Is it a subpanel?

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Fred B

Senior Member
Location
Upstate, NY
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Electrician
This is an old install (about late 1960's early 70's) that is getting some major work done but no service changes yet, HO says that is on phase 2 of his renovation (doesn't make sense but). Meter/disconnect combo 200amp, about 200ft from house (and has a Kohler 50kw gen up by disconnect both added later not necessarily pertinent), bonding and ground rods is evident at meter disconnect. Main panel at house also has neutral/ground bonded. Is this a violation and creating parallel paths? Could this be one reason of seeing evidence of heating of the breakers and wires in the main panel as well as one of the subpanel run from this main panel? (Old Westinghouse main panel 200A and old Murray subpanel 100A) (There is also a newer SD 60A sub.) Did measurement of temperature on a couple of occasions during partial deservicing for renovations being done showed 20-25oF above ambient of nearby breakers on breakers showing heat degradation.

2nd question is on the subpanel that is there, beyond issue that most of all the grounds have been terminated under a single terminal lug bolted to the EGC no bus, I have several 240V circuits run with 10/2 NM that the bare ground conductor is terminated on the nuetral bus, (appears to be the water heater, sewage grinder pump, and an electric heater a couple of other yet to be identified) is this right or wrong?

Side note: All wiring the old NM, no NM-B (other than from newer SD sub). Did load calculations for house as every panel loaded except the SD 8 space that still had 3 slots. Calculations were done because HO wants to add a Tesla charger. I came up with it requiring 258 Amps based on sqft and some of the known loads. My recommendation has been do the upgrades now, money doesn't seem to be issue, seems more of timing, he wanted to be in for the holidays. But now his current "appearances upgrades" are going to take him out past that timeline anyway, and are opening walls, so going to push for the upgrades now rather than "phase 2". Is there, from my post, sufficient justification to push for the upgrades now rather than later other than convenience of walls being opened? And there does not seem to have sufficient capacity for the addition of the 50A Tesla charger. Any code reasons? (Please specify) Recommendations?
 

Greentagger

Senior Member
Location
Texas
Occupation
Master Electrician, Electrical Inspector
The service disconnecting means set remote from house has already been bonded as you stated. No more load side connections at house permitted. GES required at house. Don’t think ( or not sure) if that has anything to do with the heating problems you’re seeing? 4 wire feeders required at each sub panel. Separate grounded and grounding conductors at each.
 

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
The service disconnecting means set remote from house has already been bonded as you stated. No more load side connections at house permitted. GES required at house. Don’t think ( or not sure) if that has anything to do with the heating problems you’re seeing? 4 wire feeders required at each sub panel. Separate grounded and grounding conductors at each.
That's what I thought, just wasn't sure when it became code, or if maybe the initial installation was ever even "legal". If it was "legal at time of installation would the installation be "grandfathered"? That old Westinghouse doesn't have a seperate ground bus and I dont know of any parts available (ie new ground bus).
Wouldn't overloads if parallel paths are present require much higher fault to open a breaker, and would that create heating if fault not clearing, if indeed a partial fault is present as cause of heating?
 

Greentagger

Senior Member
Location
Texas
Occupation
Master Electrician, Electrical Inspector
Is this a 3 wire or 4 wire from remote disconnect to house? And yes, what was compliant (if indeed compliant) is still compliant.
 

ActionDave

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Durango, CO, 10 h 20 min from the winged horses.
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Licensed Electrician
..... Meter/disconnect combo 200amp, about 200ft from house bonding and ground rods is evident at meter disconnect. Main panel at house also has neutral/ground bonded. Is this a violation and creating parallel paths? Could this be one reason of seeing evidence of heating of the breakers and wires in the main panel as well as one of the subpanel run from this main panel?
Depending on the location of the Service Point according to the local utility this may be or have been allowed. I doubt it has anything to do with breakers getting warm. I have the same set up at my house. Pretty common on farms to have a meter serving several buildings, each with the neutral rebonded at the building disconnect. It is not a safety problem unless there is something like a water pipe, phone wire, or other conductive path between the meter disconnect and the main on the house.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
This is an old install (about late 1960's early 70's) that is getting some major work done but no service changes yet, HO says that is on phase 2 of his renovation (doesn't make sense but). Meter/disconnect combo 200amp, about 200ft from house (and has a Kohler 50kw gen up by disconnect both added later not necessarily pertinent), bonding and ground rods is evident at meter disconnect. Main panel at house also has neutral/ground bonded. Is this a violation and creating parallel paths?

See the exception to 250.32(B). This was allowed in the past and is allowed to remain if it meets the requirements.

You haven't mentioned anything that creates a parallel path. Doesn't mean there isn't one.

