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-   -   Ground connection / Bonding in EMT (http://www.diychatroom.com/f18/ground-connection-bonding-emt-38648/)

jamiedolan 02-18-2009 09:18 PM

Ground connection / Bonding in EMT
 
HI;

This has happened to me, with 10awg, and I wasn't positive what to do, so I pigtailed and bonded with the 10awg ground. I think I am going to run into the same issue in my house, but will likely have a 6awg ground in the conduit, becuase I have been pulling a 6awg for the fault path for sub panels, I know it is more than is required, but I have 6, I have 10 also... But I would still like to know the proper way to do this regardless of the gage.

If I have a pull box that has multiple conduits in it and I have a 6awg ground pass through the box without a junction, but I have 12awg circuit that junctions in that box via other conduits, do I have to break the 6awg and bond that to the box and pig tail off of that?

Thanks
Jamie

chris75 02-18-2009 09:24 PM

I would not even pull a ground wire in EMT. :) great answer huh?

jamiedolan 02-18-2009 09:28 PM

Quote:

Originally Posted by chris75 (Post 232609)
I would not even pull a ground wire in EMT. :) great answer huh?

That would make it alot easier.

Do you think it is safe to use EMT as your fault path even for a sub panel or a hot tub if your EMT is put together securely?

Jamie

InPhase277 02-18-2009 09:29 PM

1 Attachment(s)
I'd just pull a #10 ground and bond with that, but since you didn't, you could use one of these:

chris75 02-18-2009 09:31 PM

Quote:

Originally Posted by jamiedolan (Post 232613)
That would make it alot easier.

Do you think it is safe to use EMT as your fault path even for a sub panel or a hot tub if your EMT is put together securely?

Jamie


Hot tubs fall under Article 680, with that said, The emt will actually end up clearing the fault regardless if you install a grounding conductor or not.

jamiedolan 02-18-2009 09:38 PM

Quote:

Originally Posted by chris75 (Post 232617)
Hot tubs fall under Article 680, with that said, The emt will actually end up clearing the fault regardless if you install a grounding conductor or not.

That's right, I just looked at 680 again, they require the insulated grounding conductor.

There is no requirement like that that applies to sub panels or equipment other than tubs/pools is there?

Thanks
Jamie

chris75 02-18-2009 09:42 PM

Quote:

Originally Posted by jamiedolan (Post 232625)
That's right, I just looked at 680 again, they require the insulated grounding conductor.

Yes.

Quote:

Originally Posted by jamiedolan (Post 232625)
There is no requirement like that that applies to sub panels or equipment other than tubs/pools is there?

Thanks
Jamie

No.

jamiedolan 02-18-2009 09:47 PM

Quote:

Originally Posted by InPhase277 (Post 232614)
I'd just pull a #10 ground and bond with that, but since you didn't, you could use one of these:


Thats good to know how to do that. I ran into the situation with a 12awg feed with a 10awg ground, and I just pigtailed and spliced the ground like I normally would.

When I pull the wire (this week) for my kitchen sub, I was going to pull a 6awg ground, but I can just use a 10 and make it easy (or use the emt as the fault path). It is going to run through a junction box as described with other wires that junction in it, that's really why I asked this question because I wasn't sure what to do in that box.

Thanks

Jamie

InPhase277 02-18-2009 10:42 PM

Quote:

Originally Posted by jamiedolan (Post 232633)
Thats good to know how to do that. I ran into the situation with a 12awg feed with a 10awg ground, and I just pigtailed and spliced the ground like I normally would.

When I pull the wire (this week) for my kitchen sub, I was going to pull a 6awg ground, but I can just use a 10 and make it easy (or use the emt as the fault path). It is going to run through a junction box as described with other wires that junction in it, that's really why I asked this question because I wasn't sure what to do in that box.

Thanks

Jamie

It would be a shame that you do all that over-the-top electrical work in the place just to go and bastardize it by using the EMT as your ground.

jamiedolan 02-18-2009 10:54 PM

Quote:

Originally Posted by InPhase277 (Post 232656)
It would be a shame that you do all that over-the-top electrical work in the place just to go and bastardize it by using the EMT as your ground.


Using the 10awg for my sub panel ground (vs using 6awg ground)would still be a first class setup, correct?
Basically no advantage in oversizing the ground wire, just as long as the ground wire is there and sized to what the NEC requires?
Thanks
Jamie

Stubbie 02-19-2009 12:05 AM

In conduit the ground is sized to the largest amperage circuit. If that is #10 then the ground back to the panel must be #10 but there is no reason for instance if you branch off at a device or jb to a 20 amp circuit device to use #10 you can use #12 spliced to the #10.

If all have is 20 amp circuits then #12 ground is fine anything else serves no purpose at all. Using emt as ground is good only if it is made up correctly and it is a complete emt system....not part emt and part non-metallic cable like nm-b. Your causing yourself a lot of grief using #6 and #10 if it isn't needed.. that frankly is insane overkill..:) #6 copper is ground for 200 amp circuit breaker!!! Your wasting good feeder ground and electrode grounding conductor are you really from this planet.....??

jamiedolan 02-19-2009 12:40 AM

Quote:

Originally Posted by Stubbie (Post 232677)
In conduit the ground is sized to the largest amperage circuit. If that is #10 then the ground back to the panel must be #10 but there is no reason for instance if you branch off at a device or jb to a 20 amp circuit device to use #10 you can use #12 spliced to the #10.

If all have is 20 amp circuits then #12 ground is fine anything else serves no purpose at all. Using emt as ground is good only if it is made up correctly and it is a complete emt system....not part emt and part non-metallic cable like nm-b. Your causing yourself a lot of grief using #6 and #10 if it isn't needed.. that frankly is insane overkill..:) #6 copper is ground for 200 amp circuit breaker!!! Your wasting good feeder ground and electrode grounding conductor are you really from this planet.....??


I was only using 6awg for 60a feed to a sub panel, but it sounds like 10 is fine for this.

I used the 10 ground for a4 wire 10 gage 30a feed to a sub

I thought you needed 4 for 200a service bond / grounding but never more than 6 for ground rods.

My emt systems are complete. I am trying to move away from romex and use all condiut systems, though some spots I do have to transition to smurf and use a ecg in the smurf.

Thanks
Jamie

jamiedolan 02-19-2009 12:46 AM

Quote:

Originally Posted by Stubbie (Post 232677)
In conduit the ground is sized to the largest amperage circuit. If that is #10 then the ground back to the panel must be #10

This is exactly what I have been doing:
20a 12awg get a 12awg ground
30a 10awg gets a 10awg ground
60a 6awg gets a 6awg ground

But now I understand for the 6awg I can use a 10awg ground wire.
Jamie

Stubbie 02-19-2009 01:26 AM

Jamie

Don't take me too seriously just poling some fun. Your doing fine.


2/0 200 amp service entrance conductor requires a grounding electrode conductor to the water pipe of #4 copper. NEC table 250.66

Your not sizing grounding electrode conductor....your sizing...equipment grounding conductor which is sized to the protecting circuit breaker. A #6 copper will suffice for a 200 amp breaker protecting a feeder. Use this table below...NEC table 250.122

http://www.ecmweb.com/mag/706ecmCBtable1.jpg

Or go here and use the calculators


http://www.electrician2.com/calculators/elcal.html

AllanJ 02-19-2009 07:41 AM

Out of curiosity, why would the grounding conductor need to be insulated?


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