L-O interlock breaker to lock open. Keys -1 and -4 are now free. 5. Insert key -2 from L-O interlock on breaker and key -1 from L-O interlock on breaker in L- interlock on disconnect F and turn to unlock. Keys -1 and -2 are now held. 6. Open disconnect F. 7. urn key -3 in L-O interlock on disconnect F to lock open. Keys -3 and -1 are now free. 8. Insert key -1 in L-O interlock on bus tie disconnect and turn to unlock. Key -1 is now held. 9. lose bus tie disconnect. 10. urn key -1 in L- interlock on bus tie disconnect to lock closed. Keys -1 and -1 are now free. 11. Insert key -1 in L-O interlock on breaker and turn to unlock. Keys -1 and -4 are now held. 12. lose breaker. Reverse sequence to restore load o. 1 to line 1. o transfer load o. 2 from line 2 to line 1, proceed in a similar manner o isolate breaker for servicing, proceed follows: K L -4-4 L-O- L-O Proceed from normal position with operations in 1 through 7 above. 2. Insert key -3 in L- interlock on disconnect and turn to unlock. Key -3 is now held. 3. Open disconnect. 4. urn key -2 in L-O interlock on disconnect to lock open. Key -2 is now free. 5. Return key -2 to breaker and unlock for operation during servicing. o isolate breaker for servicing, proceed in a similar manner. o isolate breaker for servicing, proceed follows: 4 4 Load 1 Load 2 Under normal conditions breakers,,, and are closed, disconnects, F, G, H, K, and L are locked closed, and bus tie disconnect is locked open. Keys -1 are held in L-O interlock on breaker and L- interlock on bus tie disconnect. Keys -2 are held in L-O interlocks on breaker and disconnect. Key -3 is held in L-O interlock on disconnect F. Key -4 is held in L-O interlock on breaker. Keys -1 are held in L-O interlock on breaker and L- interlock on bus tie disconnect. Keys -2 are held in L-O interlocks on breaker and disconnect G. Key -3 is held in L-O interlock on disconnect H. Key -4 is held in L-O interlock on breaker. Keys -1 are held in L-O interlock on disconnects F and H. 1. Open breaker. 2. urn key -4 in L-O interlock on breaker to lock breaker open. Keys -1 and -4 are now free. 3. Insert key -4 in L-O- interlock on disconnect K and turn to unlock. Key -4 is now held. 4. Open disconnect K. 5. urn key -4 in L-O- interlock on disconnect K to lock open. Key -4 is now free. 6. Return key -4 to breaker and unlock for operation during servicing. o isolate breaker for servicing, proceed in a similar manner. * o prevent primary disconnects K and L from opening magnetizing current only, additional interlocks should be provided for disconnect K and L.

20 Scheme 25 o prevent opening fuse compartment door when the interrupter switch is closed. o prevent closing interrupter switch until fuse compartment door is locked closed. Scheme 27 o prevent operation (open or closed) of interrupter switch when breaker is closed. o prevent opening fuse compartment door when the interrupter switch is closed. o prevent closing interrupter switch until fuse compartment door is locked closed. Permits the breaker to be serviced and operated while the interrupter is locked open Fuse compartment door and interrupter are shown in closed position. Key -1 is held in interrupter interlock. L-O- 1. Open interrupter. 2. urn key -1 in L-O interlock on interrupter switch to lock open. Key -1 is now free. 3. Insert key -1 in L- interlock on fuse compartment door and turn to unlock. Key -1 is now held. 4. Open fuse compartment door. Scheme 26 o prevent operation (open or closed) of interrupter switch when breaker is closed. Permits the breaker to be serviced and operated while the interrupter switch is locked open L-O- reaker, fuse compartment door and interrupter are shown in closed position. Key -1 is held in breaker interlock and key -2 is held in interrupter interlock. o service breaker, proceed follows: 1 Interrupter and breaker are shown in closed position. Key -1 is held in breaker interlock. 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L-O- interlock on interrupter and turn to unlock. Key -1 is now held. 4. Open interrupter. 5. urn key -1 in L-O- interlock on interrupter to lock open. Key -1 is now free. 6. Return key -1 to breaker interlock and unlock for operation of breaker during servicing. -1 L-O- 1. Open breaker. 2. urn key -1 in L-O interlock on breaker to lock open. Key -1 is now free. 3. Insert key -1 in L-O- interlock on interrupter and turn to unlock. Key -1 is now held. 4. Open interrupter. 5. urn key -1 in L-O- interlock on interrupter to lock open. Key -1 is now free. 6. Return key -1 to breaker interlock and unlock for operation of breaker during servicing. o open fuse compartment door, proceed follows: 1. Proceed from normal position with operations in 1 through 4 above. 2. urn key -2 in L-O interlock on interrupter switch to lock open. Key -2 is now free. 3. Insert key -2 in L- interlock on fuse compartment door and turn to unlock. Key -2 is now held. 4. Open fuse compartment door.