2012 Electrical Code Changes Module 2 Sections 6-16

Transcription

1 2012 Electrical Code Changes Module 2 Sections 6-16 ETEL-11(02)-00 ( )

2 Table of Contents Section 6 Services and Service Equipment... 2 Section 8 Circuit Loading and Demand Factors... 6 Section 10 Grounding and Bonding... 8 Section 12 Wiring Methods Section 14 Protection and Control Section 16 Class 1 and Class 2 Circuits British Columbia Safety Authority,

3 2012 ELECTRICAL CODE CHANGES Module 2 There have been numerous changes to the 2012 Canadian Electrical Code. The following material only describes changes which may be considered as major. For complete Code information, refer to the 2012 Canadian Electrical Code available at Please note: minor electrical code changes are not covered in this material. Section 6 Services and Service Equipment Rule Number of supply services permitted (see Appendices B and I) Subrule (1) has been revised to clarify that two or more services of the same voltage may not be supplied to a building. Previous wording included a reference to from the same system of any one supply authority, which may have left the User unsure of the intent. An exception is provided in revised item 1(a) where additional services may be provided to fire pumps in accordance with (1). Rule Consumer s service equipment location (see Appendices B and G) Subrule (1) - No change has been made to items (a) and (b), the equipment must still be located to comply with Hydro requirements and must be readily accessible (a defined term). This second item is important in relation to new subrule (3). Item (c) has been revised, first by recognizing a new Subrule (3) has been added to the Rule and secondly by listing the undesirable locations where service equipment shall not be installed. New Subrule (3) permits the consumer s service box to be installed on the outside of the building OR on a pole provided it is installed in an enclosure approved for the location and is protected from mechanical damage where located less than 2m above ground. Where the service box is located outside, a main overcurrent device shall be installed in the dwelling unit unless the permit holder provides documentation confirming the outside main O/C device will properly protect the interior conductors. Acceptable documentation will include confirmation of the operating characteristics of the O/C device in low ambient temperatures that may be expected in the region. A service box installed outdoors shall be readily accessible in accordance with Rule (1) (b) and the definition obtained in Section 0 of the BC Electrical Code. British Columbia Safety Authority,

4 The new Subrule will permit the installation of an exterior service box. This will allow the use of any wiring method approved for use as a feeder for the location involved (i.e. Type NMSC to a suite panel as shown). The new Subrule will permit the installation of an exterior service box outside. This will allow the use of any wiring method approved for use as a feeder (i.e. Type NMSC) for the location involved. This diagram above shows a duplex meter base in use. British Columbia Safety Authority,

5 British Columbia Safety Authority,

6 Rule Installation of underground consumer s service conductors The wording in Subrule (1) has been revised to clarify that selection of an approved wiring method must also include ensuring it is suitable for the intended location and application. New Subrule (1)(b)(ii)B permits a single or multi-conductor cable to be spliced where a transition is made to comply with Rule Rule requires the ampacity of conductors to be based on the temperature rating marked on equipment such as circuit breakers, panel boards and similar equipment. Where no marking appears on equipment (at both ends), the ampacity listed for 90 C rated conductors may be used. METERBASE NOT MARKED FOR TEMPERATURE LIMITATION OF CONDUCTORS PANEL AND BREAKERS O APPROVED FOR 60/75 C TEMPERATURE RATINGS WIRE SIZE O SIZED TO 75 C WIRE SIZED TO O 90 C Nema 3R Junction Box Rule (1)(b)(ii) refers to service cables. The splicing of service conductors for this purpose is restricted to service cable installations only. Rule Installation of overhead consumer s service conductors The wording of Subrule (1) has been revised to clarify that where consumer s service conductors are installed at any point above ground on a building or structure, use of a wiring method that complies with the list in this Rule is required. Previous Code wording was imprecise and seemed to refer to consumer s service conductors connected to an overhead service connection located above ground. By definition, an overhead service is above ground. British Columbia Safety Authority,

