Understanding this subpanel


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Old 03-01-21, 11:28 AM
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Understanding this subpanel



I have this FPE panel I'm going to be replacing hopefully in the near future.

I'm trying to understand why some of these 20A breakers are twice the width of others. Because the wide ones only have 1 hot wire coming out, that means that it's not double pole, correct?

Is the only 240V circuit the 30A double pole on the bottom right?


I think this was the old 100A main breaker for the house. When the previous owner upgraded to 200A service at the new main panel (not shown), I believe this subpanel was de-rated to 60A(?). All the wiring except for the the double pole looks relatively recent. I have no idea where that 240V goes. The house has central gas heating/AC but that's wired to the main panel. Dryer and stove/oven are gas. I should shut it off, correct?
 
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Old 03-01-21, 11:41 AM
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It's not that some are twice as wide, it's that some are half as wide. The wide ones are standard size while the narrow one are narrow so you can squeeze more circuits into and already full panel. With more modern tandem breakers there are two breakers in one body instead of having and individual thin one. Some call them cheater breakers.

 
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Old 03-01-21, 03:24 PM
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Thanks!

If the wide ones are "normal", why does the panel indicate a pair of numbers for each slot?


 
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Old 03-01-21, 04:00 PM
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I am sorry, I was wrong. I was moving too quickly and didn't pay much attention to your first photo. I didn't notice that it's a Stab Lok. I would wait for our electricians to chime in but I would consider replacing the panel & breakers.
 
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Old 03-01-21, 04:34 PM
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I'm definitely going to replace it as I'm very aware of the potential for the breakers not to trip.

I'm actually just thinking about ditching the subpanel and running all the wires back to the main panel about 100' away. I was just trying to understand why they used a pair of numbers for a single "normal" width breaker.
 
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Old 03-02-21, 10:05 AM
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I believe Pete is still correct that they are just half-size breakers. Or normal and "double-size". From the Stab-Lok panels I've seen, they are just the way they were designed/numbered at the time.

IMO, it's a 50/50 decision whether to install a new sub here, or run your 10 circuits back to the main panel. Cost-wise, it'll be about the same materials cost, I would decide whether you think you'll end up with more future circuits on this end of the house.

Based on the age of the subpanel, you'll probably need to run a new 4-wire feeder to a new subpanel (since this one is most likely 3-wire - I can't quite confirm from the pic).
 
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Old 03-02-21, 01:38 PM
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Thank you for your advice.

I believe I have a 4-wire feed. Maybe this last picture will show it. I think the bare copper wire is bonded to the panel and goes back to the main panel. I'm not sure where the 1 black and 1 taped-white go, though. Could this have been the original 100a line from the main service panel and they are just using the ground as a return? Or maybe it was to an old 240V circuit for AC? I'm a little nervous to stick my fingers in there and move wires around to figure out where those two go.

I'm pretty sure all the work was done w/permits about 20 years ago (in California). This subpanel has me pretty freaked out. In addition to it being FPE/Stab-Lok, I don't like that all the grounding seems to be done with MC conduit, so there's only 1 ground wire going to the ground bus bar in the whole subpanel.




 
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Old 03-02-21, 05:13 PM
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The numbers are for when a tandem is used.
 
 

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