The GFCI self test in the UMC (or HPWC, both do it) is probably upsetting the GFCI breaker. If it were me, I'd replace it with a non-GFCI breaker.@eprosenx Once again thank you. Yes, the breaker is from 2008 when the house was built. It was originally for a Hot Tub which I have removed a couple of years ago. The breaker was turned off for a couple of years and I have now just wired the 14-50 into that breaker after unwiring the run that went to the Hot Tub. The breaker and panel are located in my basement which is dry.