7 Rule Use of joints in consumer's service neutral conductors New Subrule (c) has been added to permit a splice in the service neutral where a transition is made to comply with the temperature termination rating of a device or equipment as per Rule This subrule applies to service cable only. Rule requires the ampacity of conductors to be based on the temperature rating marked on equipment such as circuit breakers, panel boards and similar equipment. This may result in requiring a larger sized conductor to be used for any given ampacity. Where no termination marking appears on equipment, the ampacity listed for 90 C rated conductors may be used. Section 8 Circuit Loading and Demand Factors Rule Single dwellings (see Appendix B) A new revision in Subrule (1) requires the demand load for electric vehicle charging equipment be added to a load calculation at 100%. Note that Rule (o) sets the requirement as to when an EV receptacle must be installed, basically when building code dictates a requirement (not required in present edition of the BC Building Code and Local Bylaws). British Columbia Safety Authority,

8 Rule Apartment and similar buildings (see Appendix B) A new item (d) has been added to 8-202(3). This requires any electric vehicle charging loads not located in dwelling units to be added to the main service ampacity calculation at a demand factor of 100%. Sample Main Service Calculation A fifty five suite apartment has V/20A Type 5-20R GFCI receptacles installed for Electrical Vehicle charging in the outdoor parking lot. Each EV receptacle is supplied by a dedicated circuit rated not less than 20 A as required by Rule When the connected load for each branch circuit is undetermined, the calculated load may be taken at 80% of the rating of the circuit. 120 V x 20 A x 80% = 1920 W Therefore 27 receptacles x 1920 W = 51,840 W The total calculated EV load shall be added to the other calculated loads when determining the minimum ampacity of service conductors supplying a main service. For the example below, the main service equipment is marked for continuous operation at 80% of the ampere rating of its O/C device. This results in the EV charging load and house load being multiplied by 125%. EV load is added at 100% of the calculated load (demand) x 125%. Note: the house load would have been first taken at 75% as required in new Subrule (e) but it is not shown in the example. Rule (3)(a) (suite loads) = 80,000 W Rule (3)(b) (heat load) = 60,000 W Rule (3)(c) (A/C load) = 50,000 W Rule (3)(d) (EV loads) = 51,840 W x 125% Rule (3)(e) (house load) = 20,000 W x 125% British Columbia Safety Authority,

9 Section 10 Grounding and Bonding Rule Scope (see Appendix B) The scope of this section has been completely rewritten to clarify to the User the intention of this section. Appendix B provides further insight into the terms grounding and bonding. Rule Object The Object of this section has been completely rewritten to provide some rationale behind how grounding and bonding will improve safety in an electrical installation. Rule Grounding connections for equipment in an ungrounded system (see Appendix B) This new rule recognizes established engineering practices and has been added as a requirement to ensure uniformity around ungrounded system designs. Subrule (1) - Some system designs call for installation of neutral grounding devices used for the purpose of controlling the ground fault current or the voltage-to-ground of an alternating-current system. Subrule (1) has been added to ensure the system ground connection is not connected directly to the neutral which would defeat the purpose of the system design. Subrule (2) This Rule stipulates the grounding conductor connection shall be made to the specified terminal in the service box or equivalent. Appendix B notes provide further information on the location of system grounding connections in ungrounded systems to ensure an essentially safe installation and proper operation of protection devices. British Columbia Safety Authority,

10 In the above example from Appendix B, the neutral is not solidly grounded. The bonding screw is removed in the service box, which isolates the neutral conductor from the system ground and bonding path. The neutral is connected in series with the grounding conductor through a neutral grounding resistor. This design is used for the purpose of controlling the ground fault current or the voltage-to-ground of an alternating-current system. Rule Bonding equipment to grounded system conductor (see Appendix B) Subrule (1) requires the service box to be bonded to the service box enclosure which completes the connection between the grounding and bonding systems. Equipment marked as suitable for service equipment is supplied with a factory supplied bonding screw or jumper. Subrule (2) recognizes the practice of using a field installed bonding jumper sized to Table 16 when equipment is not provided with a factory installed bonding screw or strap such as a load centre installed in a garage or other outbuilding supplied from the same service. Subrule (3) requires the system neutral (grounded conductor) to be connected to the bonding terminal in an enclosure by the use of a lug or equivalent device, just as the connection would be made if the enclosure was metallic. British Columbia Safety Authority,

