National Electrical Installation Standards

Standards as High as Your Own

Wednesday, November 7, 2018


I currently have 220 vac - 2 wire Aluminum Service Entrance Cable with AL braid from the service transformer outside to a 600A disconnect inside (basement) The AL braid is used as the neutral conductor which I understand is acceptable from the transformer to the Disconnect. My question is .......Is it acceptable to use Aluminum Service Entrance Cable and the AL braid .From the Disconnect to the Service Panel or should the neutral be an insulated conductor. Service cable runs are in non-metallic conduit.

Thanks, John Barkley



Hey John thanks for your question. Aluminum service entrance grounded conductors (usually also neutral conductors), that are part of a cable assembly (such as SE-U), are allowed to be uninsulated as stated in 230.41Exception (4). The disconnect inside the basement is your service equipment, if I understand your example correctly, the conductors from it to a panelboard are feeders. See the definitions of Service Entrance Conductors, Underground System, Grounded Conductor, Neutral Conductor, and Service Equipment in Article 100 to help explain those terms. Grounded conductors that are part of Service Entrance Cable - Type SE used for feeders and branch circuits must be insulated (such as SE-R) as stated in 338.10(B)(1). Type SE cable is also not allowed underground - whether or not in a raceway, as stated in 338.12(A)(2). Make sure you are not using USE cable because it is not allowed inside buildings as stated in 338.12(B), unless it is also marked with another insulation type that is suitable.

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