Code Change Summary: New code language was added to clarify how direct current (DC) feeders must be identified.

Prior to this code change, the NEC^® only provided rules on how to identify ungrounded feeder conductors in an alternating current system but not a direct current system.

Now, specific identification methods are required for ungrounded DC feeders.

The rules apply when a feeder is supplied from a DC system operating at more than 50 volts. If the ungrounded DC feeders are 4 AWG or larger, they must be identified by polarity at all termination, connection, and splice points by marking tape, tagging, or other approved means.

If the ungrounded DC feeders are 6 AWG or smaller, they must be identified by polarity at all termination, connection, and splice points in compliance with 215.12(C)(2)(a) and (b).

Here are a few things to remember when applying the DC feeder identification rules:

• More than 50 volts does not include 50 volts. More than 50 volts means 50.5 volts or more.
• 6 AWG or smaller includes size 6 AWG and does not ONLY mean conductors smaller than 6 AWG.
• 4 AWG or larger includes 4 AWG and does not ONLY mean conductors larger than 4 AWG.

Below is a preview of the NEC^®.  See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on the “free access” tab and select the applicable year of NFPA 70 (National Electrical code).

See NEC^® 215.12(C)(2)(a) and (b) for allowable identification methods of ungrounded DC feeders size 6 AWG or smaller.