11 The Appendix B Note to Subrule (4) clarifies an additional bonding conductor is not required when the wiring method is a non-metallic (RPVC) conduit and the grounded service conductor (neutral) is used to bond the meter base. Subrule (6) has similar wording to the previous Code and should be remembered by all as the requirement to remove the bonding screw in panel boards in the same building to isolate the neutral from the metallic parts. Rule Ground electrodes (see Appendix B) Rule (2)(a)(i) has been revised to require rod electrodes be bonded together with a conductor sized as per Rule British Columbia Safety Authority,

12 Rule Grounding conductor size for DC Systems New Subrule (2) has been added to require the grounding conductor for Photovoltaic and Renewable energy systems to be sized as required in Rule This harmonizes the grounding conductor size required (#6) for AC systems when a ground electrode conforming to Rule is selected Electrical Code and Earlier 2012 Electrical Code British Columbia Safety Authority,

13 Rule Grounding conductor size for alternating-current systems and for service equipment (see Appendix B) This applies to all low voltage system grounding conductors connected to grounding electrodes which comply with Rule , regardless of the size of ampacity of the low voltage service. Bonding conductor shall continue to be sized as required by other Section 10 Rules. The size of the system grounding conductor connected to a grounding conductor conforming to Rule shall not be smaller than #6 copper. Caution: The requirements for HV grounding are as specified in Section 36. British Columbia Safety Authority,

14 60/75 degree rating for break er term inations 60/75 degree rating for breaker term inations 60/75 degree rating for breaker term inations 60/75 degree rating for br eak er term inations 60/75 degree rating for breaker ter m ina tion s Rule Bonding conductor size (see Appendix B) Subrule (2) has been revised to clarify that a bonding conductor shall be paralleled and installed in each raceway or cable. The bonding conductor shall be sized in accordance with Table 16 and based upon the ampacity of the circuit conductors contained within the raceway or cable. 800A In parallel runs where bonding conductors are required (ie: pvc raceways)the bonding conductor must run in each raceway sized to conductor in that raceway British Columbia Safety Authority,

15 Section 12 Wiring Methods Rule Underground installations (see Appendix B) Subrule (4) has been revised. The screened sand permitted to be used to bed underground raceways shall be sized to 4.75mm maximum. Previous editions allowed for 6mm screened sand. This harmonizes with CSA standards for sand and gravel particulate sizing. Rule Insulated conductors This Rule has been revised to include all conductor types (the reference to thermoplastic conductors has been removed) regardless of the insulation used. The rule cautions users about damage to conductors during and after installation when flexing or vibration in low ambient temperatures could cause damage to the insulation. Rule Conductors in parallel (see Appendix B) Subrule (1) allows circuit conductors to be run in parallel sets (no change). What has changed is that each phase or neutral set (if required) can be a different material (copper or aluminum usually) than the other phase or neutral sets. British Columbia Safety Authority,

16 Subrule (1) requires each parallel set to be made up of conductors of the same material, terminated in the same manner, etc. ( same type of lug arrangement and location on the buss). Rule still requires the raceway or cable sheaths enclosing each parallel set to be made of the same material and have the same physical characteristics (size, diameter, thickness) and include an equal number of conductors from each phase and the neutral. Subrule (2) has been added to allow for a single splice per conductor when required to meet the equipment temperature rating of Rule Each splice must be made in the same manner. o RW 90 sized as per 90 Col Single splice per conductor of parallel set permitted only for the application of rule o RW 90 sized as per 75 Col To or from o 75 C rated equipment To or from o unrated or 90 C rated equipment Approved splice device -same type required for each conductor British Columbia Safety Authority,

