Amp rating with multiple 'mains'

I ran across an older square D box that had three breakers at the top all marked ‘Main Disconnect’. Two were 40 amp breakers and one was a 50 amp breaker. Do I call this a 130 amp service?

If yes, I assume we do the same with Pushmatic service panels?

Thank you,
Jim

What size were the service entrance conductors? Do you have a photo without the cover?

I don’t know the service entrance conductor size. It was more of a general question. Let’s assume the conductors are adequately sized.

Thanks,
Jim

Probably a split bus panel.

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You can’t assume. Depending on the actual setup inside the panel, the service entrance conductor size is one of a few items that will determine the 'Service size" of the system, ‘not’ adding up the breakers.

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Thanks. This is a friend’s house. I should be able to get back in in a week or two and will take a picture of the inside of the panel to post.

While I see plenty of Pushmatic with multiple mains in my service area, this Square D one was a first. I’m not inspecting this home but was wondering how to handle it if I do run across it in a home I am inspecting.

Thank you,
Jim

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Photos would help to get you a correct answer because there are too many variables that aren’t addressed in the photo that you’ve posted. Could be as simple as someone mistakenly installed the stickers.

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Welcome to our forum, Jim!..enjoy participating. :smiley:

That would be one of my questions, too, Rob.

That’s what I was wondering.

Really more info is needed…like with the dead front off as Rob asked about.

If unsure, refer it out to a qualified Electrician. But do not assume, as JJ said.

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Additional photos below. I’ve always just used the main breaker amp rating as the reported service amp. A majority of the time, I am not able to read markings on the service entrance wires.

The original question was ‘How do I determine service amps when there are multiple mains’. Maybe a better question is ‘what are best practices for determining service amps’.

Thank you in advance for your insight and expertise.

Jim

Not only no, but HELL NO!!

You need to learn the proper way to determine the service size.

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#2 SEU Aluminum service entrance cable = 100A rating, the NEC 310 tables are your friend:

That’s why I am here.

Jim

That old meter socket may only be rated for 100A, and that panel box is 125A…

2022-03-29_145743

2022-03-29_150307

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Interesting… I didn’t notice that.

Jim