Charging On 6-50

[juls_esp]

hey guys
been getting quotes for 14-50 and hpwc installs were about 1k plus just for labor
anyhow i have been doing some reading the past few days on my options we drive about 30miles a day
we have a 6-50 plug however it is on a 30amp breaker, this plug was here before i bought the house
i know i can buy the 6-50 adapter from tesla but umc will pull 32 amps and will be an issue
so this is what i did instead

purchased 6-50 to 6-20 adapter , bought a duosida 16amp
my expectation is i should get 15mph charging
would running a 16amp charger on a 30amp circuit give me any problems?

it seems all the electricians in my area once they hear tesla the price starts at 1k to install hpwc

 

[AlanSubie4Life]

hey guys
been getting quotes for 14-50 and hpwc installs were about 1k plus just for labor
anyhow i have been doing some reading the past few days on my options we drive about 30miles a day
we have a 6-50 plug however it is on a 30amp breaker, this plug was here before i bought the house
i know i can buy the 6-50 adapter from tesla but umc will pull 32 amps and will be an issue
so this is what i did instead

purchased 6-50 to 6-20 adapter , bought a duosida 16amp
my expectation is i should get 15mph charging
would running a 16amp charger on a 30amp circuit give me any problems?

it seems all the electricians in my area once they hear tesla the price starts at 1k to install hpwc

The breaker doesn’t matter. You need to know the wire gauge to determine how to proceed. They may have installed a lower amp breaker just because it is slightly safer - or they may have done that because the wire gauge is insufficient to support higher. (But then they violated code by putting a 6-50 outlet on the circuit.)

You need 6AWG (8 AWG in conduit is also ok but I wouldn’t do that) for a 14-50 or 6-50 outlet, as I recall.

If the wire gauge is lower than that you have problems with the current outlet.

For the 30A breaker you have, you can only draw 24A continuous (80% rule), until you understand the wire gauge (I would figure this out no matter what). You should not do this by limiting in the car and using a 6-50 adapter. It may forget and then it becomes a hazard if the car draws 32A. Either have the outlet replaced with a 30A outlet or install a Wall Connector dialed back to the 24A setting.

But mostly just figure out the wiring situation before figuring out how to proceed. It is possible you just need to swap breakers if the wiring is 6/2.

 

[wws]

You could also replace the 6-50 receptacle with a 6-30. Unfortunately Tesla doesn't sell a 6-30 adapter for the UMC, but evseadapters does:

NEMA 6-30 Adapter for Tesla Model S/X/3 Gen 2

 

[AlanSubie4Life]

You could also replace the 6-50 receptacle with a 6-30. Unfortunately Tesla doesn't sell a 6-30 adapter for the UMC, but evseadapters does:

NEMA 6-30 Adapter for Tesla Model S/X/3 Gen 2

They sell 10-30 and 14-30 adapters.

EDIT: but yes, these require a neutral. Which probably does not exist.

 

[eprosenx]

hey guys
been getting quotes for 14-50 and hpwc installs were about 1k plus just for labor
anyhow i have been doing some reading the past few days on my options we drive about 30miles a day
we have a 6-50 plug however it is on a 30amp breaker, this plug was here before i bought the house
i know i can buy the 6-50 adapter from tesla but umc will pull 32 amps and will be an issue
so this is what i did instead

purchased 6-50 to 6-20 adapter , bought a duosida 16amp
my expectation is i should get 15mph charging
would running a 16amp charger on a 30amp circuit give me any problems?

it seems all the electricians in my area once they hear tesla the price starts at 1k to install hpwc

To pile on what @AlanSubie4Life mentioned:

You need to determine what the wire gauge is, whether it is copper or aluminum (virtually guaranteed to be copper), optimally we would know what type it is (romex? / NM cable), and we need to know how many conductors it has. A 6-50 just requires two conductors for "hot" and one for ground.

If you discover that the wire is only 10 gauge copper (good for a 30a circuit) and there are only two conductors plus ground, then you are a little bit stuck. Tesla (maddeningly) does not make a 6-30 adapter. They do make 10-30 and 14-30 adapters, but both of those require a neutral wire. So basically, if you want to re-use the existing wiring (and there is not a neutral wire hanging out there unused currently) you either need some kind of 3rd party adapter and say the Tesla 14-30 adapter (which will then limit the charging speed properly), or this integrated unit (still 3rd party and not UL rated): NEMA 6-30 Adapter for Tesla Model S/X/3 Gen 2

I am not a massive fan of the 3rd party adapter since it is not UL rated and I question whether it will adequately detect excessive receptacle heat, but it may be the best option at this time. I am very disappointed that Tesla does not offer this (nor a TT-30 adapter which is useful for RV receptacles).

