CURRENT TRANSFORMER CABINET

The customer provides and installs a cabinet for the current transformers, and the conduit between the CT cabinet and the meter enclosure. The CT cabinet is metal, weather tight, NEMA 3R rated, and securely mounted on a rigid surface plumb in both directions. The cabinet is to have a side-hinged, sealable door. When open, the door must not block a safe exit.

The top of the cabinet must be no higher than 7 feet above the floor, and the bottom of the cabinet must be at least 6 inches above the floor. The dimensions of the CT cabinet are:

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                                                             Number                     Cabinet
  Service                                             of CTs         Width       Height          Depth
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Single-phase, 400-800 amps             2                    30"           48"                 11" 
Three phase, 200-800 amps              3                   36''           48''                11''
Over 800 amps                                Requires switchboard metering

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The location of the CT cabinet is subject to the approval of the power company.

Inside the cabinet, the customer installs a mounting base for the CTs. A single-phase mounting base is used if the service is single-phase, a three-phase mounting base is used if the service is three-phase. The base has two cable termination bolts on the line and the load side of each phase, and two bolts on the neutral bus.

The CT cabinet contains only the main service conductors. A maximum of four main service conductors may be served from the load side of each termination bolt, as long as the lugs are not stacked and do not restrict mounting the CTs. Use "stair step" lugs if more than two conductors are terminated at a CT.

If the CT cabinet is installed in a vehicle traffic area, install a guard post.

Meter Socket, Enclosure, and Conduit

The distance between the meter socket enclosure and the CT cabinet is not less than 10 inches and not more than 50 feet. Mount the two enclosures as close together as feasible.

Meter Socket and Enclosure for Single-Phase Circuits
For single-phase circuits, the customer provides and installs a 6-terminal meter socket in an enclosure, with conduit between the meter enclosure and the CT cabinet.

Meter Socket and Enclosure for Three-Phase Circuits
For three-phase circuits, the customer provides and installs a 13-terminal meter socket in an enclosure, with conduit between the meter enclosure and the CT cabinet

Conduit
For conduit, use rigid steel, rigid PVC plastic (Schedules 40 or 80), or IMC/EMT conduit. Flex conduit is not permitted. When metallic conduit is used, provide grounding bushings at each end. When PVC conduit is used, install a green insulated bonding jumper in the conduit. 1-1/4-inch conduit or larger is required, with proper fittings and bushings to protect metering conductors.

The conduit enters the meter enclosure adjacent to the test switch.

A pull cord is required if the conduit is over 25 feet. Conduit bends must not exceed 360 degrees total.