EGC size in Conduit

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mbrooke

mbrooke

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When running running dedicated EGCs to circuits in conduit, can table 250.122 be used without having to up-size them to the largest circuit?
 
I believe so. The branch circuit EGC must be sized per the overcurrent device rating and any factor for conductor oversize due to voltage drop. A common application for this is isolated ground receptacles where each gets it own dedicated EGC. If not isolated ground EGC's, watch the rules for splices in boxes -- all must be connected together if they are spliced.
 
suemarkp said:
I believe so. The branch circuit EGC must be sized per the overcurrent device rating and any factor for conductor oversize due to voltage drop. A common application for this is isolated ground receptacles where each gets it own dedicated EGC. If not isolated ground EGC's, watch the rules for splices in boxes -- all must be connected together if they are spliced.
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What do you mean all must be connected together if spliced?
 
You can pass them through unspliced if you wish. But if a circuit splits and is therefore spliced, all grounds that got spliced must be connected.

For example, lets say there are 4 circuits in the conduit. Two pass through a junction box unspliced and two others split left and right to go to multiple locations. So the 6 spliced grounds (two incoming and 4 outgoing) must be all connected together. The unspliced ones can remain unspliced.
 
petersonra said:
I think they are afraid that in changing it they will make it worse as has happened many times in the past.
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I think they need something like a committee of English majors to write/ review the wording - or... I don't know, it just blows my mind some of the ridiculous wording they come up with and everyone involved thought it was fine.
 
The purpose of an equipment grounding conductor is to clear a fault. As you know there is no current normally running ion the equipment grounding conductor so what does it matter if it were in parallel.
 
So if I have a number 6, 10 and 12 all need to be put under a split bolt in every j-box and then the box needs to be bonded with a #6?
 
If you've spliced each of them, then yes. If this is just a pull box or a direction change and you can pull all or some the grounding wires in and out without splicing, then no splice required for the ones passing through (assuming the box is adequately bonded with a metallic wiring method - otherwise you need to splice or tap the largest one to bond the box).

Not sure if a split bolt is legal for 3 wires and that size mix though.
 
suemarkp said:
If you've spliced each of them, then yes. If this is just a pull box or a direction change and you can pull all or some the grounding wires in and out without splicing, then no splice required for the ones passing through (assuming the box is adequately bonded with a metallic wiring method - otherwise you need to splice or tap the largest one to bond the box).

Not sure if a split bolt is legal for 3 wires and that size mix though.
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Largest one- that makes sense :)
 
mbrooke said:
So if I have a number 6, 10 and 12 all need to be put under a split bolt in every j-box and then the box needs to be bonded with a #6?
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If the 6 and 10 are for 20 amp circuits but are sized because of voltage drop, you should be able to make a #12 pigtail to the box. Otherwise yes in general pigtail would normally need to be no smaller than the largest conductor it connects to.
 
petersonra said:
You can run them in parallel but you can't run parallel conductors to make up an egc.
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I agree can have all sorts of paralleling involved, even with metal raceways, but can't run them parallel with intent of creating effectively larger conductor. NO 1/0 minimum either like for other conductors in that are in parallel for the purpose of creating a larger overall conductor.
 
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