National Electrical Installation Standards

Standards as High as Your Own

Wednesday, February 19, 2020


Hello all, we were having a discussion in the office about 110.24 Available Fault Current.

The code section seems kind of vague, as where the available Arc Fault Sticker should be placed. I said it should be placed at the switch-gear because that's where the first means of disconnect is. They say at the ct cabinet.

What say ye?

- Tom Labee



Hi Tom, thanks for the questions.

Section 110.24 requires service equipment at other than dwelling units shall be legibly marked in the field with the maximum available fault current. The Code does not require a sticker or label in this rule, although this is a common method of meeting the requirement. Because the marking is required at the "service equipment" this can include various locations. It seems logical that the marking would be at the service disconnecting means enclosure, but the Code is not specific.

Perhaps this is an opportunity for a public input to narrow this down for users like yourself. Visit to submit your Public Input.

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