Note that for *temporary* use you could buy the 6-50 adapter from Tesla and just dial the amps back to 24, but I do not recommend this for any kind of long term usage as you are depending on humans to set things right (or the software to hopefully remember each time based on geo data), which is always fraught with peril.

You want to be using a Tesla adapter for the Mobile Connector which properly restricts the amps to a limit safe for the circuit.

 

[juls_esp]

thanks for the responses
i looked at the breaker at its an 8awg, reading the exterior of the wire is about as far as i am going to go as i really dont know anything.. i have read about getting the 6-50 adapter for the umc,
reasoning behind the 3rd party 16amp max is it would be safer on 30amp circuit? also it would allow me to keep my umc in the car at all times. I am still waiting on my car hence all this time researching ;(

 

[jsmay311]

You already bought a 16A EVSE?

If it were me, I probably would’ve bought the 6-30 UMC adapter for $85 from EVSEAdapters.com and then replaced the 6-50 outlet with a 6-30 outlet.

Or if you’re not comfortable using a non-Tesla-certified adapter, get the 6-20 UMC adapter from Tesla for $35 and install a 6-20 outlet and replace the 30A breaker with a 20A breaker. That would charge a bit slower, but it would be plenty fast for your needs.

 

[eprosenx]

The breaker doesn’t matter. You need to know the wire gauge to determine how to proceed. They may have installed a lower amp breaker just because it is slightly safer - or they may have done that because the wire gauge is insufficient to support higher. (But then they violated code by putting a 6-50 outlet on the circuit.)

FWIW, actually *technically* installing a 6-50 on a 30a circuit does not violate code *if* "The load to be served" is equal to or less than the circuit ampacity. This is weird, but it is my interpretation of the code (I have posted extensively about this in other threads here - but I don't have a link handy to the right one - this thread has some info Laundry list of proposed changes to the 2017 NEC).

There are a lot of welders with 6-50 plugs on them (since it is a really common receptacle type for welders) but a lot of them may never need more than a 30a circuit. I actually have never dove into this, but I think welders may be allowed on lighter gauge circuit wiring since they are not typically continuous duty devices (you have delays between bursts of welding).

 

[davewill]

thanks for the responses
i looked at the breaker at its an 8awg, reading the exterior of the wire is about as far as i am going to go as i really dont know anything.. i have read about getting the 6-50 adapter for the umc,
reasoning behind the 3rd party 16amp max is it would be safer on 30amp circuit? also it would allow me to keep my umc in the car at all times. I am still waiting on my car hence all this time researching ;(

Good news. You should be able to change to a 40a circuit breaker, then use the 6-50 adapter directly. I've used that exact setup (8awg wire, 40a circuit breaker) to charge my cars for years.

To answer the question that no one else did, yes your plan with the 16a Duosida would work just fine, BTW.

 

[eprosenx]

You already bought a 16A EVSE?

If it were me, I probably would’ve bought the 6-30 UMC adapter and replace the 6-50 outlet with a 6-30 outlet.

Or if you’re not comfortable using a non-Tesla-certified adapter, get the 6-20 UMC adapter from Tesla for $35 and install a 6-20 outlet. That would charge a bit slower, but it would be plenty fast for your needs.

FWIW, if you did get a 6-20 receptacle you also need to replace the breaker with a 20a breaker (a 20a receptacle on a 30a breaker is very much a clear code violation).

Oh, and I forgot to mention before that one option to max the capacity of the installed wire and to not have any of the 3rd party adapter / UL rating issues as discussed is to buy a Wall Connector. It does not need a neutral wire and it can accept any size circuit from 15a to 100a. But it is kind of expensive for this use case and kind of a waste to only get 24a (on a 30a circuit) of capacity. But it does check all the boxes...

 

[juls_esp]

thank you all for the responses
15MPH charging is more than enough for my needs at this time.
the 40amp upgrade is something i might look into in the future, for now i just want my car delivered as my credit card is not safe with amazon and i am buying more things than i probably need

 

[eprosenx]

Good news. You should be able to change to a 40a circuit breaker, then use the 6-50 adapter directly.

