Darryl:
I respectfully disagree with the use of the bonding screws. In general,
there are two panels that require bonding: The service and a separately
derived system. The service needs a neutral-ground bond screw but the
second panel is a sub-panel and must have an isolated neutral.
William
PS: When considering how to bond and feed neutrals to a critical loads
panel, think about how the neutrals are connected in the inverter. Unless
the inverter is a "mobile" unit, the in and out neutrals are connected
together in the inverter. When using an integrated BOS AC cabinet, only
one neutral is required. Therefore one neutral buss is technically all
that is needed for the described scenario. Your inspector may very likely
not be comfortable seeing no neutral buss in one panel. If required, you
can feed the new panel neutral from the inverter or from the service
panel. With proper low impedance connections, they are all the same
potential and complete the circuit path back to the service transformer,
the ultimate duty for a neutral buss.
Wm
At 06:42 AM 5/8/2012, Darryl Thayer wrote:
Locally if you have two service panels next to each other, inspectors want
both bonded and grounded, by allowing a bonding jumper from panel one to
panel 2, and both panesl use the bonding screw, and both have to have a
neutral bus.
From: Corey Shalanski <[email protected]>
To: [email protected]
Sent: Tuesday, May 8, 2012 6:51 AM
Subject: [RE-wrenches] Critical Loads Panel Wiring
Wrenches,
Batt backup system: When placing a critical loads panel directly adjacent
to the main service panel (in the next stud bay), must the neutral and
ground conductors be pulled into the new subpanel? or can only the hots be
pulled? Any Code references would be appreciated.
--
Corey Shalanski
Joule Energy
New Orleans, LA
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