17 Subrule (3) allows each phase, polarity or (neutral) set to have characteristics different than other phase, polarity or (neutral) parallel sets. The following example shows that each raceway contains 1 aluminum Phase A, 1 copper Phase B, 1 aluminum Phase C and 1 copper Neutral. Rule Supporting of conductors (See Appendix B) Rule and specifically Subrules (1), (2), and (3) have been around a long time to address the damaging strain which can be imposed on the terminals of equipment during conductor terminations. Subrules (2) and (3) specifically addressed issues with special requirements where the weight of conductors in vertical raceways due to gravity could cause equipment failures. New Subrule (4) addresses similar concerns. The standard construction of armoured cable types such as Teck90, AC90 or ACWU90 do not provide for the internal support of the cables. On vertical runs the internal conductor assembly is affected by gravity and this can cause the internal conductor assembly to slip or slide down through the interlocked armour or cable sheath. This condition can result in strain being placed on the termination points (lugs) of each conductor due to their unsupported weight. In addition to this hazard, conductors which have been sharply bent over the edge of cable connectors can be damaged through insulation displacement, a condition which can take many years to develop, but can eventually cause electrical faults and equipment failure. Teck90 cable and other types of armoured cables are available with construction that provides internal support of the conductors. British Columbia Safety Authority,

18 A large number of strain relief devices are available from the suppliers. The type shown above is installed on a standard armoured cable connector and consists of a socket and wedge. The socket is secured to the cable connector and the one-piece wedge is installed around the conductors and into the socket. As gravity pulls on the wedge, it grips tighter on each conductor to hold it securely. British Columbia Safety Authority,

19 (4) Vertical runs of armoured or sheathed cable such as TECK90, RA90, RC90, AC90, and ACWU90 shall have the internal cable assembly supported at intervals not exceeding those specified in Table 21, or by (a) incorporating a bend or bends equivalent to a total of not less than 90 at intervals not exceeding the distances specified in Table 21; British Columbia Safety Authority,

20 (b) installation of a horizontal run of the cable not less than the length of the vertical run; or This method uses the cables own weight to reduce the strain which can be imposed on the terminations and the internal conductors. Caution should be taken to ensure the stress provided by an armoured cables weight is not transposed onto the equipment where it terminates. (c) use of cable that is specifically designed for vertical runs. Example of this cable include: Risertek 90 Cable (National Cable Specialists) CSA TECK90 (specialty construction) 3 Conductor Unshielded Armored Power Cable (5kV) (Allied Wire & Cable) These specialty cables are designed and manufactured with internal support built in. The construction of the internal jacket includes raised ridges. When the spiral armour is applied, it is embedded into the ridges to provide the required support. British Columbia Safety Authority,

21 Rule Running of cable between boxes and fittings (See Appendices B and G) Subrule (3) continues to allow Type NMSC cable to be fished except where metal sheeting or cladding, metal joists, metal top or bottom plates or metal studs are used in the construction of the building. The revision requires NMSC cable to be supported in accordance with Subrule (1) when typical steel stud construction is used. Subrule (4) requires that NMSC cables shall be secured within 300mm of any switch or receptacle wall opening (not the outlet) approved with an integral enclosure. In addition, a 300mm length of unbroken cable or 150mm cable end shall be left inside the wall at each device location so as to be available on the interior of the wall for future branch circuit work. British Columbia Safety Authority,

22 The above diagram is an example of where an installation uses devices with an integral box. The NMSC wiring is run and secured and the locations are marked. After the installation of the wall finish, the devices are installed using the integral box type. Rule Fished Cable Installation This rule still allows NMSC to be fished but has been revised to prohibit NMSC being fished where steel stud type construction is used. British Columbia Safety Authority,

23 Armoured Cable For many years the use of a short length of conduit has been accepted as a means of providing mechanical protection for armoured cables emerging from grade or for similar locations where mechanical protection is required. However acceptance of this practice generally depended on three things: 1) The conduit (usually PVC) was short and could be slid over the cable, or 2) The conduit was short enough that the armoured cable could be readily pushed through the conduit without much stress on the cable, and 3) The cable suffered no damage during or after installation Now the use of armoured cables drawn into raceways has been approved by CSA. To fully understand how an installation must be performed to comply with the Code, three Rules must be understood and consulted: 1) Rule Use of Armoured Cable, 2) Rule (1) - Radii of bends in armoured cables and 3) Rule Types of conductors and cables (in raceways) When armoured cable is installed, care must be taken not to damage the internal conductors or the armour (jacketed or otherwise). This includes ensuring the bending radius of any bends is of a size which will be large enough to not damage the armour, sheath or internal conductors during installation and using a pulling method, such as Kellems Grips, to attach the armour and internal conductors together to equalize the pulling strain. Rule Use (see Appendix B) Subrule (6) is a new revision that has been added to permit jacketed armoured cable to be installed in a raceway. Raceway is a defined term that includes conduit (rigid and flexible, metal and nonmetallic), electrical metallic and non-metallic tubing, underfloor raceways, cellular floors, surface raceways, wireways, cable trays, busways, and auxiliary gutters. Specific Rules regarding the bending of armoured cables during installation in raceways can be found in Rule British Columbia Safety Authority,

