Outside disconnect switch

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jeff43222

Senior Member
I'm doing another service upgrade tomorrow, and I was thinking about grounding the disco switch. I know the switch must be grounded to the water pipe and a supplemental rod, and bonded to the panelboard inside. Would it be OK to run the water ground from the inside panelboard ground bar rather than from the outside disco switch? Seems to me that since the panelboard ground is connected to the disco switch housing, it would be just as good to run the water ground from the inside panelboard.
 

iwire

Moderator
Staff member
Location
Massachusetts
Jeff the GEC must run to the point where the service is bonded or on the supply side of that.

In your case it must be somewhere between the outside service disconect and the 'service point'

250.24(A)(1)
 

jxofaltrds

Inspector Mike®
Location
Mike P. Columbus Ohio
Occupation
ESI, PI, RBO
Jeff

You could install a busbar inside and make the bonding there. If I understand your question.

250.64(C)(3)
Note the 2" is the width and not the length.
 

hillbilly

Senior Member
Jeff....iwire it right. The GEC (sized according to 250.66) must land in and be bonded to the Main service disconnect (or UPSTREAM at the meter). The Main Bonding Jumper will be installed in this disconnect. The Equipment Bonding Jumper (sized according to Table 250.122) between the Main (service overcurrent) Disconnect and the inside breaker panel can land in the breaker panel on the (bonded) grounding bar. The grounded (neutral) and grounding conductors must be isolated from each other (starting) at the Main Bonding Jumper.
steve
 

iwire

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Staff member
Location
Massachusetts
jxofaltrds said:
Jeff

You could install a busbar inside and make the bonding there. If I understand your question.

Not exactly.

You still have to provide the bonding at the service disconnect.

You could install a bus bar inside run bonding jumpers from each electrode to this bus bar but than a GEC from that busbar must run out to the service disconect or the supply side of that.
 

hillbilly

Senior Member
iwire said:
Not exactly.

You still have to provide the bonding at the service disconnect.

You could install a bus bar inside run bonding jumpers from each electrode to this bus bar but than a GEC from that busbar must run out to the service disconect or the supply side of that.

I-wire...If I'm understanding correctly?...If he runs the GEC from the bus bar in the panel, back to the main disconnect, it won't be continuous (as required by 250.64(C). 250.24 requires the GEC to connect at the point where the Grounded Service Conductor is connected (or before).

What am I missing?
steve
 

iwire

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Staff member
Location
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hillbilly said:
I-wire...If I'm understanding correctly?...If he runs the GEC from the bus bar in the panel, back to the main disconnect, it won't be continuous (as required by 250.64(C). 250.24 requires the GEC to connect at the point where the Grounded Service Conductor is connected (or before).

What am I missing?
steve

Morning Steve.

The bus bar inside I was talking about is not in a panel.

The NEC allows installing a bus bar out in the open to which you can connect all the grounding electrodes to.

The conductors from the bus bar to the grounding electrodes are not GECs they are bonding jumpers.

Now the conductor that connects this bus bar to the services grounded conductor is a GEC and must be continuous from the bus bar to the grounded conductor.

Personally I can not see the need of a bus bar in a dwelling unit but in commercial work it is becoming very common as there are often to many conductors to bring all of them into the service disconect
 

hillbilly

Senior Member
jxofaltrds said:
250.64(a-f).
Oh, you mean the section about Grounding Electrode Conductor Installation. The same one that I referenced in my reply to the OP? (just kidding). I'm a good reader, and I still can't understand how it allows what you guys are describing. I assume that you're using exception (3)? I've got my 2005 NEC in the house, my 2002 is in the truck. Is there any difference in the language?
steve
 

iwire

Moderator
Staff member
Location
Massachusetts
Steve which part are you having trouble with?

The GEC being continuous?

Right now I am under a bit of a disadvantage as I have misplaced my 2005 NEC.

However even under the 2002 only the GEC must be continuous, you may use bonding jumpers between electrodes.

Here is my often posted hand book graphic that shows what is a GEC and what is a bonding jumper.

Bonding_Jumpers.JPG
 

hillbilly

Senior Member
Oops......Just read it again. My bad. You guys are absolutely correct. I'm a good reader, I just didn't turn the page and read far enough.
steve
 

hillbilly

Senior Member
Yes, it was the part about it being continuous. I didn't see how travelling thru a terminal bar could construed as being continuous. 250.64(F) allows just this connection to the terminal bar (as you guys described). I've always thought that the GEC had to be continuous [without (reversible) splice, busbar termination, etc] from the grounding electrode to the Grounded Service conductor, no exception. I've always known that I can add Bonding Jumpers to as many additional electrodes as I wish, but thought that the GEC couldn't be spliced. Apparently I was wrong. Am I reading it right now?
This is a great web site.
thanks
steve
 

iwire

Moderator
Staff member
Location
Massachusetts
I believe that the bus bar deal went in for 2005 so it's not like you have been missing it for long.

It seems you got it now and yes it is a great site, I still learn things here all the time.

Learning never stops if your interested in the trade. :)
 
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