Service Multiple Enclosure Bonding

[Zach Williams]

We have a Strip Shopping Center with 400 Amp main disconnect and neutral bonded to the enclosure that feeds 4 tennant spaces. The load side of the main disconnect feeds the line side of 4 meter bases. Each meter base feeds a 100 Amp disconnects for each tennant space. 100 Amp disconnects feed subpanels in the tennant spaces. Meter Bases have neutral bonded to enclosure at the factory. Does the neutral in each disconnect need to be bonded to the enclosure? 100 Amp disconnects are grouped with the 400 Amp Main on the exterior of building.

 

[raider1]

Does the neutral in each disconnect need to be bonded to the enclosure?

No, your service ended at the 400 amp disconnect where you made your maind bond. Bonding the neutral after the main disconnect is a violation of 250.24(A)(5). You will also have to remove the neutral bond at each meter because they occur after the service disconnecting means. You should have an equipment grounding conductor run with the feeders to each meter and 100 amp disconnect.

Chris

 

[mdshunk]

N You will also have to remove the neutral bond at each meter because they occur after the service disconnecting means.

Tricky to do, many times.

I asked a question some months back about this same situation (known as "cold sequence metering"), and the issue went unresolved.

 

[mpd]

the meter enclosure is permitted to be grounded by the grounded conductor on the load side of the service disconnect, look at 250.142 (B) exception #2

 

[raider1]

Tricky to do, many times.

I asked a question some months back about this same situation (known as "cold sequence metering"), and the issue went unresolved.

Agreed, but I don't see where a meter installed after the main disconnect is allowed to be bonded to the grounded conductor.

Chris

 

[raider1]

the meter enclosure is permitted to be grounded by the grounded conductor on the load side of the service disconnect, look at 250.142 (B) exception #2

Thanks, I guess I was just informed of an exception that will allow meters installed after the main disconnect to be bonded to the grounded conductor.

Chris

 

[infinity]

Is 400 amp disconnect fused?

 

[Zach Williams]

Thanks, but...

Thanks, but...

Thank you all for your comments. If 150.1.24 (b) exception #2 permits bonding of the meter base, what should one do with the 100 Amp disconnects after the meters?

Infinity, the 400 Amp disconnect is fused.

 

[Ryan@TeamElect]

How

How

How did u bond the meter base? Let me make sure i have this right...there is a incomming service to a fuseable 400 amp disco. then to all the seperate meter bases, then to seperate disco's. then to the subpanels in the units?

 

[Zach Williams]

Bonded Meter Base

Bonded Meter Base

Ryan, You understand the setup correctly. The meter base is bonded by the manufacturer. To remove this bond, as some suggest, would violate the UL listing.

 

[LarryFine]

Ryan, You understand the setup correctly. The meter base is bonded by the manufacturer. To remove this bond, as some suggest, would violate the UL listing.

Suppose you land the EGC on the bonded meter neutral lug and run an insulated neutral conductor unbroken through the meter and to the individual disco?