24 Rule Radii of bends in armoured cables Subrule (1) provides installation details for armoured cable installed in all applications except for installations in conduit or tubing. So the minimum bending radius applies to surface run, fished, pulled through structural framing, AND cabletray type of installations. It should be noted that some manufacturers have minimum bending radius specifications which are greater than listed here. Subrule (2) is a general rule which applies to all armoured cable installations. Subrule (3) applies to armoured cables installed in raceways consisting of conduit or tubing. Manufacturer s specifications (c) for installation shall take precedence over the bending radius requirements shown in items (a) and (b). The bending radii listed are the minimum acceptable and require detailed calculation. An option for not providing a detailed calculation, using a greater radius, is discussed later in Rule (2)(b)(ii). Rule Types of conductors and cables The Rule Title has been revised to include cables. Subrule (1) recognizes some cables are suitable for use in raceways. Table 19 should be consulted for these types of cables. New Subrules (2) (a) and (b) have been added to describe how armoured cable must be installed in a conduit or tubing to ensure compliance with the Code. Cable diameters may have to be determined using field measurements as provided for in Rule (c). Subrule (2) (a) specifies any armoured cable pulled into raceways must meet the conduit fill requirements of Table 8. British Columbia Safety Authority,

25 Subrule 2 (b)(i) - When an armoured cable is drawn into a conduit or tubing, significant force can be exerted on the external armour and internal conductors sufficient to damage either components. All manufacturer s of armoured cable produce specifications regarding the maximum pulling tension and sidewall bearing pressure. To ensure the pulling tension will not result in damage during installation, detailed calculations provided by a P.Eng or the cable manufacturer shall be provided to the AHJ to ensure compliance with these specifications. Note: there are no restrictions in this subrule on the length of the cable between pull points, the Code has only required that there be minimum bending radius provided in the conduit runs and compliance with manufacturer s specifications regarding pulling tension and sidewall bearing pressure as required by Rules (3) and (b)(1). Subrule (2)(b)(ii) - This Subrule provides alternative specifications for the installation of armoured cable in conduit or tubing which have been engineered for you in order to ensure no damage to the cable during installation. By using these specifications which include a limited number of 90 0 bends or their equivalent, large radius bends and a maximum length of conduit between draw-in points according to the cable type, detailed calculations provided by P. Eng s are NOT required but careful execution of the work is required. British Columbia Safety Authority,

26 Rule Conductors in Conduit (see Appendix B) Subrule (4) (d) has been revised to send the user to newly named Table 10A to obtain dimensions for conductor types commonly used in raceways. Rule Supports New Subrule (1) clarifies the requirements for supporting liquid-tight flexible conduit. The requirement to NOT use liquid tite flex conduit as a general purpose raceway is still there. New Subrule (2) permits liquid-tight flexible conduit to be fished. Rule Conductors in wireways Subrule (2) now recognizes each compartment of a divided wireway shall be treated separately when determining the maximum number of conductors (200) and the interior cross-sectional area permitted to be occupied by those conductors (20%). Existing Subrule (4) still permits the User to fill wireways to 40% where only signal and control conductors are installed. Rule Method of installation (see Appendix B) CSA C22.2 No and C22.2 No requires the marking on the cable tray to include the load/span rating of the cable tray. NEW SUBSECTION CABLEBUS Rule (Scope) through Rule (Ampacities of conductors in Cablebus) describe the Scope, Use of, Methods of installation, Connection to Other Wiring Methods, Provisions for Bonding and Ampacities of Conductors in Cablebus. Cablebus is designed, engineered, manufactured and certified as a system. The components are delivered to the installation site and are erected as per the manufacturer s specifications. Cablebus is generally used in large capacity systems where specified by designing engineers. Extensive Cablebus information and specifications is available on the MP Husky website at British Columbia Safety Authority,

