Figure 31 Working spaces behing electrical equipment 38 Figure 32 Distribution panelboard 41 Figure 33A Correct wiring of duplex receptacles 42 Figure

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1 Figure 1 An example of a utility substation covered under Figure 2 Symbols of common Nationally Recognized Testing Laboratories (NRTLs) 8 Figure 3 Example of the interrupting rating marked on an overcurrent device 11 Figure 4 NEMA Enclosure Specifications for Indoor Nonhazardous Locations 12 Figure 5 NEMA Enclosure Specifications for Outdoor Nonhazardous Locations 13 Figure 6 Example of equipment affected by deteriorating agents 14 Figure 7 ANSI/NECA , Standard Practice for Good Workmanship in Electrical Contracting 15 Figure 8 Example of one type of knockout plug 15 Figure 9 Unused opening in a disconnect switch 15 Figure 10 Example of corrosive chemical residue 16 Figure 11 Note the damaged handle on this disconnect switch 16 Figure 12 Example of electrical equipment not firmly secured 17 Figure 13 Example of electrical equipment not firmly secured 17 Figure 14 Even with ventilation openings clear, equipment may not be able to dissipate heat properly 18 Figure 15 Example of lack of maintenance leading to inadequate ventilation of electrical equipment 18 Figure 16 None of these connections are identified for multiple wire termination 19 Figure 17 Sample mechanical splicing devices 20 Figure 18 Conductors mechanically joined and soldered 21 Figure 19 Insulating a splice with electrical tape 22 Figure 20 Generator nameplate 22 Figure 21 Each disconnect and circuit requires identification 23 Figure 22 Actual picture of disconnect switches 24 Figure 23 Disconnect switch located on machine 24 Figure 24 Requirements for entrance and egress from working space 27 Figure 25 Condition (A)-Live parts on one side and no live or grounded parts on the other side 28 Figure 26 Condition (B)-Exposed live parts on one side and grounded parts on the other side 29 Figure 27 Condition (C)-Exposed live unguarded parts on both sides 31 Figure 28 Example of warning sign for unqualified persons 33 Figure 29 An outdoor substation preventing entrance by a locked fence 34 Figure 30 Requirements for entrance and egress from workspace 36

2 Figure 31 Working spaces behing electrical equipment 38 Figure 32 Distribution panelboard 41 Figure 33A Correct wiring of duplex receptacles 42 Figure 33B Incorrect wiring of duplex receptacles 43 Figure 33C Incorrect wiring of duplex receptacles 44 Figure 33D Incorrect wiring of duplex receptacles 44 Figure 34 Duplex receptacle correctly wired for designated terminals 45 Figure 35A Example of portable GFCI device 47 Figure 35B HD-Pro 480V portable GFCI by TRC 47 Figure 36 Open conductors installed on insulators on the surface of a building 50 Figure 37 Minimum climbing spaces for power conductors located over communication conductors 51 Figure 38 Required clearance between a roof and outside branch circuits, feeders, and service 53 Figure 39 Minimum distance of 3 feet from sloping roof to overhead wires 53 Figure 40A Minimum clearance from roof to wires over slope roof overhang 54 Figure 40B Minimum clearance from roof to wires over flat roof overhang 55 Figure 41 Three acceptable arrangements for service-entrance disconnecting means 56 Figure 42 Common types of fuses: socket type (top) and cartridge 58 Figure 43 Cutaway view of a circuit breaker 59 Figure 44 Disconnects for overcurrent devices 60 Figure 45 SWD & HID markings on typical circuit breaker 61 Figure 46-1A No current flows unless there is a complete loop 63 Figure 46-1B If the loop (circuit) is not complete no electrons can return 63 Figure 46-1C Friction (resistance) inside of a conductor produces heat 63 Figure 46-1D A well-designed system has minimum resistance 63 Figure 46-2A When current flows through a conductor, a magnetic field is forced outside of the conductor 64 Figure 46-2B In a conventional circuit, the current flowing in the returning line produces a field 64 Figure 46-2C If the outgoing and returning conductors of a circuit (loop) are close together, the two magnetic fields cancel each other 64 Figure 46-3 Grounding (bonding) conductors must be carried with the supply conductors 65 Figure 46-4 Ground impedance must be low 67 Figure 46-5A The equipment grounding conductor protects against hazards of voltage between enclosures 69 Figure 46-5B The grounding-electrode conductor protects against hazards of voltage between enclosures and their surroundings 69