To answer the question that no one else did, yes your plan with the 16a Duosida would work just fine, BTW.

Yes! What @davewill says! With 8 AWG you can upgrade to a 40a breaker and it is totally code legit to put a 6-50 (or 14-50 if you had a neutral wire) receptacle on the circuit. Then just buy the 6-50 Tesla adapter and you are good to go to charge a 32a! (the max the Mobile Connector supports).

Note that if you do go with the 16a Duosida you would probably want to install a 6-20 receptacle and a 20a breaker as I am not sure what code/UL has to say about connecting a 20a device into a 30a (or greater) circuit. I could see scenarios where the device (the Duosida) relying on the circuit breaker to clear faults and so you would want them matched (though I really don't know the details here).

I would totally go with the 50a receptacle though on the 40a circuit and use your included Mobile Connector. That is a great solution. (not that it might be worth labeling that receptacle for the next guy with something like "40a circuit" so they know not to try and pull the full 50a- this is not a code requirement but it is a good idea).

 

[AlanSubie4Life]

FWIW, actually *technically* installing a 6-50 on a 30a circuit does not violate code *if* "The load to be served" is equal to or less than the circuit ampacity.

Ah, I think I remember you saying this. I can’t keep it straight, especially since logically this exception (in retrospect) makes no sense these days with a bunch of EVs pulling 40A...just makes things dangerous.

But anyway, OP can just swap their breaker as you and @davewill say.

One more question while on the topic: I thought ampacity of 8AWG in conduit could support 50A breaker if it is not Romex? Is that right? Looks like it just needs the 75C rating? I can’t keep it straight.

So if the OP has THHN or one of the other wire types in conduit could they have a 50A breaker? Though there would be no benefit with the UMC Gen 2...

Obviously we don’t know what the OP has exactly so 40A is the “safe” bet - and all that is needed.

 

[jsmay311]

FWIW, if you did get a 6-20 receptacle you also need to replace the breaker with a 20a breaker (a 20a receptacle on a 30a breaker is very much a clear code violation).

Good catch. (I had edited my post to include this detail, but not fast enough!)

 

[davewill]

...
Note that if you do go with the 16a Duosida you would probably want to install a 6-20 receptacle and a 20a breaker as I am not sure what code/UL has to say about connecting a 20a device into a 30a (or greater) circuit. I could see scenarios where the device (the Duosida) relying on the circuit breaker to clear faults and so you would want them matched (though I really don't know the details here).

...

I heartily disagree. There's no reason to change anything. Just use the adapter you already bought.

 

[AlanSubie4Life]

I heartily disagree. There's no reason to change anything. Just use the adapter you already bought.

I've edited this a fair amount since I got confused about the disagreement...

The OP has to change the breaker, to be fair. Either to a lower breaker (20A with Duosida) or a higher breaker (40A with UMC) depending on which way they go.

Why do you disagree with lowering the breaker to 20A? For most things it's good to lower the breaker to match the device, in my mind. The point is that if there is an actual fault it'll blow a bit sooner. Might be a small set of cases where this is actually a problem, but they have different rating breakers for a reason, and it's not JUST to prevent the wires from getting too hot and melting. Lower rating breakers also potentially prevent the EVSE device itself from catching fire.

The reason to use the 3rd-party EVSE is so that you can keep the UMC in your car and not fiddle around with it. For some people it's important to be sure they have it in the car. It's easy to forget it if it is plugged in in the garage!

However, for most, just keeping the UMC in the garage is just fine. Personal preference for the most part.

 

[davewill]

... Why do you disagree with lowering the breaker to 20A? For most things it's good to lower the breaker to match the device, in my mind. ...

It may be in your mind, but it's not any sort of customary practice. We plug low amperage appliances into outlets of higher amperage most of the time. There's no need to change the breaker just because he's using a 16a EVSE on a 30a circuit. One of my pet peeves about this place is that the simplest questions get turned into endless suggestions that half the time are pretty meaningless. I'm surprised that most of the newbies that come here don't just give up on buying an EV.

In this case, the OP has a perfectly usable setup he just paid for and doesn't need to do electrical work at all, unless he's interested in upgrading, which he doesn't seem to be at this time.