27 Rule Outlet boxes (see Appendix B) New Subrule (3) has been added and existing Subrules (3) to (6) have been renumbered (4) to (7). Subrule (3) requires metallic fittings, when used to terminate non-metallic wiring methods to non-metallic boxes, to be bonded to ground. A bonding bushing is required. NON METALLIC BOX (IE: PVC ) FLEXIBLE CORD METALLIC FITTING TO BE BONDED TO GROUND WITH BONDING BUSHING Subrule (8) has been added to recognize switch and receptacle devices which come with an integral box as permitted in Rule (7). Subrule (9) has been added to require a ceiling outlet box, marked and approved for fan support, be used where the fan and its accessories weigh less than 16kg. Photo copyright C. Popejoy, 2011 British Columbia Safety Authority,

28 Rule Outlet box supports New Subrule (7) exempts those types of switch and receptacle devices having an integral box, for use with non-metallic-sheathed cable, from the requirements to provide adequate support. New Subrule (8) requires ceiling outlet boxes marked for fan support to be secured directly to the building structure or be attached by a bar hanger attached directly to the building structure. New Subrule (9) requires fan and their accessories weighing more than 16kg to be supported independently of the outlet box. Rule Entrance of conductors into boxes, cabinets, and fittings (see Appendix B) Subrule (3) has been revised to ensure tray cable, like NMSC, is terminated into a box connector. Subrule (7) has been revised. The prescribed measures to be taken to prevent the overheating of conductors and cables due to induced sheath currents have been moved to Rule Rule Wiring space in enclosures (see Appendix B) New Subrule (4) has been added to allow enclosures which house o/c devices, controllers or externally operated switches, to be used as raceways for wiring associated with instrument transformers and energy usage metering devices, subject to the following: Each enclosure must be approved to house these devices, and The wiring does not fill the wiring space to more than 75% of the cross-sectional area of the space. British Columbia Safety Authority,

29 Section 14 Protection and Control Rule Rating of overcurrent devices (see Appendix B) Subrule (2) has been added to restrict the allowable overcurrent protection of sizes #14, #12 and #10 copper to 15 A, 20 A and 30 A respectively. #12 aluminum is restricted to 15 A, #10 aluminum is restricted to 25 A by way of a Feb 6 th errata from CSA. This Subrule and the restriction have been added to ensure that Users of the Code understand the new ampacity tables and the required protection as well as provide minimum safety requirements when these common conductor sizes are used. The reference to Subrule (1) (c) as provided by other Rules of the Code refers to Rules which specifically permit sizes # 14, # 12 and #10 conductors to have O/C protection greater than the protection required by items (a), (b), and (c). Rules regarding the protection of conductors supplying capacitors, transformers, motors, arc welders, and similar equipment would qualify under this provision. (2) Except as provided by Subrule 1(c), the rating of overcurrent protection shall not exceed (a) 15 A for No. 14 AWG copper conductors; (b) 20 A for No. 12 AWG copper conductors; (c) 30 A for No. 10 AWG copper conductors; (d) 15 A for No. 12 AWG aluminum conductors; and (e) 25 A for No. 10 AWG aluminum conductors British Columbia Safety Authority,

30 Rule Use and rating of manually operated general-use AC switches (see Appendix B) Subrule (1) has been revised to clarify the ampacity requirements for general purpose AC switches. Subrule (2) requires general purpose AC switches be specifically approved for the purpose and so marked. Section 16 Class 1 and Class 2 Circuits Rule Insulated Conductors for Class 1 Wiring Subrule (1) has been revised to direct the user to Rule (Table 19). The conductor(s) selected shall be specified in Table 19 for the specific condition of use and shall be suitable for the particular location with respect to moisture, corrosion, temperature, etc Conductors for Class 2 circuit wiring (see Appendix B) Subrule (1) has been revised to require that conductors for use in Class 2 circuits are of a type suitable for the application as indicated in Table 19 and selected in accordance with Rule (1). Where conductors smaller than No. 14 AWG are permitted, use of equipment wire types REW, SEW-1, SEWF-1, TEW, and TEWN shall be permitted provided that the equipment wires are installed in raceways. British Columbia Safety Authority,