Bonding 320 Amp meter enclosure

M

Moonchava

New User
Location
Carlsbad, NM
Occupation
Contractor
Want to hear some feedback on bonding 400 amp split panel services for residential applications. The local inspectors are always changing their minds on what they want done and wanna hear someone else’s input. In one occasion they wanted the electrode conductor entering the meter can and bonding to the neutral here. Then isolating the grounds in the first panel and passing equipment ground with the 200amp feeder. Now they are wanting bonding in the meter can and the first panel but not installing equipment ground between meter can and first panel. On a separate instance the same inspector wanted the electrode conductor entering the first 200 amp panels and isolating ground and neutral at the meter can. Which way is the correct way?
 
Locally, all the 320 amp meter cans are factory bonded to the neutral and the neutral to equipment bonding is performed at the service panel(s).
Per NEC the grounding electrode conductors are allowed to be connected at any point from the service point to the service entrance equipment.
That said, some of our utilities do not allow a GEC at the meter and some actually require a ground rod be connected at the meter.
 
Wit 400/320 services with two disconnects, I run the grounding electrode to the bonding block and then from there to each disconnect.
 
Moonchava said:
Want to hear some feedback on bonding 400 amp split panel services for residential applications. The local inspectors are always changing their minds on what they want done and wanna hear someone else’s input. In one occasion they wanted the electrode conductor entering the meter can and bonding to the neutral here. Then isolating the grounds in the first panel and passing equipment ground with the 200amp feeder. Now they are wanting bonding in the meter can and the first panel but not installing equipment ground between meter can and first panel. On a separate instance the same inspector wanted the electrode conductor entering the first 200 amp panels and isolating ground and neutral at the meter can. Which way is the correct way?
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These inspectors sound very confused. If the GEC(s) do not terminate upstream of the two service disconnects (panels) then they need to terminate within each panel. There are no EGC's ahead of the panels. If terminating within the panels the "tap method" is the easiest way to do it. The GEC is sized based on the service entrance conductors and a "tap" is made to each panel with a split bolt. The IBT cannot be used for the taps.
 
infinity said:
These inspectors sound very confused. If the GEC(s) do not terminate upstream of the two service disconnects (panels) then they need to terminate within each panel. There are no EGC's ahead of the panels. If terminating within the panels the "tap method" is the easiest way to do it. The GEC is sized based on the service entrance conductors and a "tap" is made to each panel with a split bolt. The IBT cannot be used for the taps.
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Why can't the IBT be used for taps?
 
infinity said:
If a bus bar is used for the interconnection of GECs and bonding jumpers it needs to comply with 250.64(F)(3). Also by Article 100 definition the IBT is only for communication systems.
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Dang. I've done it that way for years and no inspector has ever said anything. I'm not sure that 250.64(F)(3) was violated though. I don't have one of those blocks handy to look at, but I think they meet the 1/4"x2" requirement.
 
infinity said:
If a bus bar is used for the interconnection of GECs and bonding jumpers it needs to comply with 250.64(F)(3). Also by Article 100 definition the IBT is only for communication systems.
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Which are trending more to not existing anymore.

Past several new construction jobs I have done had nothing to connect to the IBT, they bring fiber in or even used wireless and had nothing to bond.
 
kwired said:
Which are trending more to not existing anymore.

Past several new construction jobs I have done had nothing to connect to the IBT, they bring fiber in or even used wireless and had nothing to bond.
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Around here the FiOS fiber ONT still gets bonded to the IBT.
 
infinity said:
Around here the FiOS fiber ONT still gets bonded to the IBT.
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I have not been seeing that. If anything a wireless dish/antenna probably should be bonded but many those are not either. Particularly the ones that just have POE cable ran to them. Anything with coax usually gets bonded, but those installers never run anything to your IBT. They will put a clamping device right on meter socket, panelboard, etc. even though the IBT is right nearby.

I can't recall anything ever landing on an IBT that I installed unless I was the one that landed it which only happens on service upgrades where I was the one that removed their bonding conductor from what was taken out and landed it on the IBT when all was said and done.

Good intention code wise but rather useless piece of hardware around here from what I have seen.
 
infinity said:
These inspectors sound very confused.
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I agree. While there are some different options for where to land the grounding electrode conductor, which might depend on local and utility rules about landing in the meter socket, the following are always TRUE:

1. Meter socket gets bonded to the neutral conductor (if it's on the supply side of the service disconnect, hot sequenced)
2. The service disconnect is also always bonded to the neutral , with neutrals and grounds common.
3. There is not an EGC between the meter and the service disconnect

Many people struggle with how to land the grounding electrical conductor on services with multiple service disconnects. I don't really understand why, it's laid out fairly clearly in the code book in 250.64. probably because a large percentage of inspectors and electricians haven't opened the code book since they got their license.
 
electrofelon said:
I agree. While there are some different options for where to land the grounding electrode conductor, which might depend on local and utility rules about landing in the meter socket, the following are always TRUE:

1. Meter socket gets bonded to the neutral conductor (if it's on the supply side of the service disconnect, hot sequenced)
2. The service disconnect is also always bonded to the neutral , with neutrals and grounds common.
3. There is not an EGC between the meter and the service disconnect

Many people struggle with how to land the grounding electrical conductor on services with multiple service disconnects. I don't really understand why, it's laid out fairly clearly in the code book in 250.64. probably because a large percentage of inspectors and electricians haven't opened the code book since they got their license.
Click to expand...
💯 it’s pretty sad 250.64 is clear there shouldn’t be confusion
 
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