Code Change Summary: Aluminum conductors are now included in Table 312.6(A).

NEC Table 312.6(A) provides minimum wire-bending space dimensions at terminals and minimum width of wiring gutters. Table 312.6(A) applies where conductors do NOT enter or leave the enclosure through the wall opposite their terminals.

According to 110.5, “where the conductor material is not specified, the material and the sizes given in this Code shall apply to copper conductors”. In the 2014 NEC^®, Table 312.6(A) only applied to copper conductors since the conductor material in the table was not mentioned.

If an electrician wanted to install a gutter box with 8 AWG or larger aluminum conductors terminating in the box and leaving the box at a point other than the opposite wall where they terminate, there was no direction given in the code on any minimum dimensions.

Table 312.6(B) applies where conductors enter or leave the enclosure through the wall opposite their terminals and has included provisions for both copper and aluminum conductors since the 2002 edition of the NEC^®.

In the 2017 NEC^®, Table 312.6(A) was revised to include bending space for aluminum conductors. This was the result of a fact-finding investigation initiated in 2015 that included bend testing of aluminum conductors to ensure that the conductors did not sustain damage that would compromise the conductors or insulation.

Below is a preview of Article 312. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2017 NEC^® edition of NFPA 70.

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