[ThatGoogleGuy]

Hey everyone,

I've been thinking about adding a sub-panel to my house but I realized I don't even know how many amps my main panel is rated for - the main panel is 50 years old and every spot where the amperage was supposed to be written with a pen has been left blank.

If anyone has advice please let me know!

Here is a pic of the panel, and another pic of a diagram in the panel

 

[rjniles]

That is a sub panel. You have a another panel somewhere that feeds this panel and has your main breaker. Most likely near your meter.

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[ThatGoogleGuy]

Unfortunately that's definitely the main panel. Like I said this house is 50 years old and that's the original panel. You can't get any closer to the meter considering it is on the backside of the same wall as this panel.

So any suggestions?

 

[Oso954]

That’s a split buss panel (the 4 two poles at the top). The breaker in the top position on the right is the one that should kill all the lower breakers (the single poles).
It appears that it may be a 60 amp feeding the lower breakers.

I think the model number of that panel may be at the top of one of those 2 large labels. Unfortunately I can’t make them out and your photo Of the left side label clipped the top printing off.

Edit: you are out of space. May have a few amps left over, but not enough to do any good. Between that and no spaces, replace it.

 

[surferdude2]

I clipped this from another source that should be useful;

<snippet>I have an Old Square D QO N-20-412 Main Service Panel. On the inside it states: 125a Mains. Inside the panel on are (4) dual Pole Breakers, (2) top Left, (2) top right. Top Left is a 60amp and has two main leads that go to the center of each row which<snippet>

It looks like your tag states QO 20-412 but verify.

 

[ThatGoogleGuy]

@Oso954 the model numbers it lists are QO 20-412 series E4 and QOBW 20X125-3.

Would it be safe to swap out the 60amp for a 100amp breaker?

 

[ThatGoogleGuy]

@surferdude2 yes mine also says something about 125 mains! What does this mean? I'll post a picture of the other worn out sticker which says this

 

[surferdude2]

It's still a legal panel. You can accomplish a disconnect without having to throw more switches than the code allows (6). Looks like you can do it with 4 as shown.

I'd say it's rated at 125 amps total. The way it currently fed, you can load 65 amps on those four big top 2 pole breakers and 60 amps aggregate on the lower ones.

It's big enough in amperage for most houses and being a Square D makes it good quality. It may not have enough breaker slots and require using tandem breakers if you need to expand it. It has to be approved for those or they will be mechanically rejected.
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[Oso954]

Would it be safe to swap out the 60amp for a 100amp breaker?

No, that position (the tie to the lower bus) is limited to 70 amps max.

(Says so right on the label you photographed.)