3 Figure 46-6A A grounded system has an intentional connection from a current-carrying conductor to the equipment grounding conductor and to the grounding electrode 69 Figure 46-6B An ungrounded system has no main bonding jumper, but the equipment grounding conductors are required exactly as in the grounded system 69 Figure 46-7A In a grounded system each fault clears immediately, over a predictable path to the source 69 Figure 46-7B In an ungrounded system fault current flows between faults over unpredictable paths 69 Figure 46-8 System and equipment grounding 70 Figure volt, three-wire DC system. The neutral conductor is grounded at the source 71 Figure 48 Grounded 2-wire DC system supplying an electroplating operation 72 Figure 49 AC circuits under 50 volts requiring grounding 73 Figure 50 Typical connections for a GROUNDED 3-phase, 4-wire, service supplied system 78 Figure 51 Typical connections for a UNGROUNDED 3-phase, 3-wire, service supplied system 79 Figure 52 Simplified diagram of a GROUNDED system 80 Figure 53 Simplified diagram of an UNGROUNDED system 80 Figure 54 Cord- and plug-connected equipment without a grounding conductor 83 Figure 55 Cord- and plug-connected equipment with a grounding conductor 84 Figure 56 Grounding methods for fixed equipment using a separate conductor or metal enclosures as the equipment grounding conductor 86 Figure 57 Grounding method for fixed equipment using circuit conductor enclosures as equipment grounding conductor 86 Figure 58 Motor suitably grounded by its attachment to grounded structure 87 Figure 59 Equipment considered effectively grounded 88 Figure 60 Derived neutral for an ungrounded delta-connected system showing the neutral grounded through an impedance 89 Figure 61 Non-current-carrying metal parts connected 89 Figure 62 Ground fault detection and relaying 90 Figure 63 Typical ground-fault indicator lights integrated into electrical equipment to indicate a ground-fault on a 3-phase delta system 91 Figure 64 Isolated grounding electrode 92 Figure 65 Temporary wiring arrangement permissible for duration of construction, remodeling, maintenance, repair, or demolition of structures 94 Figure 66 Temporary feeders run as open conductors 96 Figure 67 Temporary branch circuit run as open wiring on insulators 97 Figure 68 Receptacle used for temporary wiring protected by a GFCI circuit breaker 98 Figure 69 Earth returns 99

4 Figure 70 Plug connector for use with temporary circuits 100 Figure 71 Overloaded multiple ladder-type cable trays 102 Figure 72A Unused openings 104 Figure 72B Various standard trade sizes of knockout covers 104 Figure 73 Knife switches (A and B) 105 Figure 74 Double-throw knife switches with locking device 106 Figure 75 Typical multiconductor insulation 108 Figure 76 Wet-location portable hand lamp with step-down transformer 111 Figure 77 Non-dead-front attachment plug 112 Figure 78 Receptacles and plugs with NEMA configurations 113 Figure 79 Single outlet weatherproof cover suitable for use in wet locations 114 Figure 80 Electric space heater with exposed heating elements guarded by a protective grill 115 Figure 81 Example of a Motor Control Center (MCC) 116 Figure 82 Motor disconnecting means 117 Figure 83 Labeling required when disconnects are out of sight 118 Figure 84 Locking controller disconnecting means 118 Figure 85 Manually operable switch within sight 119 Figure 86 Motor protection methods 120 Figure 87 Unguarded commutators, collectors, and brushes housed within motor 121 Figure 88 Typical Class 2 circuit 122 Figure 89 Transformer for power-limited, fire-protective signaling circuit 123 Figure 90 Examples of safeguarding methods for transformers 124 Figure 91 Location of disconnect for gantry crane 127 Figure 92 Second disconnect not required 128 Figure 93 Interconnected control panels 129 Figure 94 Location of disconnect in data processing center 132 Figure 95 Typical operation of disconnecting means 132 Figure 96 Interlocks 133 Figure 97 Induction heat-treating process 135 Figure 98 The boundaries of the cell line as a single functional unit 137 Figure 99 Isolating transformer supplying hand-held double-insulated tool for use in cell line working zone 139 Figure 100 NEMA configurations for 2-pole 3-wire grounding plugs and receptacles 141 Figure 101 Distance of receptacles to permanently installed swimming pool 142 Figure 102A Ground-fault circuit interrupter 143 Figure 102B Receptacle-type ground-fault circuit interrupter (GFCI) 144 Figure 103 GFCI requirement for fountains applies to ornamental fountains of this type 145 Figure 104 Explosion occurring in general-purpose equipment 153 Figure 105 A fluorescent hazardous-duty hand lamp for Classified Locations 155

5 Figure 106 Design features of a totally enclosed, fan-cooled, explosion-proof motor 156 Figure 107 Explosion occurring in approved equipment 157 Figure 108 Internal explosive pressure 158 Figure 109 Threaded joint design 159 Figure 110 Openings designed into ground joint 159 Figure 111 Class 1, Division 1 hazardous location 163 Figure 112 Construction of Type MI (mineral insulated) cable 164 Figure 113 Sealing 165 Figure 114 Bonding in Class 1 hazardous (classified) locations 165 Figure 115 Class I, Division 2 hazardous locations 168 Figure 116 Class II hazardous locations 169 Figure 117 Preventing dust from entering the dust-ignition-proof enclosure by sealing between enclosures 172 Figure 118 Preventing dust from entering the dust-ignition-proof enclosures by horizontal distance 173 Figure 119 Preventing dust from entering the dust-ignition-proof enclosure by vertical distance 173 Figure 120 Totally enclosed pipe-ventilated motor 174 Figure 121 Bonding in Class II hazardous (classified) locations 174 Figure 122 Class III hazardous locations 176 Figure 123 Improperly supported cable and properly supported cable 180 Figure 124 Isolating switches 182 Figure 125 Normal and emergency lighting circuits where permitted in a common junction box 183 Figure 126 Example of a Class 1 power-limited circuit 185 Figure 127 Example of a Class 1 remote control circuit 185 Figure 128 Thermostat control circuit, Class Figure 129 Well-laid-out fire control panel has barriers to minimize wiring errors 189 Figure 130 Identification of fire protective signaling circuits 190 Figure 131 Protection of communication system from accidental contact with power conductors 191 Figure 132A Group lockout/tagout of electrical disconnecting means 204 Figure 132B Cable lockout device for several electrical disconnects 204 Figure 132C Lockout procedures affixed to a pump motor 205 Figure 133 Example of danger tape used to establish work zone to restrict approach by unqualified persons 209 Figure 134 Metallic crane booms may come in contact with overhead lines 212 Figure 135 Example of Rubber Insulating Glove Label 218