Thread: Panels

I found this at my inspection today and I am not sure about a couple of things. First the two exterior A/C compressor/condenser units are fed from an exterior panel (picture "ACpanel"). It is fed from a distribtion panel by a 90 amp breaker (pictures "panel1" & "panel2"), why is the neutral loose in exterior panel (ACpanel)? Also the house has a 200 amp main that feeds the first floor distribution panel, that panel feeds a panel in basement with a 100 amp breaker. That's a 90 amp breaker (toAC) and a 100 amp breaker in same panel. It just seems wrong. I usually see two breakers at main service panel feeding A and B panels.

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Tom,

Let's start this way:

What is the service equipment? You are only showing two panels, no service equipment.

Regarding the 240 volt only a/c panel, that neutral needs to be connected to an isolated neutral terminal bar, and the neutral conductor (white) in the ground bar needs to be connected to that isolated neutral terminal bar too.

The ground terminal bar in that panel needs to be bonded to ground. That the existing ground terminal bar would be isolated from ground if the ground bond strap was removed, making a good isolated neutral terminal bar. Of course, the ground conductors in that terminal bar would need to be moved to the new ground terminal bar (see below).

Which means a ground terminal bar would need to be installed elsewhere in that panel, wherever there is a pre-made hole for a ground screw to attach the ground terminal bar to the enclosure.

That would make the 240 volt only a/c panel into a 120 volt / 240 volt panel.

Okay to that point.

What about the service equipment? And any other questions?

Jerry, The service equipment is 200 amp panel located next to meter. It is feeding the panel in two pictures. I don't know how to calculate if the panel in pictures is overloaded.

Originally Posted by Tom Rees

I don't know how to calculate if the panel in pictures is overloaded.

Are the mains tripping?

If not, they are not all that overloaded.

If you really need a "load calculation", then I would recommend an electrical contractor come out and do a load calculation on the house.

Thanks Jerry.