Multiple GEC on one lug?

Status
Not open for further replies.
jjhoward

jjhoward

Senior Member
Location
Northern NJ
Occupation
Owner TJ Electric
Are multiple GECs on the same lug not allowed by the NEC? My AHJ failed me for the #4 Awg bare cu from the exterior rods and the #4 awg bare CU to the water pipe inside both landing on the same lug in of the ground bus in the 200 amp breaker panel. Is there an NEC article that covers this?
Thanks
 
Re: Multiple GEC on one lug?

Thanks Don,
Are there lugs/w screws that accept more than 1 conductor that are for panel bus bars?
 
Re: Multiple GEC on one lug?

Usually the neutral/equipment ground bar will take up to a # 4 so there should be no reason to double up the larger lug.
 
Re: Multiple GEC on one lug?

jj on a side note and only incase you didn't know it, you only need use a #6 bare copper to the ground rod. No need to use a #4 to the ground rod in any such case.

Just an FYI...
 
Re: Multiple GEC on one lug?

I don't do a lot of services but I use 4 for GEC and bonding jumpers because I have a spool of it. I bought it because I don't have to protect it if it's exposed.
 
Re: Multiple GEC on one lug?

Another thing you might find useful, since you use main breaker panels, is that you can terminate your ground rod (with #6, as mentioned above) to your water pipe within 5' of the entrance. It doesn't need to go to the panel.

I think. :D

Check out this thread: iWire's Grounding Lesson for Me
 
Re: Multiple GEC on one lug?

Ok, I am much clearer on this now. (I hope I can say this tomorrow!)
The referenced post by iWire was very good.
Re: the size of the EGC, #6 cu is the max I need to my main breaker panel. If I have a disconnect by the meter pan, I #6 cu is the max needed there. But the gnd from the disconnect to the service panel is dictated by table 250.66? Is that so??
 
Re: Multiple GEC on one lug?

Ok, I am much clearer on this now. (I hope I can say this tomorrow!)
Click to expand...
Boy Howdy! Ain't that the case. . .I really got a laugh out of that. Thanks, Joe :)
 
Re: Multiple GEC on one lug?

Yes, 250.64(B)

Edit: Hey, I just noticed you have the code reference already.

[ March 08, 2005, 11:57 AM: Message edited by: physis ]
 
Re: Multiple GEC on one lug?

If it's a question of how to interpret 250.64(B) it's a might vague. In my experience inspectors usually take it to mean you'll have to protect 6 ga. sometimes even when there is no threat of physical damage and 4 ga. only if there's an obvious risk of damage.

Edit: Typed the code no. wrong.

[ March 08, 2005, 12:08 PM: Message edited by: physis ]
 
Re: Multiple GEC on one lug?

Originally posted by jjhoward:
Re: the size of the EGC, #6 cu is the max I need to my main breaker panel. If I have a disconnect by the meter pan, I #6 cu is the max needed there. But the gnd from the disconnect to the service panel is dictated by table 250.66? Is that so??
Click to expand...
This is clearer if you state the function of each conductor.

GEC's are grounding electrode conductors. This conductor runs between the first means of disconnect for the building, and the grounding electrode. The size of your GEC is determined by table 250.66, as amended for specific electrodes in 250.53 (E - H). Your water pipe isn't amended by these sections, so it will be the full size determined by table 250.66.

EGC's are equipment grounding conductors, sized according to 250.122. These occur after the first means of disconnect for a building.

If there is a disconnect outside, feeding a panel or two on the inside, the size of those EGC's are determined by 250.122.

Before, or to, disconnect: 250.66
After Disconnect: 250.122

Hope this helps.
 
Re: Multiple GEC on one lug?

In essence you are only required to have one GEC. If there are other ELECTRODES available (soon to be "present" - '05), then you have 2 options.

1. Install the conductor(GEC) from the electrode back to the point of the first point of disconnect [250.64(F)... or to one or more grounding electrode(s) individually]. That conductor(s) will then be a GEC and has to remain unbroken and unspliced (250.64(C).

2. If using the cold water as your electrode, then it is to be SUPPLEMENTED[250.53(D)(2)].
This "supplemental" electrode is just that, supplemental, and can be bonded to a number of different locations as specified in
250.53(D)(2) The Supplemental electrode shall be permitted to be "BONDED" to the grounding electrode conductor, the grounded service conductor, the nonflexible grounded service raceway, or any grounded service enclosure.

There is an exception, but that exception is for industrial & commercial occupancies with supervised maintenance.

I do not see where this permits bonding to the cold water pipe (electrode) for any other occupancy.

The other electrodes that are available only need to be "bonded" together to form the Grounding Electrode System (250.50).
 
Status
Not open for further replies.
Top