We were at a party over the weekend and lady asked me to look at something for her in the fuse box (ha, of all people!) she tells me this breaker was sparking and buzzing. Turns out it was a Siemens QT 4-20 plug in that wasn't even mounted under the clip, It was just pushed onto the buss bar and buzzing away! The lady had already taken the dead front off and was showing my how she could just pull the quad breaker off the main buss, and she does! I'm like "stop, please dont do that, your going to kill yourself!" I looked at it when she handed it to me with its 12g wires still in it and the slots the buss rails fit into were cracked and burned. Told her it needed to be replaced as there was no retention mechanism left in (small spring wire broke out of it and was laying on the bottom of the can) and turn the 200A main breaker off if you do anything in here (its a new remodel and the panel is only 1.5 years old. I think the guy installed refurb or used breakers. They were discontinued Murrays but Siemens now took that line over and Home Depot didnt stock it (4X20 with the center 2 under a common clip) but could get it special order.
I remedied my problem by plugging the A/C unit into an outlet in the heater closet, thats on its own circuit as the centreal heating wont be used for a good while. LA county registered its hottest day in history saturday in Woodland Hills, 121F. That's smokin......
