Equipment Grounding Conductors

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Kent Haller

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Columbus OH
If you use the conduit system as your equipment grounding conductor, and have a wire ground installed as well, is the wire ground required to be sized per tabel 250.122?
 
Yes, better, but not compliant. Go figure. The thought seems to be either do it right or don't do it.
 
One would have thought a better way to word
250.122 Size of Equipment Grounding Conductors.
(A) General. Copper, aluminum, or copper-clad aluminum
equipment grounding conductors of the wire type shall not be
smaller than shown in Table 250.122 ...
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would be something like

250.122 Size of Equipment Grounding Conductors.
(A) General. Where copper, aluminum, or copper-clad aluminum
equipment grounding conductors of the wire type is the only EGC,
the wire shall not be smaller than shown in Table 250.122 ...

My guess is that was probably the original intent but it got mucked up and now fixing it is all but impossible.
 
Incidentally, it is pretty common for people to violate this rule.

Think about a conduit that has both a 20A and a 15A branch circuit. If the electrician ran a #14 ground and a #12 ground he would be in violation, but would be Ok if he ran just a #12, or none at all if it was metal conduit.

Could I have 2 TCs in a tray, one a 20A circuit with a #12 EGC and the other a 15A circuit with a #14 EGC inside the respective TC?
 
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petersonra said:
Think about a conduit that has both a 20A and a 15A branch circuit. If the electrician ran a #14 ground and a #12 ground he would be in violation, but would be Ok if he ran just a #12, or none at all if it was metal conduit.
Click to expand...

Care to explain this?
 
i don't rely on pipe as a ground unless it's rigid. i was taught this way, yes, it's legal and meets code, but i won't install like this. an egc is always pulled. i've seen way too much emt installed in an obvious hurry, then , in trying to fish it later, it comes apart at connectors!
:rant:
 
petersonra said:
Incidentally, it is pretty common for people to violate this rule.

Think about a conduit that has both a 20A and a 15A branch circuit. If the electrician ran a #14 ground and a #12 ground he would be in violation, but would be Ok if he ran just a #12, or none at all if it was metal conduit.

Could I have 2 TCs in a tray, one a 20A circuit with a #12 EGC and the other a 15A circuit with a #14 EGC inside the respective TC?
Click to expand...


Code reference please.
 
petersonra said:
250.122 I think. It says what size EGCs have to be.
Click to expand...

In your rather interesting question you have 2 EGC's in one raceway. 250.122(C) addresses a single EGC.

250.122(C) Multiple Circuits.

Where a single equipment grounding conductor is run with multiple circuits in the same raceway, cable, or cable tray, it shall be sized for the largest overcurrent device protecting conductors in the raceway, cable, or cable tray. Equipment grounding conductors installed in cable trays shall meet the minimum requirements of 392.3(B)(1)(c).
Click to expand...
 
For multiple GEC's in a raceway I see no reason why you can't have a #14 for the 15 amp circuit and a #12 for the 20 amp circuit. They can even be spliced together at the junction box.
 
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