Came across a residential 200 A Cutler-Hammer sub panel (there is 200 A service disc/outside of house after meter) that has 2 ground bus bars & 2 neutral bus bars. Trying to find NEC code that references size of conductors going from one ground bus bar to the other & from one neutral bus bar to the other. Currently panel has no jumper conductor between ground bars (only going through panel/enclosure via screws) & has # 2 cu jumper between neutral bus bars. Use 250.122 (#6 AWG jumper) between gnd bus bars & 310.12 @ 2/0 CU or 4/0 AL for neutral bus jumper?
Multiple ground & neutral bars
- Thread starter GregHouse
- Start date
- Status
- Location
- New Jersey
- Occupation
- Journeyman Electrician
The EGC bars do not require a jumper, the connection with the proper screws to the panel enclosure is all that is needed.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Size per 250.66
texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
I think you mean 250.102 unless you are talking a few code cycles back where you 250.66 as the basis.
No replies on the 310.12 @ 2/0 CU or 4/0 AL for neutral bus jumper?
Residential 200 A Cutler-Hammer sub panel (there is 200 A service disc/outside of house after meter) that has 2 ground bus bars & 2 neutral bus bars. Need to remove non insulated strap (bonded to panel) that goes from neutral bus to neutral bus (in sub panel) then jumper neutrals (not bonded) to avoid bonding in sub panel. I was looking for code reference for jumper size & thinking 310.12 @ 2/0 CU or 4/0 AL conductor as 200A service.
Residential 200 A Cutler-Hammer sub panel (there is 200 A service disc/outside of house after meter) that has 2 ground bus bars & 2 neutral bus bars. Need to remove non insulated strap (bonded to panel) that goes from neutral bus to neutral bus (in sub panel) then jumper neutrals (not bonded) to avoid bonding in sub panel. I was looking for code reference for jumper size & thinking 310.12 @ 2/0 CU or 4/0 AL conductor as 200A service.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I think if you can determine maximum unbalanced load you could use that figure for ampacity on the neutral. Since this is on a feeder supplied circuit the minimum size still would be the same as the minimum required EGC though, so 6 AWG minimum but must be larger if max unbalance current is higher than 65 amps.
I agree if sufficiently bonded to the enclosure no additional jumpers are needed on the EGC bars.
I agree if sufficiently bonded to the enclosure no additional jumpers are needed on the EGC bars.
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