Please help identify this breaker

[Alexis]

Hello,

It seems to be square d, but I can't find anything similar in any searches.. legs look like QO, but I don't think that modern ones would fit..

Thank you!

 

[infinity]

Obsolete Square D type MO-4.

MO-4 Obsolete Square D Circuit Breakers

Antique very old and obsolete MO4 circuit breaker by Square D and Cutler Hammer

breakeroutlet.com

 

[Alexis]

Thank you so much!

 

[jim dungar]

I thought the MO4 family was originally from the 1930s but the earliest panelboard I could find was from the late 40s.

 

[Alexis]

And it looks like there are no modern replacements for this type, right? I can't find even any refurbished ones..

 

[Fred B]

And it looks like there are no modern replacements for this type, right? I can't find even any refurbished ones..

Link in post 2 is a source of refurbished MO breakers.

 

[rszimm]

I’d be hesitant to swap in a refurbished breaker. I wouldn’t think a manufacturer would discontinue a line unless there were some inherent safety issue (looking at the breaker, probably the clips tended to wear out and then arc).

 

[retirede]

I’d be hesitant to swap in a refurbished breaker. I wouldn’t think a manufacturer would discontinue a line unless there were some inherent safety issue (looking at the breaker, probably the clips tended to wear out and then arc).

Most redesigns are for cost reduction.

 

[hillbilly1]

I don’t know about that style, but Square D has retrofit kits for other obsolete breakers that allow a QO to be used. It has bussing that you install to the old buss to adapt. Might pay off to check with your local Square D distributor.