Temporary wiring
Scope
(1) Section 76 of the BC Electrical Code (BCEC) covers temporary wiring installations for buildings or
projects under construction or demolition and experimental or testing facilities of a temporary nature.
(2) The requirements of Section 76 supplement or amend the general requirements of the BCEC.
Section 76 includes additional and specific requirements for temporary electrical installations
used to provide power for lighting, power, tools, heating, etc. in building structures or other
premises that are under construction or demolition. Section 76 also specifies requirements
for temporary electrical installations used to provide power for temporary experimental or
testing facilities and similar short-duration installations. The wiring methods for permanent
electrical installations are often impractical, and in some cases impossible, to follow in
temporary installations, where wiring methods need to be
• portable;
• flexible; and
• easily modified.
Temporary installations present a different environment to that of permanent installations.
For example, the required use of extra-hard-usage flexible cords offer additional
flexibility/durability features than the cable used in a permanent installation.
Conductors
(1) Conductors shall be
(a) of a type in accordance with Section 12 of the BCEC; or
(b) power supply cable or flexible cord of the outdoor type suitable for extra-hard usage.
(2) Conductors shall be insulated.
(3) Service conductors shall be installed in accordance with Sections 6, 10, and 36 of the BCEC.
(4) Overhead conductors shall be aerially supported on poles or other equally substantial means with the
spacing of supports not to exceed the maximum span length allowable for the type of conductors used.
(5) Electrical cords with broken/frayed insulation, missing ground prongs must not be used.
As temporary wiring can be subjected to excessive abuse and severe environmental
conditions, conductors be
• the appropriate type for the conditions of use specified in Section 12 of the BCEC;
• portable power supply cables of the extra-hard-usage outdoor type; or
• flexible cords of the extra-hard-usage outdoor type.
The requirements for bare neutral conductors in services (see Rule 6-308) and grounding
conductors (see Rules 10-802 and 10-806) apply to temporary wiring electrical installations.
Overhead conductors are often used on construction and demolition sites to keep the
conductors out of the way of machinery and operations. Where overhead conductors are
used, Subrule (4) requires the use of suitable supports, spaced at intervals that do not
exceed the distances allowed in Rules 12-308 and 12-318 for the type of overhead
conductor being used.
‐ 2 ‐ 76-004 Grounding and bonding
All grounding and bonding shall be in accordance with Section 10.
A reliable grounding and bonding system is required on a temporary installation to provide
protection against shock hazards and to allow overcurrent devices to perform their
necessary function of clearing faults on the system. All bonding and grounding be in
accordance with Section 10 of the BCEC.
76-006 Service entrance equipment
Where the service equipment is installed in an outdoor location, the equipment shall
(a) be accessible to authorized persons only;
(b) be capable of being locked;
(c) be protected against weather and mechanical damage; and
(d) not exceed 200 A where mounted on a single pole.
Service entrance equipment, especially in temporary installations, must be in a location that
is free from environmental hazards, moving equipment, and other operations that might
have an impact on equipment performance. If this equipment is damaged, fire or shock
hazards can result. Because a large number of people often work in the immediate vicinity
of electrical equipment on a construction or demolition project, and in some cases work in
adverse conditions, there is an increased probability that a fault condition in improperly
located or maintained service equipment will create an electrical shock hazard.
Service entrance electrical equipment located outdoors be
• inaccessible to unauthorized personnel;
• lockable, to prevent access by unauthorized personnel, especially after working hours;
• protected from weather and mechanical damage; and
• where mounted on a single pole, no larger than a 200 A service (a 200 A service is too
heavy and/or large for single-pole support.
Figure 76-1 illustrates a typical installation.
‐ 3 ‐ Figure 76-1
Typical temporary service installation
76-008 Distribution centres
(1) Distribution centres shall have a sufficient number of branch circuits and be of adequate capacity to serve the
connected load without overloading any branch circuits and without violating the requirements of Section 14 BCEC.
(2) Distribution centres shall be installed in a weatherproof building or be of weatherproof construction.
(3) Distribution centres including portable ones shall be mounted in an upright position.
Distribution equipment must be suitably located and maintained. It is generally used to
connect electrical tools and equipment by a variety of workers, some of whom are not
trained or qualified in the use of electrical distribution equipment. It is also subject to misuse
after working hours, as work sites are often not well secured. Damage to a distribution
centre can create fire and shock hazards.
Rule 76-008 requires that distribution electrical equipment be
• located in a weatherproof building or in a weatherproof enclosure;
• mounted in the erect position; and
• of adequate size and with sufficient branch circuits for the types and sizes of loads that
will be connected to it.
Distribution centres must also be protected from mechanical damage and controlled by a
disconnecting means that is protected by an overcurrent device. Figure 76-2 shows a typical
installation.
‐ 4 ‐ Figure 76-2
Indoor temporary distribution centre
76-014 Interconnections
Temporary installations shall be constructed as separate installations and shall not be interconnected with
any of the circuits of the permanent installations except by special permission.
Temporary electrical installations must not be connected to the permanent circuits of a
building so that a circuit cannot be energized by two separate power sources (the temporary
and the permanent source). Such connections present a shock hazard to workers who might
think the new installation is not connected to a power source.
Rule 76-014 allows exceptions by special permission from the inspection department.
These exceptions are limited to certain clearly marked circuits, and before the permanent
power source is energized, the temporary supply must be removed.
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76-016 Receptacles
Receptacles having CSA configuration 5-15R or 5-20R installed to provide power for buildings or projects
under construction or demolition shall be protected by ground fault circuit interrupters of the Class A type.