Directive: BC Electrical Code Section 4 - Conductors

This Directive is being issued by a provincial safety manager pursuant to section 30 of the Safety Standards Act.

4-004 Ampacity of wires and cables (see Appendix B)

Subrule 1) f):

1) The maximum current that a copper conductor of a given size and insulation is permitted to carry shall be as follows:

“underground configurations in conductor sizes smaller than No. 1/0 AWG, as specified in Item (b) or as calculated by the IEEE 835 calculation method”
TABLE 2

Subrule 2) f):

2) The maximum current that an aluminum conductor of a given size and insulation is permitted to carry shall be as follows:

“underground configurations in conductor sizes smaller than No. 1/0 AWG, as specified in Item (b) or as calculated by the IEEE 835 calculation method”
TABLE 4

Interpretation:

When the ampacity of a conductor is selected in accordance with item f) and subsequently increased in size to a conductor #1/0 or larger to meet voltage drop requirements, the conductor may be installed in compliance with Rule 12-012.

Subrule 22):

“Notwithstanding Rule 4-006, 3-wire 120/240 V and 120/208 V service conductors for single dwellings and feeder conductors supplying single dwelling units of row housing of apartment and similar buildings and terminating on equipment having a conductor termination temperature of not less than 75 °C shall be permitted to be sized in accordance with Table 39.”

Interpretation:

1. For the purpose of rule 4-004 22), the requirements of rules 4-004 1) and 4-004 2) need not apply. Service conductors and feeder conductors selected in accordance with this sub-rule are permitted to be installed in accordance with rule 12-012.
2. Table 39 is interpreted to include service and feeder conductors supplying a single dwelling and feeder conductors supplying single dwelling units of row housing of apartment and similar buildings.
3. Table 39 shall not apply when parallel conductors are used to supply service or feeders for single dwellings and feeder conductors supplying single dwelling units of row housing of apartment and similar buildings.
4. Feeder conductors supplying a subpanel from the main service of a single dwelling need not be of a greater ampacity than the main service conductor, provided that the load to the subpanel does not result in an increase to the main service demand and the main service conductors have been sized in accordance with Subrule 22).

 

Provincial Safety Manager

References:
Safety Standards Act
Electrical Safety Regulation
Safety Standards General Regulation