Bonding at subpanel
- Thread starter JdoubleU
- Start date
- Status
- Location
- Logan, Utah
What bonding are you referring too?
Chris
Chris
construct
Senior Member
- Location
- Branson, Missouri
If you are talking Main Bonding Jumper 250.24(B) 2005 NEC, then no.
Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
Also take a look at 250.24(A)(1) & (A)(4)
I don't see anything in 250.94 or 250.104 prohibiting taking those bonds from a subpanel. There is no requirement that these bonding wires be unspliced. But the water bond has to be sized per 250.66, not 250.122. So if the subpanel EGC is that large, then I'd say you can bond those things from the subpanel. If the water pipe is a ground electrode, then that could be a problem, as a GEC can not be spliced.
If this is new construction, this doesn't alleviate the requirement for an intersystem bonding tie point.
If this is new construction, this doesn't alleviate the requirement for an intersystem bonding tie point.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
There is a requirement for the GEC to be unspliced --250.64(C), however it does allow you to use section of busbars to form a GEC.
I believe this is in reference to bonding all the gec's together thru the busbar. I believe 250.24(A)(1) states this connection must be made between the lateral or drop and including the service disconnect.
I believe this is in reference to bonding all the gec's together thru the busbar. I believe 250.24(A)(1) states this connection must be made between the lateral or drop and including the service disconnect.
From 250.94:The intersystem bonding termination shall be one of the following:
(1) A set of terminals securely mounted to the meter enclosure and electrically connected to the meter enclosure. The terminals shall be listed as grounding and bonding equipment.
(2) A bonding bar near the service equipment enclosure, meter enclosure, or raceway for service conductors. The bonding bar shall be connected with a minimum 6 AWG copper conductor to an equipment grounding conductor(s) in the service equipment enclosure, meter enclosure, or exposed nonflexible metallic raceway.
(3) A bonding bar near the grounding electrode conductor. The bonding bar shall be connected to the grounding electrode conductor with a minimum 6 AWG copper conductor.
From 250.104:
(1) General. Metal water piping system(s) installed in or attached to a building or structure shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with Table 250.66 except as permitted in 250.104(A)(2) and (A)(3).
shuntripper
Member
- Location
- Northern California
studying the Code isn't actually training for the trade. If you understand why the neutral disconnecting means at the service exists and the purpose of bonding the ground to neutral at the service, the proper course should be obvious. It's what makes a Journeyman a Journeyman, an Apprentice may know WHAT, the Journeyman knows WHY.
was that rude?
- Location
- Logan, Utah
Kind of, for a first post.
Welcome to the forum.
Chris
- Location
- Logan, Utah
I agree, I don't see a remote panelboard equipment grounding bus/bar listed in those sections.
Chris
OK, I'll give you the intersystem bonding tie point. It appears that you must use it for other systems, and you have to install one at or near the service if you don't have one.
But for a water pipe, an EGC to a subpanel does eventually go to the Service Equipment Enclosure. There is a splice on the way in the subpanel, but it does reach the service. To me, this is the same as pool feeders -- the EGC must be insulated all the way to the service, but I don't believe you're prohibited from having multiple panels on the way, you just have to have a compliant EGC the whole way to the service. For a pool, that means insulated. For a water bond, it means sized per 250.66.
shuntripper said:
I guess it isn't obvious to me. If we're talking just bonding the pipes, and not an electrode, why does it matter whether the pipe bond go direct to the service bonding point or get there via some other equipment ground? What is the difference between bonding a pipe and bonding an equipment enclosure?
electricmanscott
Senior Member
- Location
- Boston, MA
It is rude and I don't get it. :-?
erickench
Senior Member
- Location
- Brooklyn, NY
Do you by any chance mean a pool water bond? NEC 680.26 requires that a 9 sq-in conductive surface area must be in contact with the pool water and bonded. It also requires metal wiring and equipment to be bonded if within 5 feet horizontally and 12 feet vertically of the pool. If this subpanel is within those distances then it has to be bonded together with all the other equipment in the area including the water bond.
''
250.104 does not mention "eventually". It states where it shall be connected.
1) General. Metal water piping system(s) installed in or attached to a building or structure shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used.
crossman gary
Senior Member
First, 250.94 is not talking about the bonding of waterpipes, building steel, other piping systems, lightning protection systems, or anything like that.
Look up the definition in Article 100 and it will be evident that the intersystem bonding termination and 250.94 is talking about providing a grounding means for communications systems such as telephone, cable tv, internet. 250.94 does not apply to question at hand.
On to the question:
If the building steel and/or the waterpipe is used as an electrode, then the grounding electrode conductor cannot go the subpanel and be spliced using the ground bar. As Dennis said, 250.64 does allow us to use busbars as the GEC as in 250.64(C)(2)... but again as he said, that is when the entire GEC is made from busbar.
The other reference to busbars that Dennis made is 250.64(F)(3). This is when we use a minimum size 1/4" x 2" (I assume the CMP means cross sectional area) bus bar where we attach all the GECs from the various electrodes, then run a main GEC to the service.
Other folks picked up on this too.
Now, although I do not like it, and would most likely never do it....
If the interior metal waterpipe and/or the building steel is not an electrode, then it appears to me that there is nothing to prohibit a properly sized bonding jumper to go to a subpanel and then be ran back with the feeder to the service. Nothing in 250.94 makes me think that you can't.
Now, if that thought makes me "not a jw because I "have the understanding of an apprentice" then I suppose my head is spinning around on my neck right now. Although I understand electrical theory at least at a jw level, I am not in a position to read the minds of CMP #5 and make assumptions as to what their intent was. I must assume that CMP #5 is a literate body and is capable of expressing its intentions in an unambiguous manner!
Was that rude?
:grin:
Look up the definition in Article 100 and it will be evident that the intersystem bonding termination and 250.94 is talking about providing a grounding means for communications systems such as telephone, cable tv, internet. 250.94 does not apply to question at hand.
On to the question:
If the building steel and/or the waterpipe is used as an electrode, then the grounding electrode conductor cannot go the subpanel and be spliced using the ground bar. As Dennis said, 250.64 does allow us to use busbars as the GEC as in 250.64(C)(2)... but again as he said, that is when the entire GEC is made from busbar.
The other reference to busbars that Dennis made is 250.64(F)(3). This is when we use a minimum size 1/4" x 2" (I assume the CMP means cross sectional area) bus bar where we attach all the GECs from the various electrodes, then run a main GEC to the service.
Other folks picked up on this too.
Now, although I do not like it, and would most likely never do it....
If the interior metal waterpipe and/or the building steel is not an electrode, then it appears to me that there is nothing to prohibit a properly sized bonding jumper to go to a subpanel and then be ran back with the feeder to the service. Nothing in 250.94 makes me think that you can't.
Now, if that thought makes me "not a jw because I "have the understanding of an apprentice" then I suppose my head is spinning around on my neck right now. Although I understand electrical theory at least at a jw level, I am not in a position to read the minds of CMP #5 and make assumptions as to what their intent was. I must assume that CMP #5 is a literate body and is capable of expressing its intentions in an unambiguous manner!
Was that rude?
:grin:
crossman gary
Senior Member
Augie... I completely understand your viewpoint and I want to read it that way too. I'm just saying that if you pulled out a bunch of lawyers or perhaps had someone testify to Congress, then the section could be interpreted in another way.
I like your way.
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