Could this be one reason of seeing evidence of heating of the breakers and wires in the main panel as well as one of the subpanel run from this main panel?

I don't see how. Probably a separate problem. If you had said heating of conduit or enclosures that might be due to parallel paths.

(Old Westinghouse main panel 200A and old Murray subpanel 100A) (There is also a newer SD 60A sub.) Did measurement of temperature on a couple of occasions during partial deservicing for renovations being done showed 20-25oF above ambient of nearby breakers on breakers showing heat degradation.

2nd question is on the subpanel that is there, beyond issue that most of all the grounds have been terminated under a single terminal lug bolted to the EGC no bus, I have several 240V circuits run with 10/2 NM that the bare ground conductor is terminated on the nuetral bus, (appears to be the water heater, sewage grinder pump, and an electric heater a couple of other yet to be identified) is this right or wrong?[/QUOTE]

Sounds wrong, if I'm understanding your description correctly that this is in a separate a sub off the main house panel.

Side note: All wiring the old NM, no NM-B (other than from newer SD sub). Did load calculations for house as every panel loaded except the SD 8 space that still had 3 slots. Calculations were done because HO wants to add a Tesla charger. I came up with it requiring 258 Amps based on sqft and some of the known loads. My recommendation has been do the upgrades now, money doesn't seem to be issue, seems more of timing, he wanted to be in for the holidays. But now his current "appearances upgrades" are going to take him out past that timeline anyway, and are opening walls, so going to push for the upgrades now rather than "phase 2". Is there, from my post, sufficient justification to push for the upgrades now rather than later other than convenience of walls being opened? And there does not seem to have sufficient capacity for the addition of the 50A Tesla charger. Any code reasons? (Please specify) Recommendations?

258A is huge for any residence in my experience. Did you look at the optional 220.82 or 220.83 calculations? Or get interval data and see what it needs per 220.84? Is it an all electric home?

If over 200 is still needed then in principle per the code I agree with your assessment not to install the car charger until the service is upgraded. But in reality...? I'd wager its fine as is, unless this is a palatial mansion. Especially if you change all the lighting to LED, then the code required sq ft multiplier is obsolete.
 

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
See the exception to 250.32(B). This was allowed in the past and is allowed to remain if it meets the requirements.

You haven't mentioned anything that creates a parallel path. Doesn't mean there isn't one.
Isn't neutral/ground bonded at both the meter disconnect and the main house panel a parallel path?

258A is huge for any residence in my experience. Did you look at the optional 220.82 or 220.83 calculations? Or get interval data and see what it needs per 220.84? Is it an all electric home?

If over 200 is still needed then in principle per the code I agree with your assessment not to install the car charger until the service is upgraded. But in reality...? I'd wager its fine as is, unless this is a palatial mansion. Especially if you change all the lighting to LED, then the code required sq ft multiplier is obsolete.
It's over 6100 sqft, they dont like LED, recalculated using Mike's app, getting 209 amp min load without the Tesla, 233A min with Tesla charger. They have 2 irrigation systems and a sewerage pump. A commercial electric range and commercial refrigerator. The app has no input for 2 large oil heaters with UV air filtration.
There is also an additional outbuilding 100A panel running off 30A breaker on meter/disconnect. Lighting, receptacles, and a panel that says Kohler battery charger DC inverter, not familiar with that device's load.
 

kwired

Electron manager
Location
NE Nebraska
re-grounding at the house would have been code compliant at the time of install. And still would be via exception if upgrading equipment but not the feeder conductors if there are no parallel metallic pathways present.

Some places may not consider that disconnect at the pole to be the service disconnect, as mentioned can depend on where the actual "service point" is located, and can be more complicated if 2020 NEC applies as you must have an outdoor emergency disconnect, but it doesn't necessarily need to be the service disconnect.

None of that has anything to do with overheating of ungrounded conductors or breaker terminals - those likely are simply failing connections where a little resistance turns into heating and over time the connection just gets worse. Put some heavier load on them, but not to "overloading levels" give them a little time to heat up and take temp reading with an infrared thermometer. If you have 240 volt load (same current both lines) and one pole is hot the other not, good sign right there of a failing connection.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Isn't neutral/ground bonded at both the meter disconnect and the main house panel a parallel path?

What Dave said. If the only metallic path connecting the two neutral bars is a neutral wire, there's no other path. You haven't mentioned if the wires are in metal conduit or anything else.

It's over 6100 sqft, they dont like LED, recalculated using Mike's app, getting 209 amp min load without the Tesla, 233A min with Tesla charger. They have 2 irrigation systems and a sewerage pump. A commercial electric range and commercial refrigerator. The app has no input for 2 large oil heaters with UV air filtration.
There is also an additional outbuilding 100A panel running off 30A breaker on meter/disconnect. Lighting, receptacles, and a panel that says Kohler battery charger DC inverter, not familiar with that device's load.

