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Joined: Mar 2004
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BigB Offline OP
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I don't follow you, the nameplate MCA gives us the permission to size the wire accordingly. Also, 250.122 says #12 EGC for an OCPD not exceeding 20 amps. 25 amps exceeds 20 amps, and puts us into #10, (which is good up to 60 amps) is the way I am reading it.

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Joined: Jun 2004
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BigB, Hotline...Ok I understand what your getting at now. Sorry for being slow to pick up on the grounding issue. It appears that your interpretation of the EGC sizing is in line with article 250.122 in your situation. Good catch.

Joined: Jun 2004
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Originally Posted by renosteinke
Please note that the 2014 edition will have changes to this requirement in air conditioning article.


What specific changes are we looking at?

Joined: Jan 2005
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Cat Servant
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From the thread "Let the Diss-CUSS-ion Begin:"

"7) Certain uses of EMT outdoors will be required to have a ground wire. This gem is buried in Article 440."

I haven't seen the text, but I'll be sure to look closely at AC grounding when it comes out! Heaven alone knows what other grounding changes are buried in the text.

I've been with ECN for several code cycles, and every new edition seems proceeded by threads where our learned discussion is torn apart by new code changes a few months later. This might be just such a thread.

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G
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Sorry I am late on this but Short Circuit pointed out 250.122 says you do not need to exceed the circuit conductor size for the EGC, so if the circuit can be #14, the EGC can be #14.

Quote
250.122(A) Copper, aluminum, or copper-clad aluminum
equipment grounding conductors of the wire type shall not
be smaller than shown in Table 250.122, but in no case shall
they be required to be larger than the circuit conductors supplying
the equipment.


I am not seeing anything that contradicts this and requires more than #14 if the circuit conductors are #14.
If there is a fault, why should the EGC need to be be any bigger than the circuit feeding the fault?

But I would not let them use type NM to wire a condenser (wet location). If it was UF it would be OK but that is still going to be in a raceway in my patch.


Greg Fretwell
Joined: Jun 2004
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Finally some support on my interpretation...although this discussion has confused me on which is correct.

I referred to my Soares book on grounding and it supports that the EGC never has to be larger than the circuit conductors.

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G
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It is certainly logical. Why would the return path for a fault ever have to be bigger than the supply?

This all gets back to the difference between overload and overcurrent.


Greg Fretwell
Joined: Jul 2007
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Per OP, 14 gauge wire and 25 amp breaker. I'd pull a ground every time required or not. My license, my butt, my problem and I sleep peacefully at night.


"Live Awesome!" - Kevin Carosa
Joined: Jul 2007
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Originally Posted by gfretwell
It is certainly logical. Why would the return path for a fault ever have to be bigger than the supply?

This all gets back to the difference between overload and overcurrent.
I agree with Greg on both accounts. 25 Amp breaker is motor class 101. To prevent neuscuence tripping on startup. And possibliy overload protection to in this case. The ground does not have to be any bigger than the grounded conductor if the circuit is sized right. The grounding conductor carries a fault for only a split second. It will get warm and carry more that enough current to trip the breaker in the event of a ground fault. You can run a 3/0 grounding conductor with 3/0 circuit if you want but if the breaker but in a ground fault where the breaker fails, that 3/0 will burn up too just like a #6 will so why install more then needed


"Live Awesome!" - Kevin Carosa
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BigB Offline OP
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Originally Posted by shortcircuit
Finally some support on my interpretation...although this discussion has confused me on which is correct.

I referred to my Soares book on grounding and it supports that the EGC never has to be larger than the circuit conductors.


I am in complete agreement with your interpretation, I did not mean to confuse the issue by contesting Hotline's selection of the EGC size (even though selection is not needed per your interpretation).

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