338.2 Definitions.
Code Change Summary: New code definition of a Service-Entrance Conductor Assembly.
In the 2020 NEC®, a new definition was added to address service-entrance conductor assemblies without any covering. In a Service-Entrance Conductor Assembly, the individual conductors themselves are insulated and twisted together but the conductor assembly does not have an overall outer covering like an SE or USE cable does.
There are several types of service-entrance cables, each with their differences:
- USE cable is an underground rated service-entrance cable with a moisture-resistant outer covering that is not required to be flame-retardant.
- SER or SE Style R cable has an outer flame-retardant, moisture-resistant covering and usually has a separate bare equipment grounding conductor.
- SEU or SE Style U cable has the individual strands of a bare conductor wrapped around the insulated conductors.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC® edition of NFPA 70.
2017 Code Language:
338.2 Definitions.
Service-Entrance Cable. A single conductor or multiconductor assembly provided with or without an overall covering, primarily used for services, and of the following types:
Type SE. Service-entrance cable having a flame-retardant, moisture-resistant covering.
Type USE. Service-entrance cable, identified for underground use, having a moisture-resistant covering, but not required to have a flame-retardant covering.
2020 Code Language:
338.2 Definitions
Service-Entrance Cable. A single conductor or multiconductor cable provided with an overall covering, primarily used for services, and of the following types:
Type SE. Service-entrance cable having a flame-retardant, moisture-resistant covering.
Type USE. Service-entrance cable, identified for underground use, having a moisture-resistant covering, but not required to have a flame-retardant covering.
N Service-Entrance Conductor Assembly. Multiple single-insulated conductors twisted together without an overall covering, other than an optional binder intended only to keep the conductors together.