A friend told me his electrician installed a 14-30 outlet using two 40 amp breakers and that it supplied 60 amps. Does this make sense? I have the Tesla 14-30 adapter for my UMC. What amperage setting should I use to charge: 24 or higher?
You friend is (hopefully) confused. If he's correct, than that "electrician" should return his license to the Cracker Jack box from whence it came. As mentioned, the 14-30 UMC adapter will auto select a max of 24 amps
Are these 2 single slot (120V) breakers? Maybe your friend is seeing a duplex (2 slot) 240V breaker and calling it "2 breakers"? If this was wired using two, 240V duplex breakers, than the electrician clearly doesn't even have a Cracker Jack license.
You can't legally run a 14-30 on one (or two) 40A breakers. And it wouldn't supply 60A without bad things happening.
Where did 60A come from, anyway? Why not 40A (breaker rating)? Or 80A (if, God forbid, these are 2 40A duplex 240V breakers in parallel:scared
As ra-san says, most likely the two 110V breakers. Running 60A through a 14-30 outlet would be very dangerous. I'm sure FlasherZ will be here any minute and quote the chapter and verse from code, but fundamentally the plastic and the conductors in the 14-30 aren't rated for that amount of energy and it would most likely simply melt on you - or cause a fire.
I've heard of many L6-30 plugs melting/burning from not much more than 30A continuous. I would think 60A through a 14-30 is a guarantee of a fire.
Thanks. So my friend is likely confused and its two, 15 amp circuits mobiles into a 30 amp circuit. I'm interested in what FlasherZ has to say but it's nice to know the adapter will provide the right amperage.
This is not legal/to code, either. You can't parallel circuits for increased capacity, as you can't guarantee that each side carries their rated share and no more. For example, a loose connection in one of the circuits would increase the overall resistance in that circuit, and cause it to carry much less than half the load, thereby overloading the other circuit.
My guess is it's 2 40 amp breakers tied together, one for each leg of the 120v circuits to make 40 amps at 240v.
Which would still be illegal and a code violation - you can't connect a 14-30 to a 40A breaker. Also you can't use 2 individual single 120V breakers on a 240V circuit. You have to use a duplex 240V breaker.
As an aside, there is such a thing as a 14-60. It looks like a 14-50 with the neutral (middle blade opposite ground) rotated 90 degrees. It's a somewhat rare beast (I've never seen one in residential). There is no Tesla adapter for it.