I have 2 siemens circuit breakers that won't reset. How can I do

Go to any home store and ask them, they will have the breaker or one to use as a replacement

He is correct. I'll not go into the particulars but the fact is, you have two separate circuits connected to the same breaker. Separate the two circuits by installing another 15-Amp breaker. Although I understand your situation, please understand wire gauge and electrical amperage are two different animals. Breakers are rated in Amperage and electrical conductors are sized by wire gauge. That said, the 20 gauge wire you speak of is actually a 12 gauge conductor and the 15 gauge wire as you say is a 14 gauge conductor. Have a good day.

Turn off all other breakers. And try reset again.
3-phase solid state breaker from Siemens
Contact siemens:
http://www.siemens.com/entry/cc/en/
Unfortunately the Siemens site does not show results for WLSF320, but has results for solid state circuit breaker:
http://www.siemens.com/corp/apps/search/en/index.php?q=solid+state+circuit+breaker&lang=&site=siemens_c_ww&lr=lang_en&as_filetype=&client=siemens_f_ww
Otherwise I cannot find .pdf file to help more.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

yes it will, you need to always make sure that you put the same brand in the panel box, good luck

Sounds like a loose connection or overloaded breaker, Please call a Electrician due to high voltage in box

I would not go to larger breaker size until I knew why 15 amp breaker is trippingIf you find out that 15 amp breaker is tripping because it is being overloaded or that breaker is getting weak. Then I would replace breaker with the same size because they may have wired some with 14-2 wire instead 12-2, I would not feel comfortable pulling 20 amps, on 14-2 wire. That is my suggestion for what it's worth. Thank you.

This does not appear to be an issue with the current recall action. (More info here: http://www.usa.siemens.com/pluginrecall )

Please contact an authorized electrician for assistance diagnosing your issue.

it is still detecting an overload in the circuit. Take the black wire off the breaker and see if it will reset. If so then you will have to trace the wires down to find the short circuit. If it doesn't reset then the breaker is bad

YOU CAN CALL ITE FOR A DEALER NEAR YOU

this is a double pole circuit breaker that is used for a 240 volt device the bar in the middle is to shut down at the same time you can take it to a hardware store to replace it but the bar is factory made siemens is one common breaker or there might be a substute they can give you also