1 meter 2 panels

[qopanel]

I have a question regarding a 400 amp 1phase service that has 2 panels. Out of a 400a underground meter pedestal we installed 2 200a 1p 40 circuit panels each with mains. Each is feed with 3/0 wire and are installed under double lugs in the pedestal. My question is should both panels be bonded and grounded to the water? The way we have it now, is that 1 panel has the neutral bonded in the cabinet and that neutral bar has a 1/0 to the street side of the water. The other panel does not. Both panels have a grounding bushing from the feed and wired to a lug on the back of the cabinet. Hope I made sense.

Thanks
Bob

 

[pierre]

Re: 1 meter 2 panels

Bob

Both of those panels are the 'first point of disconnect' and both are required to be wired as you would wire a service.
Good Luck

Pierre

 

[hornetd]

Re: 1 meter 2 panels

There should be a number four AWG Grounding Electrode Conductor (GEC) run from the second panel's Grounded Conductor (neutral) Buss Bar and tapped onto the first GEC. Both panels neutral buss bars should be bonded to that panel's cabinet.
--
Tom

 

[donnie]

Re: 1 meter 2 panels

If the two panels are the first means of disconnect, you need only to bond the water line to one of the panel's neutral bar location, you are bonding the waterline to the service, not the panels to the waterline.IF you bond both panels to the waterline then you have created a parallel neutral path.

 

[sparkmantoo]

Re: 1 meter 2 panels

in chesapeake mc they want a gec out of each panel to the water line and a wire from each panel to the ground rod. imo this is a wrong application. the panels are not bonded together they are treated as seperate. what happens if one ground fails, the panel that it is connected to does not have its neutral conductor connected to the grounding electrode. both panels are one 400a service not two 200a services. is this correct?

 

[rickg]

Re: 1 meter 2 panels

Bear with me, as I do not have a book here.
There is a picture in the handbook of just this scenario. The bond wire needs to be sized to the service entrance cond size (see table). The hand book shows the bond wire (#2 in this case I think) running from the H2O bond clamp to the panel location, but not entering either panel, & a #4 runs fron EACH panel & connects seperately to the #2 near the panels but not inside either panel. This way if either panel is removed the bonding/grounding is not interrupted.
If I were doing this job, I would land the #2 bond & the #6 ground conductors to a double lug inside the meter base, as our POCO allows the terminations of these conductors in the meter base. This way there would be no grounding/bonding conductors entering either panel. This is called one point grounding/bonding. It also eliminates neutral current from flowing over the bonding/grounding conductors.
Personally, I do not know why you could not run the #2 back to either of the 200 amp panels, terminated under a lug rated for #2, and then run a #4 from the other panel to a bug on the #2 outside the first panel.

 

[ty]

Re: 1 meter 2 panels

To be Code compliant, Tom (hornetd) has it right for this service.

 

[ty]

Re: 1 meter 2 panels

rickg, your last sentence could be done and be Code compliant.