I ran 2 wire #6 'romex' to my 6-50 sockets (two circuits) in my garage. In my case I carried the 125 ft roll of wire into my attic then pulled from there down to the garage and carried the other end to the end of the house where it runs down the outside (2 story) to the panel. Not having a neutral saved me a bunch of weight and so made the job much easier. Not sure what I'll do when the CT gets here. Maybe sell the 3.
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NEMA 14-50 is dead - all hail NEMA 6-50
- Thread starter eprosenx
- Start date
I’d order the NEMA 6-50 adapter from Tesla and have your electrician replace your existing 70 amp breaker with a 50 amp breaker. That will give you the proper protection for the 50 amp receptacle, assuming the wires are sized correctly. Since your electrician will be there, have him verify that the wires are the correct size rather than assuming and hoping for the best. You should be able to have him in and out for a minimum service call charge and the cost of the new breaker.
Oh, one more thing - check the brand name on the existing receptacle. If it’s a Leviton or other cheap ($15-30) hardware store model, replace it with a Hubbell or equivalent $50-70 model. The Levitons are a fire hazard.
The basic problem here is that if a Nema 5-15 (standard ubiquitous 120 volt receptacle) is tapped off of a 14-50 (which most inspectors will not allow anyway), it has to be overcurrent protected at 20 amperes maximum....
Companies sell various 'combo' outlets which - if it is intended to tap them onto just one circuit, also have a plug fuse or circuit breaker (rated at 15 or 20 amperes) to protect the smaller receptacle.
I'm not seeing how that's relevant to this. We are talking about the weird requirement of whether the breaker needs to be GFCI type or not, depending on the supposed use of the outlet.My combo box has separate breakers - a 20amp for the standard plug and a 50amp for the 14-50. Upstream from the box (at the panel) is a 50amp breaker for the circuit.
You will have to use an angle grinder on the right-angle piece of the 14-30 Ground pin. 14-30 right-angle will not fit in 14-50 socket, 14-50 is flat and will not fit in 14-30.
Also, thoroughly remove all metal shavings from the plug before using. Shorting ground to one or more hots is strongly discouraged.
Fortunately an angle grinder was available when I discovered this.
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I'm pretty sure this was just a small brain lapse, but I do want to correct this information for others reading it. The ground pin is the round one. You're talking about the neutral pin, actually. And yes, with the Tesla 14-XX type of plugs they do not use that neutral pin at all, so it's fine to cut that pin completely off. I have done that with my 14-30 adapter so it can plug into my standard 14-50 extension cord.
NOVA-10
Member
Im having a dedicated line run into my garage. Electrician recommended the 6-50 over 14-50, as I was planning to upgrade to the Tesla Wall charger in the near future. Is there any reason for this?
You don’t need to run a neutral wire. I would want the natural wire because it allows flexibility I. The future. Also, if you gonna get the wall charger to get higher charging speed, you need to make sure he is running #6 thhn or equivalent. 6-3 Romex will not work, and I have a feeling your bro wants to run 8-2 romex, which is fine for a 6-50 but not for the wall charger, which can charge at 48 amps.
NOVA-10
Member
I ran 6/2 to both of my 6-50's in my garage. Turns out that I only charge at 20A and its plenty. I would not buy a wall charger. I just don't need it. I know of no EVs that require a neutral.
None of them do or ever will. Neutral is only there in these circuits for appliances that need to have both 240V and 120V supplies, because they have some that's high draw like a heating element and other things that are low draw, like light bulbs or motors. With electric car charging, it's just a very straightforward thing of deliver the highest power connection to transfer energy in as fast as possible, so it only needs the higher voltage. There is no reason to need the lower voltage.
TheRFMan
Member
8/2 Romex is usually NOT fine for a 6-50 under most conditions. 8/2 Romex is only rated to 40A. Since there is no specific receptacle for 40A circuits, there is an allowance in the electrical code to use 8 gauge wire with a 40A breaker in the panel connected to a 14-50 or 6-50 outlet. The outlet needs to be labelled as being a 40A circuit. Even then, I've heard of inspectors not allowing this practice.
The risk is that most devices with a 6-50 or 14-50 plug assume that they're connected to a 50A circuit, and could draw up to 40A continuously. The Corded Mobile connector will do that for sure. Drawing 40A continuously through 8 gauge Romex would not trip the 40A breaker, but would be against code and would heat up the wire, potentially enough to be a hazard.
Max ampacity and over current protection are two different things.
A 50 amp circuit breaker can only handle a circuit with the maximum current draw of 40 amps (50*.8=40)
8 awg nm cables maximum current draw is 40 amps. Not 80 percent of 40 amps.
However, an EV is a continuous load which has special requirements which is why the mobile connector only charges at 32 amps. Which makes using 8-2 fine. But not ideal.
maximum current draw is max ampacity. Maximum over current protection is the breaker size.
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The Gen2 UMC only draws up to 32A for the above reason. It's 80% of 40A. The Gen1 UMC though can draw 40A. I bought used Gen1 UMC's for my installation but like I said, I found I did not need 40A. 20A is fine for me. At that rate it can completely fill my 75 kWh car in about 16 hours. That would cover about a 200 mile daily commute.
JohnnyEV
Member
This is correct I went with the Gen 1 UMC for my build and it runs at 40A on a 14-50 with 50A breaker. 2021 Model Y LR 38MPH charge and 2021 Model 3 P 36MPH charge.
TheRFMan
Member
No, the Gen 2 Mobile connector is limited to 32A as a design choice, perhaps to save costs. Gen 1 and the corded mobile connector still sold today will draw 40A. And what if someone plugs in another appliance such as a welder or heater that draws 40A?
Be safe, if using Romes, run 6 gauge for a 6-50 or 14-50. 8 gauge THHN in conduit is also OK.
The reason for the 32A on Gen2 is because the Gen1 was starting fires where the 50A outlet was installed on a 40A circuit.
I doubt anyone needs more than a 32A charge rate. For the 75 kWh cars that's under 8 hours from stone dead.
I doubt anyone needs more than a 32A charge rate. For the 75 kWh cars that's under 8 hours from stone dead.
Outlets can melt even on a proper 50A circuit and wire. Drawing 40A just makes it melt sooner than it will at 32A.
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