electrical breakers

You should find them at HD. Pull one as sample, or take a picture on your phone.
Pay attention to the connector slots. Some looks the same at first look, but have cross slots and breaker without them will not fit.
Codes require all the breakers on the panel to be the same brand, but real life proved that not to be important.

You may have to order one on line. I could not find a 15/20 breaker at Home Depot, Lowes, or large hardware store. Googled the model number on the side of the breaker, found numerous sources, and ordered one.

When I bought my WFCO 8900 series Power Distribution Panel in 2009 I didn't realize they didn't come with breakers. I was able to find all I needed at LOWES... They had the full size, half size, and duals... My panel has five full slots to use so I got the main 30A full size and all of the remaining four full size slots were filled with eight half size breakers. I went with four 20A and four 15A sizes... It always amazes me that when you add up the installed breaker sizes they never are anywhere close to the main circuit breaker rating hehe... Haven't tripped my 30A Main breaker yet using my 15A and 20A circuit breakers...

Roy Ken

WFCO's online manual lists what breakers will fit their converter.

The required tandem style breaker is readily available everywhere. Different brands are interchangeable. For example, our WFCO has factory Square D and Seimens breakers that I added. The face of a breaker has the series/type of breaker it is - HOMT, Q, QO, etc. The amp rating for a tandem breaker would be "3020". If you aren't sure what to order strictly by the correct numbers & letters only, the easiest thing to do is take it to a store and get them to match it. Or go to an electrical wholesaler. You *could* take a photo with your phone but the lettering is teeny weeny and barely readable to the naked eye. WFCO should have a list of breakers that can be used on their website.

You don't have to use a tandem breaker as long as you have enough space in the panel. You could use a 20 amp breaker and a 30 amp breaker. The 30 amp breaker is the main breaker and the 20 amp is usually for the AC unit.

These are sometimes called a tandem and sometimes a duplex breaker. Note well that you want a tandem breaker that is single pole 120 volt and not a 2-pole 120/240 volt one (with tie bar) like you'd find in a house.

Out of curiousity, why are you needing a new 3020 amp breaker?

Below is a Square D "HOMT3020" and Seimens "Q3020" tandem 30/20 amp breaker.

I ordered a 30/20 and a 20/15 from home depot's website. It was free next-day ship to store, but not available from the store itself. Square-D HOMT type.