 

[juls_esp]

thanks for all the help fellas, its not my first time joining car forums and i know how much knowledge i will gain just from reading and hanging around... on another note i just got the text that i will be taking delivery next week

 

[AlanSubie4Life]

There's no need to change the breaker just because he's using a 16a EVSE on a 30a circuit. One of my pet peeves about this place is that the simplest questions get turned into endless suggestions that half the time are pretty meaningless

Sure, I would say that if the rest of the circuit is good to 30A it is just fine.

I will say that the original question did confuse me, just the way it was posed, and I originally didn't even understand what he had purchased - however:

1) The OP appeared to want to get the EVSE (Duosida) only because he was concerned about the current draw with the 6-50 adapter with the 30A breaker (which is definitely a problem). Maybe he also wanted another charging option so he could keep the UMC in the car, but he did not say so originally.

2) I proposed that once he knew the wire gauge, he'd know how to proceed. If the circuit was good to 40 or 50A, then the 6-50 adapter from Tesla can be used with the UMC Gen 2. All that would be required would be a breaker change to 40A, or 50A, depending on the situation.

The lowest overall cost would be to get a new 40A breaker, swap it himself, return the Duosida & the adapters he got, and purchase the Tesla 6-50 UMC Gen 2 adapter.

It's true that with what the OP bought, he had a perfectly usable setup with no electrical work, just with what he bought. And he can keep the UMC in his car. He'll probably still want to get a 14-50 adapter for the UMC even if it is useless at home. (Depends on road trip plans obviously.)

The Duosida 16A is not what I would choose personally, since the circuit he has allows charging twice as fast at home. I would have purchased a different EVSE and replaced the breaker (which for some people would require an electrician - but is one of the simpler things a homeowner can do), and would keep the UMC in my car. But either way is likely to be just fine.

Another option would be for the OP to keep everything he has, replace the breaker with a 40A breaker, use the Duosida on it with the adapters, buy the 6-50 & 14-50 adapters from Tesla, and then when he needs fast charging at home, can use the UMC in those special cases. And the 14-50 would be for road trips.

There are so many possibilities. But we did have to determine the wire type first just to be sure.

 

[eprosenx]

It may be in your mind, but it's not any sort of customary practice. We plug low amperage appliances into outlets of higher amperage most of the time. There's no need to change the breaker just because he's using a 16a EVSE on a 30a circuit. One of my pet peeves about this place is that the simplest questions get turned into endless suggestions that half the time are pretty meaningless. I'm surprised that most of the newbies that come here don't just give up on buying an EV.

In this case, the OP has a perfectly usable setup he just paid for and doesn't need to do electrical work at all, unless he's interested in upgrading, which he doesn't seem to be at this time.

So I am a little out of my comfort zone here since I have not researched deeply this exact topic, but I was just calling out that I am not sure it is a great idea to be using a 16a EVSE on a 30a circuit.

Yes, you are right, we use very low amperage appliances on outlets capable of a lot more amps, but the key here is that the appliance is designed with knowledge about the amperage of the circuit in mind.

Here in North America if you put a NEMA 5-15 plug (or 1-15 plug which is the non-grounded version) on your appliance cord you can expect it will be plugged into either a 15a or a 20a breaker/fused outlet. So if your appliance cord has a short in it, the cord must be able to flow enough amapacity to cause the breaker/fuse to blow. You do *not* have to deal with the situation of that being on a 30a circuit.

In the UK because they have fuses in the plug of every appliance in order to deal with the fault-in-the-cord issue. This allows them to have much higher amperage circuits (32a “ring mains” specifically).

So even though your Apple laptop adapter needs less than one amp of current at 120v, it still has a wire capable of significantly more amps for the reason I describe.

A similar thing applies if you use the adapter described to plug an EVSE in that has a 6-20 plug on it into a 30a breakered circuit. That EVSE was built under the assumption that the circuit will open if more than 20 amps is drawn.

Will this work? Yes. Is it to code? Well actually, NEC only deals with up to the receptacle, so yeah, it might be up to code. But I think the issue is with UL rating for this application.

Odds are you will never have an actual issue with this setup, but I would not be comfortable with it as my permanent home charging solution. Do it right is my philosophy for something that could burn your house down.

Also, I would totally want the ability to charge at the full 32a. It is a very simple upgrade to get the full 32a capacity! ;-) I would not want to have to use the J1772 adapter at home every day either.