Ok, sounds like a 400A service upgrade is called for.
 

Dsg319

Senior Member
Location
West Virginia
Occupation
Wv Master “lectrician”
Depending on the location of the Service Point according to the local utility this may be or have been allowed. I doubt it has anything to do with breakers getting warm. I have the same set up at my house. Pretty common on farms to have a meter serving several buildings, each with the neutral rebonded at the building disconnect. It is not a safety problem unless there is something like a water pipe, phone wire, or other conductive path between the meter disconnect and the main on the house.
I might or might not understand this correctly. So for instance you have a meter main at a pole remote from the house. Than have “sub panel” at house and a detached garage. I’ve always thought to only have neutral/EGC bond at first means of disconnect.

So at the house and the garage “sub panels” would it be incorrect to have that neutral/EGC bond? I’ve always thought it was incorrect due to building steel and whatever else is possible bonded to EGC and causing objectional current.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
I might or might not understand this correctly. So for instance you have a meter main at a pole remote from the house. Than have “sub panel” at house and a detached garage. I’ve always thought to only have neutral/EGC bond at first means of disconnect.

So at the house and the garage “sub panels” would it be incorrect to have that neutral/EGC bond? I’ve always thought it was incorrect due to building steel and whatever else is possible bonded to EGC and causing objectional current.
1. If there are no parallel paths between any of the sub panels at any other separate structure you do not have a safety issue. Before 2005 NEC you would not have had a code issue because you were allowed to re bond the neutral at a separate structure.

2. Where I live a meter ped with a 200A breaker is installed at the property line by the utility. As far as my inspector is concerned that breaker belongs to the utility and is not the first means of disconnect.
 

Dsg319

Senior Member
Location
West Virginia
Occupation
Wv Master “lectrician”
1. If there are no parallel paths between any of the sub panels at any other separate structure you do not have a safety issue. Before 2005 NEC you would not have had a code issue because you were allowed to re bond the neutral at a separate structure.

2. Where I live a meter ped with a 200A breaker is installed at the property line by the utility. As far as my inspector is concerned that breaker belongs to the utility and is not the first means of disconnect.
Gotcha thanks for clearing it up! Also at separate structures where EGC and neutral bus are separated and you have additional grounding electrode system do you bond the grounding electrode conductor to the EGC bus correct?
 

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
No. A parallel path would be what I said, another metallic path connected to the house and the meter
But isn't that what I have with having a ground as well as the neutral running in between the 2 in the conduit at least as far as I can tell both continue thru. The ground wire goes unto the same conduit with the other wires at the house panel. Haven't checked the gen ATS panel, has a padlock and new owner doesn't have or cant find it. It must go to it, as the meter panel has what looks to be atleast 300kcmil conductors and house has 4/0.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
But isn't that what I have with having a ground as well as the neutral running in between the 2 in the conduit at least as far as I can tell both continue thru. The ground wire goes unto the same conduit with the other wires at the house panel. Haven't checked the gen ATS panel, has a padlock and new owner doesn't have or cant find it. It must go to it, as the meter panel has what looks to be atleast 300kcmil conductors and house has 4/0.
I didn't see anything about an additional metallic path between the meter and the house in your OP.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
But isn't that what I have with having a ground as well as the neutral running in between the 2 in the conduit at least as far as I can tell both continue thru. The ground wire goes unto the same conduit with the other wires at the house panel. Haven't checked the gen ATS panel, has a padlock and new owner doesn't have or cant find it. It must go to it, as the meter panel has what looks to be atleast 300kcmil conductors and house has 4/0.

That's the first time you've mentioned that there is both a ground and a neutral wire. If that's the case, then yes, separate them.

A lot of older installations don't have the ground.
 

kwired

Electron manager
Location
NE Nebraska
But isn't that what I have with having a ground as well as the neutral running in between the 2 in the conduit at least as far as I can tell both continue thru. The ground wire goes unto the same conduit with the other wires at the house panel. Haven't checked the gen ATS panel, has a padlock and new owner doesn't have or cant find it. It must go to it, as the meter panel has what looks to be atleast 300kcmil conductors and house has 4/0.
That's the first time you've mentioned that there is both a ground and a neutral wire. If that's the case, then yes, separate them.

A lot of older installations don't have the ground.
Yes, if there is separate N and EGC with a feeder never bond the N again beyond the service equipment. They are not "in parallel" if not bonded together at both ends. And remember a metallic raceway is a qualifying EGC and will carry neutral current if bonded to the neutral at the load end of the feeder.
 
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