# 400 amp residential service water line bonding



## Dennis Alwon (May 9, 2009)

Look at Table 250.66 Note 1 Actual #2 would have been fine


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## Dennis Alwon (May 9, 2009)

cir mil 3/0 = 167800

167800 * 2 = 335600 next standard size wire is 350,000 which is 350Kcm. Table 250.66 allows #2 grounding electrode conductor.

Now if you had run just a single set such as 500 kcm (380 amps) at 75C then you would have needed the 1/0.


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## Anathera (Feb 16, 2016)

alright, still exceptionally larger than the #6 that i was told to run. I ended up running the 1/0 anyways. Thanks for the help


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## joebanana (Dec 21, 2010)

Just out of curiosity, how many sq.ft./bdrms? Sounds like a small motel, for a 400a.service.


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## Dennis Alwon (May 9, 2009)

joebanana said:


> Just out of curiosity, how many sq.ft./bdrms? Sounds like a small motel, for a 400a.service.


We do 400 amps all the time because many of the homes are all electric. Then add in a pool, hot tub etc and it is best to have a 400 amp service. We did a few homes with 600 amp services but never hit the 800 amp mark yet.


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## Dennis Alwon (May 9, 2009)

BTW, the gas lines do not need to bonded with #2 or 1/0. If there is a gas furnace then the equipment grounding conductor for that circuit is enough to bond the gas lines.. 250.104(B)



> (B) Other Metal Piping. If installed in, or attached to, a
> building or structure, a metal piping system(s), including
> gas piping, that is likely to become energized shall be
> bonded to any of the following:
> ...


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## joebanana (Dec 21, 2010)

Dennis Alwon said:


> We do 400 amps all the time because many of the homes are all electric. Then add in a pool, hot tub etc and it is best to have a 400 amp service. We did a few homes with 600 amp services but never hit the 800 amp mark yet.


Here in So. Cal. everything is gas, we never do 400a. resi.(that I'm aware of) Even with a spa, pool, central air, etc. Did one resi. with an elevator once, still only had a 200a. I guess anything is possible though.


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## donaldelectrician (Sep 30, 2010)

Dennis Alwon said:


> We do 400 amps all the time because many of the homes are all electric. Then add in a pool, hot tub etc and it is best to have a 400 amp service. We did a few homes with 600 amp services but never hit the 800 amp mark yet.




Those are the 320 continuos ones ( 400 A /320 A) meter base ...


Right Dennis ?


Not the Commercial 400 A Continuos .



Don


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## Dennis Alwon (May 9, 2009)

donaldelectrician said:


> Those are the 320 continuos ones ( 400 A /320 A) meter base ...
> 
> 
> Right Dennis ?
> ...



That is correct but it is still a 400 amp service


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## Anathera (Feb 16, 2016)

It's a four bedroom house approximately 6000 Sq feet but it is part of our campus we maintain and they like to keep adding things if you know what I mean. We put in the 400 because we don't want to get jammed up in the future


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## 3DDesign (Oct 25, 2014)

Our standard practice is anything over 4,000 sq. ft gets 400 amp and yes #2 ground.


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## Dennis Alwon (May 9, 2009)

3DDesign said:


> Our standard practice is anything over 4,000 sq. ft gets 400 amp and yes #2 ground.


The #2 grounding electrode conductor depends on the install. If you use a 400 amp meter main panel then you would have to use 1/0. I assumed you knew this but I wanted to clarify to others

250.66 Note 2



> 2. Where there are no service-entrance conductors, the grounding
> electrode conductor size shall be determined by the equivalent size of
> the largest service-entrance conductor required for the load to be
> served.


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## farmantenna (Nov 22, 2012)

even up here in Massachusetts large homes get 400 amps because of the large load for multiple AC condensers . I have seen homes with 4-5 AC conensers drawing 30-40 amps each.


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## frenchelectrican (Mar 15, 2007)

The only resdentiial that hit 800 amp single phase which the poco was not too crazy with it.. But with that big a service ..
I end up put iin 3 ph service and it work out good.. It iis 600 A. 208Y120


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## Anathera (Feb 16, 2016)

This one had three ac units with electric heat and a mini split. We had over 120 amps in heating alone


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## mbednarik (Oct 10, 2011)

You would need to bond with #6 cu is csst was installed. Our state inspectors here make it part of our job to provide bonding to the gas manifold if csst is installed. I think it straight up calls for #6.


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## Anathera (Feb 16, 2016)

They ran black pipe the whole way our hvac guy hates the yellow stuff

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