- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
The panel is considering a fairly impressive leap in the sizing of EGCs installed in parallel.
1.) Comment on Proposal No.: 5-201a
2.) Recommendation: Continue to accept this proposal.
3.) Substantiation: This proposal makes a fundamental change to 250.122(F), allowing individual parallel EGCs to be smaller than previously allowed, except if 250.122(A) was seen to override 250.122(F). This is a sensible change and should be accepted into the 2014 NEC.
Proposal 201a said:Submitter: CMP-5
Recommendation: Revise 250.122(F) to read as follows:
(F) Conductors in Parallel. Conductors installed in parallel shall have equipment grounding conductors installed in accordance with (1) or (2). Each equipment grounding conductor shall be sized in compliance with 250.122.
(1) If conductors are installed in multiple raceways or cables as permitted in 310.10(H), wire-type equipment grounding conductors, if installed, shall be in parallel in each raceway or cable and shall not be required to be larger than the largest ungrounded conductor installed in each raceway or cable.
Exception: Under engineering supervision in industrial locations...
(2) If conductors are installed in the same raceway, cable or cable tray as permitted in 310.10(H), a single equipment grounding conductor shall be permitted. Equipment grounding conductors installed in cable tray shall meet the minimum requirements of 392.10(B)(1)(c).
Substantiation: The revision separates the two conditions of multiple raceways or cable and single raceways or
cables. The revised text provides better clarity and usability to the installers and inspectors. The text was also revised
to clarify that for feeders or branch circuits where the equipment grounding conductor in the raceway could become
larger than the ungrounded conductors, the equipment grounding conductor is not required to be larger than the
enclosed ungrounded conductor. This makes this provision consistent with 250.122(A) where it was not clear which
section took precedence. The new exception allows industrial installations which are designed under engineering
supervision to utilize standard cables applied in parallel. The exception also includes similar provisions for raceways.
1.) Comment on Proposal No.: 5-201a
2.) Recommendation: Continue to accept this proposal.
3.) Substantiation: This proposal makes a fundamental change to 250.122(F), allowing individual parallel EGCs to be smaller than previously allowed, except if 250.122(A) was seen to override 250.122(F). This is a sensible change and should be accepted into the 2014 NEC.
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