one meterbase serving resi and 2 shops

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Have a customer ( retired utility guy) who has 1 small shop in his back yard and is building a larger one in back. His 200a panel is pretty full so he wants to add a new panel outside his garage. I told him we would have to install a new meterbase 320A. The meterbase (double load side lugs) would feed the home then feed a small outdoor 125 amp panel with a 25 amp cb for the small shop and a 100A cb for the larger shop. I consider the new panel a separate system and this is the the disconnect for the shops. I told him we would bond the neutral in the new panel to ground, run a # 6 ground to his existing ground rod, and run grounds from the new panel to both buildings. At both shops we would NOT bond the neutral to ground. He disagrees with me and has has bonded both shops neutral bars. He insists he is correct. I disagree.
Any feed back appreciated.:roll::roll:
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
As of the 2008 NEC it is required to run 4 wires, 2 hots, a neutral and a ground to the separate structures. The grounds and neutrals must be separate or you would have a parallel neutral. The ground rods would connect to the EGC at the separate buildings. Of course at the main building where the 320 amp base is mounted, you would bond the neutral to the rods, etc
 

e57

Senior Member
At both shops we would NOT bond the neutral to ground. He disagrees with me and has has bonded both shops neutral bars. He insists he is correct. I disagree.
Any feed back appreciated.:roll::roll:
Which code cycle are you actually under - the '05 and before would accept this - the '08 does not. See 250.32 in which ever code cycle you're in.

BFWIW - I'm not sure from your description - but as described with a neutral bond and electrode system at each structure was acceptable for many years - so long as it did not have another metallic path between structures - like a water line...
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
Are you saying he as altered your install ? Your the contractor not him. If he thinks he knows more than you then collect what your owed and call in an inspector so this does not end up your problem. If not finished yet cancel the permit.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
Well then if no inspections or permits i would only direct him to nec. He does need ground rods and neutral and grounds not bonded at them. As a utility man he is really not qualified but its not your problem. Do your part to code and walk away. Be dam sure to indicate this on your bill for legal protection. Seems strange that he thinks he can do all but the main service.
 

kwired

Electron manager
Location
NE Nebraska
What is your total load calculation? Unless electric heating is involved 200 amp service possibly may be able to handle all of it.

I consider the new panel a separate system and this is the the disconnect for the shops.
This breaker is permited but is not the disconnect required by 225.32.

As others have mentioned if you are under 2008 code you must have separate grounded (neutral) and equipment ground to separate structures supplied by another structure.

If you would go from the meter directly to the separate building you still have service equipment at separate building and would not be required to run separate equipment ground but must bond the neutral at the main in the second building.

If you are putting the new panel you mentioned on the outside of the garage and leave existing service in the house as it is you may have a violation of 230.2 because you can only have one service supplying a building or structure. Your second service does not supply the building it is on but you do have a second service there.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
why are rods req at each bldg. if we ran the grounds from the new panel?
out in the country no inspections
The rods are not used for the same purpose as the EGC. Rods are basically for lightning protection. Out in the country, no inspection, etc does not exonerate you from doing it to code.
 

kwired

Electron manager
Location
NE Nebraska
Have a customer ( retired utility guy)... ..... and has has bonded both shops neutral bars. He insists he is correct. I disagree.
Any feed back appreciated.:roll::roll:
This would be normal thinking for a utility person, they bond everything to grounded conductor and have no idea what a grounding conductor is for the most part.

They don't use equipment grounding conductor because they never are required to. Everything they do is service side of equipment and everything is bonded to neutral conductor.
 
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The customer wanted a new panel outside his garage with breakers to both bldgs. The new 320a meter base feeds the new panel and the new panel feeds both separate shops. meterbase also feeds the home. 320a meter base with lugs on the load side to feed the home and the new panel outside the garage. He then added a panel at each bldg.
 

e57

Senior Member
This would be normal thinking for a utility person, they bond everything to grounded conductor and have no idea what a grounding conductor is for the most part.

They don't use equipment grounding conductor because they never are required to. Everything they do is service side of equipment and everything is bonded to neutral conductor.
And for many many many years the code allowed it like the client wants it (as far as the bonding of neutral) - but no longer. But an electrode was always required - and still are as far as I know... It does not need to be rods... A Ufer, plate, or water - but water would require additional rods... and since I doubt anyone is testing rod resistance - two rods... But two rods would surfice....

FWIW it was my prefered method for a long time.... ;)
 

e57

Senior Member
The customer wanted a new panel outside his garage with breakers to both bldgs. The new 320a meter base feeds the new panel and the new panel feeds both separate shops. meterbase also feeds the home. 320a meter base with lugs on the load side to feed the home and the new panel outside the garage. He then added a panel at each bldg.
Should mention - a disconnecting means is also required at each building - but a main CB panel at each could solve that...
 

kwired

Electron manager
Location
NE Nebraska
And for many many many years the code allowed it like the client wants it (as far as the bonding of neutral) - but no longer. But an electrode was always required - and still are as far as I know... It does not need to be rods... A Ufer, plate, or water - but water would require additional rods... and since I doubt anyone is testing rod resistance - two rods... But two rods would surfice....

FWIW it was my prefered method for a long time.... ;)
Was my preferred method also, but many utility guys still don't understand concept of grounded and grounding conductors. They would still think bonding of neutral to exposed metal on branch circuits is acceptable because this is how they do their work all the time.
 
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