Ask an electrical safety officer: Working on a duplex meter base

Is it permissible to enter cables into the back of a duplex meter base for the feeder to a panelboard?  This involves creating an opening that is not provided for by the manufacturer through a pre-determined knockout location. 


Cables are not permitted to enter the back of a meter base unless it has approved knockout locations provided, or if those additional holes are approved by the manufacturer.

Manufacturers supply approved knock out locations which allow for the safe termination of raceways and connectors for service conductors. The testing methods provided by the manufacturer take into account the bending radii of conductors and various termination installation methods used by both the utilities and the installer.

Rule 2-024 of the BC Electrical Code outlines the use of approved equipment. “Electrical equipment used in electrical installations within the jurisdiction of the inspection department shall be approved and shall be of a kind or type and rating approved for the specific purpose for which it is to be employed.”

 

What types of conductors are permitted for consumer service conductors? These are conductors installed from the meter base to each individual service entrance panel or service disconnect. The photo shows that the aluminum non-metallic sheathed cable was installed for the consumer service conductors to the suite and main home service entrance panel. 


Consumer service conductors are not protected between the meter base and service entrance panel. See Directive: BC Electrical Code Section 6 - Services and Service Equipment regarding requirements for this type of installation. 

Consumer’s service conductors are interpreted as entering a building where the raceway or cable penetrates any part of the building envelope, or where the raceway or cable emerges from concrete encasement.

This rule is interpreted as requiring consumer’s service equipment to be located so that the length of consumer’s service conductors, inside the building, is as short as possible.

In no case, shall consumer’s service equipment be located so that the length of consumer’s service conductor, inside the building, exceeds 1.5 m. The 1.5 m is determined by measuring the length of raceway or cable between the point where the raceway or cable enters the building and the point where the raceway or cable enters the service box or cabinet.

The use of non-metallic sheathed cable is not permitted as a consumer service entrance cable. The following entries in the BC Electrical Code support the types of conductors and installation methods permitted:

  • Table 19 provides an overview of insulated conductors used for electrical installations must be suitable for the location (e.g., dry, damp, wet, or hazardous locations) and suitable for the conditions of use (e.g., direct earth burial, exposed or concealed wiring methods, in raceways, and for service entrance use).
  • Rule 12-100 
    “Conductors installed in any location shall be suitable for the condition of use as indicated in Table 19 for the particular location involved and with particular respect to (a) moisture, if any; (b)corrosive action, if any; (c) temperature; (d) degree of enclosure; and (e) mechanical protection.”  
  • Rule 6-302 
    (1) Conductors of a consumer’s service that are located above ground, at any point, on a building or other structure shall be installed in one of the following ways:
    (a) rigid conduit;
    (b) busway;
    (c) steel electrical metallic tubing;
    (d) flexible metal conduit, with lead-sheathed conductors;
    (e) mineral-insulated cable other than the lightweight type;
    (f) aluminum-sheathed cable or copper-sheathed cable;
    (g) Type ACWU75 or Type ACWU90 cable;
    (h) Type AC90 cable; or
    (i) Type TECK90
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