Small conductors

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Is there a code that states you must pull a #10 ground with other #10 wires in the same raceway? I have been taught that if you are pulling #10 ungrounded conductors for voltage drop and landing them on a 20a breaker you must use a #10 ground. At my new job the boss is telling me this is not true, a number 12 is all you need for a 20a circuit.
 
Welcome to the Forum and have him read this.

250.122 Size of Equipment Grounding Conductors.
(B) Increased in Size. Where ungrounded conductors are increased in size, equipment grounding conductors, where installed, shall be increased in size proportionately according to the circular mil area of the ungrounded conductors.
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CK is correct, that's what it says. Your AHJ may or may not enforce that one.

How about this: I was going to use 1/2" EMT with a #12 circuit on a 20 amp breaker. EMT would be the equipment grounding conductor. But then I decide to use #10 circuit conductors. I guess I have to increase the pipe size to 3/4"? :cool:
 
crossman said:
How about this: I was going to use 1/2" EMT with a #12 circuit on a 20 amp breaker. EMT would be the equipment grounding conductor. But then I decide to use #10 circuit conductors. I guess I have to increase the pipe size to 3/4"? :cool:
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Good point Gary. But you only have to increase to ?" IMC in that case.:roll:

You gotta love a 120V fault an a 20A breaker at 200'. Listen to the conduit sing! Whats that, about 120 cycles?:)
 
If I have a EMT conduit, 20 amp circuit, on # 10 wire and pull a # 12 ground this is a violation. To comply with code I can remove the # 12 ground and now I am legal. Which is better leave the # 12 ground and use the raceway or remove the #12 and use the raceway only?
 
jamesoftn said:
If I have a EMT conduit, 20 amp circuit, on # 10 wire and pull a # 12 ground this is a violation.
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Yes.

To comply with code I can remove the # 12 ground and now I am legal.
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Yes.

Which is better leave the # 12 ground and use the raceway or remove the #12 and use the raceway only?
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I guess best would be to replace the 12 EGC with a 10 EGC, but leaving the 12 AWG EGC is a code violation.
 
The code rules are prescriptive, and are intended to work regardless if its 1/2" EMT or PVC. Since EMT is considered a EGC per 250.118, and you are installing an EGC, then you are saying that the EMT is not reliable as an EGC (workmanship or damage), and in that case you follow 250.122.
 
I was taught to legally size the egc that you use a ratio formula, buy dividing the original conductor into the new increased conductor, that would give you the ratio to multiply by the cms of the original egc for the new upsized egc, was wondering if theres any other formulas ppl use besides this?
thanks
 
This is rediculous. They let manufacturers get away with less and less and less and force us to install redundant nonsence at great cost increase and I guarantee you probably only a few out of every hundred electricians will comply. A coil of 10 wire is about 125 bucks what a waste.
 
crossman said:
CK is correct, that's what it says. Your AHJ may or may not enforce that one.
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If not, then the AHJ is not doing his or her job properly. This isn't an optional thing; the code leaves no room for AHJ interpretation here.
 
quogueelectric said:
. . . I guarantee you probably only a few out of every hundred electricians will comply.
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I do hope you are wrong about this. I would prefer to think that 99 out of 100 electricians will do what the code says to do, even if it does not make sense. This requirement, however, does make sense, at least to me.
 
crossman said:
How about this: I was going to use 1/2" EMT with a #12 circuit on a 20 amp breaker. EMT would be the equipment grounding conductor. But then I decide to use #10 circuit conductors. I guess I have to increase the pipe size to 3/4"? :cool:
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I think not, but someone with an NEC handy (I am not near my copy at the moment) will have to check me on this one.

Look at the quotation Chris posted in reply #2, and especially at the words, ". . . the (EGC), where installed. . . ."

We all know that a raceway is sometimes permitted to serve, in lieu of a wire, as the path for fault current. But is the raceway actually called an "equipment grounding conductor"? Does a conduit or a SMR actually fit the definition of "conductor"? My guess is that it is not, and it does not. So in the situation crossman has described, the EGC is not "installed," so it need not be "increased in size."
 
I personally do not use an egc in conduit where I do not have to. I think it is a pretty hefty increase in work and cost.

Apparently the authors of the NEC don't think it's necessary, and neither do I.

I don't quite get why you'd squawk about using an increased size, when it's use is entirely at your discretion...you don't have to use nothin' at all.

This is from the OKonite cable page:

Grounding Conductor: Where indicated, bare soft annealed copper, Class B stranded in accordance with UL 1581. Meets or exceeds requirements of NEC Table 250.122.
 
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iwire said:
Your point?

I stand by what I said above.
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...and I stand by there with you.

Yours just happened to be the last post I read in the string.

It seems to me that the prevelant argument is that the NEC does not allow reduction of EGC. It seems that Okonite and all the other cable manufacturers are marketing cables that do not meet that requirement as they start reducing the EGC sizes at larger sizes.

Any comments?
 
charlie b said:
But is the raceway actually called an "equipment grounding conductor"? Does a conduit or a SMR actually fit the definition of "conductor"? My guess is that it is not, and it does not.
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250.118(4) says it is
 
The cable manufactures make their EGC compliant when the cable is used at its ampacity. This is no different than when you try to use a cable for a parallel installation...unless you order custom cable the EGC will be too small.
 
mivey said:
250.118(4) says it is
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What many people are unaware is the fact that conduits have a limitation on current carrying capability and are tested for that. Under duress they will supply you with a chart on how long a conduit run can be for a certain circuit size and still be considered an EGC. I don't know how many fittings and intermediate JB's can you have on such run, since the test is just done in the lab and simple couplings are installed.

Also should consider the fact that in a wet, outdoor, environment corrosion will eventually takes place which degrades the conductivity of the threaded coupling, therefore reduces the current in case of a ground fault, eventually resulting in a no-trip situation and potential fire.

Our Standards call for a grounding condutor to be run with all circuits.
 
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