What section of the NEC addresses how to determine the size of the bonding jumper required for a water heater? A local inspector is saying that the jumper must be sized to match the size of the building service, which in our case would require a 3/0 jumper. This seems to be overkill. Please advise.
Water heater grounding jumper
- Thread starter mglennon
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ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Water heater grounding jumper
250.104(A)
250.104(A)
jxofaltrds
Retired ESI
- Location
- Mike P. Columbus Ohio
- Occupation
- Creator
Re: Water heater grounding jumper
Use 1993 NEC as a start.
250.80(a) takes you to 250.94.
Do not have the 2002 in front of me but I thing a bonding jumper is not required to be over a 6awg???
Mike P.
Use 1993 NEC as a start.
250.80(a) takes you to 250.94.
Do not have the 2002 in front of me but I thing a bonding jumper is not required to be over a 6awg???
Mike P.
jxofaltrds
Retired ESI
- Location
- Mike P. Columbus Ohio
- Occupation
- Creator
Re: Water heater grounding jumper
What does 250.66(A) mean?
Mike P.
What does 250.66(A) mean?
Mike P.
jxofaltrds
Retired ESI
- Location
- Mike P. Columbus Ohio
- Occupation
- Creator
Re: Water heater grounding jumper
I am using 250.53(E). If that (the supplemental) is not required to be larger than 6awg copper then why should a cold to hot water line bond be required to be larger than 6awg copper?
Am I missing something or losing my mind?
Mike P.
I am using 250.53(E). If that (the supplemental) is not required to be larger than 6awg copper then why should a cold to hot water line bond be required to be larger than 6awg copper?
Am I missing something or losing my mind?
Mike P.
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Water heater grounding jumper
Mike, yes you are losing your mind.
We are not discussing a suplemental electrode. We are not talking about an electrode at all. We are talking about a piece of pipe.
Mike, yes you are losing your mind.
We are not discussing a suplemental electrode. We are not talking about an electrode at all. We are talking about a piece of pipe.
- Location
- Massachusetts
Re: Water heater grounding jumper
Mike we do not have to run larger than 6 awg to a rod electrode.
Bonding the water pipes to the service is entirely different.
As Ryan said you must go to 250.104(A)(1)
Mike we do not have to run larger than 6 awg to a rod electrode.
Bonding the water pipes to the service is entirely different.
As Ryan said you must go to 250.104(A)(1)
jxofaltrds
Retired ESI
- Location
- Mike P. Columbus Ohio
- Occupation
- Creator
Re: Water heater grounding jumper
Please work with me.
Why would a bonding jumper, cold to hot water, be required to be larger than 6awg copper?
I know 250.140(B) does not apply here, but what is the dif?
Mike P.
Please work with me.
Why would a bonding jumper, cold to hot water, be required to be larger than 6awg copper?
I know 250.140(B) does not apply here, but what is the dif?
Mike P.
- Location
- Massachusetts
Re: Water heater grounding jumper
Mike I do not know.
It appears that they want the all the water pipe to be bonded well enough to trip the main breaker for the service.
I am not sure how this would happen.
If you look at 250.104(B) for other metal piping you only need to size the bonding jumper to the overcurrent device likely to energize it.
Mike I do not know.
It appears that they want the all the water pipe to be bonded well enough to trip the main breaker for the service.
I am not sure how this would happen.
If you look at 250.104(B) for other metal piping you only need to size the bonding jumper to the overcurrent device likely to energize it.
jxofaltrds
Retired ESI
- Location
- Mike P. Columbus Ohio
- Occupation
- Creator
Re: Water heater grounding jumper
Bob
Thanx. That is my point. How could the "service" energize the metal pipes?
Dedicated space?
Mike P.
Bob
Thanx. That is my point. How could the "service" energize the metal pipes?
Dedicated space?
Mike P.
Re: Water heater grounding jumper
The largest circuit likely to energize a water pipe, is the water heater. Circuits running over under and beside the pipe, are not likely to energize the pipe.
The largest circuit likely to energize the gas pipe is a 20 amp circuit to a furnace.
#10 and #12 cu respectfully, will cause the breakers to trip in the event of a fault.
The largest circuit likely to energize a water pipe, is the water heater. Circuits running over under and beside the pipe, are not likely to energize the pipe.
The largest circuit likely to energize the gas pipe is a 20 amp circuit to a furnace.
#10 and #12 cu respectfully, will cause the breakers to trip in the event of a fault.
jxofaltrds
Retired ESI
- Location
- Mike P. Columbus Ohio
- Occupation
- Creator
Re: Water heater grounding jumper
So back to the original post---what is the answer?
