Electrical Questions? Ask an Electrician Online.
There should be a manufacturers name on the panel. What is it?
Square D is still around. You should be able to get that breaker at any home center. The design hasn't changed as far as attachment. The new ones will fit.
Turn it off. If you can take a picture and upload it for review and identification.
That number means nothing to me. I need a visual on the breaker for identification.
Turn it off, go on vacation. When you get back send it and we can continue.
Square D breakers are "QO" prefex the the size 15, 20,30 and so on.