Will my panel inside be considered a subpanel, and now be un bonded

Question

I have installed a 200 amp distribution panel w/socket head. Will this be considered my main panel, and my panel inside now becomes my subpanel?

Should my subpanel be unbonded, and 2 lines, 1 neutral, plus ground be provided to the subpanel?

Answer 1

If the new meter panel is feeding the old panel, the old panel is now a subpanel of the new panel, which becomes the main. The subpanel should not bond neutral to ground, but the main panel should.

Answer 2

It depends

On what "loads" are located in the outdoor panel. If no loads are there, then NEC 230.85 lets you pick and choose which one is the "main panel" for grounding/bonding and neutral separation purposes. You must label both breakers with specfic markings depending on your choice.

If there are loads in the outdoor panel, then it greatly depends which loads they are. NEC 230.82 has a list of loads which are allowed on the service side of the main breaker, and those (only) can be in the outside panel while still calling the inside panel the "main panel". That includes things like

• Solar and other auxiliary power supplies e.g. wind or battery systems such as PowerWall
• Generator interlock
• Surge protection
• Power for automatic transfer switches and other control equipment
• Certain emergency loads, e.g. fire alarm
• Voltage measurement instrumentation, e.g. the current meter used in dynamic load management of EV charging

If there are loads in the outer panel not subject to a 230.82 exception, then the outer panel is the main breaker and the feeder to the original panel must be 4-wire (retrofitting ground allowed, see 250.130(C).)