AHJ says 3/0.
I say 6awg.
Bennie says (#12 or #10).
The bonding conductor in question is across the hot water tank.
Would this AHJ require a 3/0 to a cable tv, phone or satelite system?
Mike P.
So back to the original post---what is the answer?
AHJ says 3/0.
I say 6awg.
Bennie says (#12 or #10).
The bonding conductor in question is across the hot water tank.
Would this AHJ require a 3/0 to a cable tv, phone or satelite system?
Mike P.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Water heater grounding jumper
This is a very good example of getting two different code requirements crossed up. the requirement of a electrode with the requirement of a bond to the water pipe, gas pipe or what ever else they seem to think will be energized by the service. yes the water pipe could be energized by a electric water heater or a refrigerator and even the humidifier on the furnace but do you ever think that they will all short out at one time? I don't. this is why the code say to size the wire to the largest circuit likely to energize it. With a 30 amp electric water heater it would be a #10 that is ran with the circuit conductors. you might have to bond around any plastic connections on the water heater to make sure the bond is not broken.
[ December 23, 2003, 07:43 PM: Message edited by: hurk27 ]
This is a very good example of getting two different code requirements crossed up. the requirement of a electrode with the requirement of a bond to the water pipe, gas pipe or what ever else they seem to think will be energized by the service. yes the water pipe could be energized by a electric water heater or a refrigerator and even the humidifier on the furnace but do you ever think that they will all short out at one time? I don't. this is why the code say to size the wire to the largest circuit likely to energize it. With a 30 amp electric water heater it would be a #10 that is ran with the circuit conductors. you might have to bond around any plastic connections on the water heater to make sure the bond is not broken.
[ December 23, 2003, 07:43 PM: Message edited by: hurk27 ]
- Location
- Massachusetts
Re: Water heater grounding jumper
What part of 250.104(A) says anything about the largest circuit likely to energize it?
[ December 23, 2003, 07:50 PM: Message edited by: iwire ]
What part of 250.104(A) says anything about the largest circuit likely to energize it?
[ December 23, 2003, 07:50 PM: Message edited by: iwire ]
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Water heater grounding jumper
H'mmm
Iwire I'm mixed up now as 250.104 (B) says the other way:
(B) Other Metal Piping. Where installed in or attached to a building or structure, metal piping system(s), including gas piping, that may become energized 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 250.122 using the rating of the circuit that may energize the piping system(s). The equipment grounding conductor for the circuit that may energize the piping shall be permitted to serve as the bonding means. The points of attachment of the bonding jumper(s) shall be accessible.
FPN: Bonding all piping and metal air ducts within the premises will provide additional safety.
So this would only apply to a gas pipe Etc...
H'mmm
Iwire I'm mixed up now as 250.104 (B) says the other way:
(B) Other Metal Piping. Where installed in or attached to a building or structure, metal piping system(s), including gas piping, that may become energized 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 250.122 using the rating of the circuit that may energize the piping system(s). The equipment grounding conductor for the circuit that may energize the piping shall be permitted to serve as the bonding means. The points of attachment of the bonding jumper(s) shall be accessible.
FPN: Bonding all piping and metal air ducts within the premises will provide additional safety.
So this would only apply to a gas pipe Etc...
- Location
- Massachusetts
Re: Water heater grounding jumper
Yeah thats what Mike and I are taking about, why the difference for water pipes and "other metal piping"
The original post in this thread asked about an inspector wanting a 3/0 jumper at the water heater.
Why does this water piping past the water heater need a bonding jumper this large?
Yeah thats what Mike and I are taking about, why the difference for water pipes and "other metal piping"
The original post in this thread asked about an inspector wanting a 3/0 jumper at the water heater.
Why does this water piping past the water heater need a bonding jumper this large?
- Location
- Massachusetts
Re: Water heater grounding jumper
That is logical but it does not match the code.
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: Water heater grounding jumper
3/0
3/0
Re: Water heater grounding jumper
When the water pipe is an electrode, the Table for grounding electrode conductor 250.66 applies.
When bonding the pipe for fault clearing purposes only, the Table 250.122 applies.
#10 and #12 will work fine.
Wouldn't it be nice if the code book was worded like the above?
[ December 23, 2003, 10:43 PM: Message edited by: bennie ]
When the water pipe is an electrode, the Table for grounding electrode conductor 250.66 applies.
When bonding the pipe for fault clearing purposes only, the Table 250.122 applies.
#10 and #12 will work fine.
Wouldn't it be nice if the code book was worded like the above?
[ December 23, 2003, 10:43 PM: Message edited by: bennie ]
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