Temporary charging solutions before a wall charger install

[dsgerbc]

Hi all.
Ordered a P3D couple of days ago, thinking about how I'm gonna charge it for the first few weeks. Probably installing a wall unit over the next few months, but gotta charge before then

I have two weird-ish pre-existing 240V outlets. Both are on a 30A breaker. Both seem to have passed local inspections when installed/built/sold. Which one should I use? Or neither?

1) Garage has a L14-30P plug (for a generator, with a manual interlock plate on the panel) 10ft off the main panel through a 3/4 metal conduit on a 30A breaker, uses 8ga wires.
Residential charging rates.
2) Free standing barn (10y.old purpose built by PO with all the wiring done then) has another 6-50 welder plug still on a 30a breaker, but only has a 10 awg 4-wire solid copper romex running maybe 40ft from the panel over the attic and then in a flexible conduit. The upside of this location is that this building is on a business account and gets electricity about 20% cheaper.

Options
a) Undo the manual interlock on 1) for a while, get an L14-30R to 14-30 adapter, buy the Tesla 14-30 plug, charge automatically at 24A.
Cons: Undoing interlock. Extra adapter

b) Install a 14-30 plug instead of the 6-50 plug on 2).
Cons: Still 10 AWG all-copper wire. Is it enough?

Or should I go with
c) Buy a 6-50 Tesla plug (14-50 is more popular but no longer included and out of stock online) and install a 6-50 outlet?

Thoughts?

 

[SSedan]

The 14-30 is a standard dryer outlet, good adapter to have anyway.

 

[eprosenx]

Hi all.
Ordered a P3D couple of days ago, thinking about how I'm gonna charge it for the first few weeks. Probably installing a wall unit over the next few months, but gotta charge before then

I have two weird-ish pre-existing 240V outlets. Both are on a 30A breaker. Both seem to have passed local inspections when installed/built/sold. Which one should I use? Or neither?

1) Garage has a L14-30P plug (for a generator, with a manual interlock plate on the panel) 10ft off the main panel through a 3/4 metal conduit on a 30A breaker, uses 8ga wires.
Residential charging rates.
2) Free standing barn (10y.old purpose built by PO with all the wiring done then) has another 6-50 welder plug still on a 30a breaker, but only has a 10 awg 4-wire solid copper romex running maybe 40ft from the panel over the attic and then in a flexible conduit. The upside of this location is that this building is on a business account and gets electricity about 20% cheaper.

Options
a) Undo the manual interlock on 1) for a while, get an L14-30R to 14-30 adapter, buy the Tesla 14-30 plug, charge automatically at 24A.
Cons: Undoing interlock. Extra adapter

b) Install a 14-30 plug instead of the 6-50 plug on 2).
Cons: Still 10 AWG all-copper wire. Is it enough?

Or should I go with
c) Buy a 6-50 Tesla plug (14-50 is more popular but no longer included and out of stock online) and install a 6-50 outlet?

Thoughts?

So if that generator inlet is done right it should be a make plug on the outside, not a female, so that is probably an issue right?

Can you post pictures of all of this? (Receptacles, panels, etc...)

For temp use I personally am willing to cut a few corners if the person operating it is knowledgeable and it is a controlled environment (no kids, etc...)

I have a “temporary Tesla charging setup” that I will just take a panel cover off and plug the temp breaker in direct to the panel. But that is not safe or comfortable for everyone.

In your case just getting a 6-50 adapter and manually setting charge current to 24 amps (80 percent of the 30a circuit) might be the path of least resistance. I never recommend this as a permanent solution (relying on manually setting amperage down in the car) but on a temp basis with a knowledgeable person it may be fine.

If indeed it does have two hots a neutral and a ground wire to that location, you can trivially swap it to a 14-30 and get the right Tesla adapter and then it will be perfectly safe in all conditions.

Some background reading for you that I wrote:
How Should I Charge My Tesla? – Article625.com

Welcome to Tesla ownership!

 

[ivan801]

I would opt for whatever is easiest to configure. Sounds like L14-30R is your best option. But instead of using an adapter, can you convert the plug into 14-30 to avoid using an additional adapter? Extra 20% cost of electricity should not add up to all that much. Also, consider where you will want to park the car: I would guess in the garage and not the barn.

 

[eprosenx]

To more specifically answer your questions:

Options
a) Undo the manual interlock on 1) for a while, get an L14-30R to 14-30 adapter, buy the Tesla 14-30 plug, charge automatically at 24A.
Cons: Undoing interlock. Extra adapter

b) Install a 14-30 plug instead of the 6-50 plug on 2).
Cons: Still 10 AWG all-copper wire. Is it enough?

Or should I go with
c) Buy a 6-50 Tesla plug (14-50 is more popular but no longer included and out of stock online) and install a 6-50 outlet?

Thoughts?

a). Undoing the interlock creates a serious hazard in multiple ways if you don’t replace the inlet plug with a receptacle. I have been known to do hacking things under closer supervision for very short periods of time, but this creates very real hazards (to utility workers too if you backfed in a generator later without the interlock). This could be made perfectly safe by swapping the plug for a receptacle and removing the interlock.

b). 10 awg is fine for a 30a circuit. This is a perfectly acceptable solution.

c). A 6-50 adapter and receptacle is a perfectly great way to charge a Tesla. With a UMC Gen 2 you should have that at least on a 40 circuit (wire abs breaker). But really any new 6-50 receptacle install should really have 50a wire and breaker.

But as mentioned, you could just order this adapter and use it as is TEMPORARILY on the 30a circuit. Just be sure to crank charge current down to 24a the moment you plug it in.

 

[dsgerbc]

Thanks guys. Sounds like b) is viable (wasn't sure about the 10 gauge wire) until I decide on the permanent solution and the plug may be useful later as well.

 

[davewill]

...
If indeed it does have two hots a neutral and a ground wire to that location, you can trivially swap it to a 14-30 and get the right Tesla adapter and then it will be perfectly safe in all conditions.

Some background reading for you that I wrote:
How Should I Charge My Tesla? – Article625.com

Welcome to Tesla ownership!

If you don't have a neutral wire, you could put in a 6-30 and use the following adapter:

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

@eprosenx will jump in to tell you he doesn't trust these third-party adapters, but the guy running the site has been serving the community a long time, and I think you'll be perfectly happy.

 

[dsgerbc]

If you don't have a neutral wire

I do. It's weird. Fused right at the 6-50 receptacle.

 

[davewill]

I do. It's weird. Fused right at the 6-50 receptacle.

Good for you. Of course, the white wire should never have been connected on a 6-50 at all, much less connected to the ground wire. Just as well you're fixing that stuff.

 

[eprosenx]

I do. It's weird. Fused right at the 6-50 receptacle.

Hah, that is funny. I guess that is one thing to do with the extra white wire (unused on a 6-50). That terminal on the receptacle though is likely not really rated for two wires (especially ones that might be different gauges - hard to tell).

Good for you. Of course, the white wire should never have been connected on a 6-50 at all, much less connected to the ground wire. Just as well you're fixing that stuff.

If that circuit goes back to a single panel which is the service entrance panel, then this is not dangerous at all (other than two wires under a single terminal not designed for it). At that main service entrance panel, ground and neutral are equivalent. Tying them together at the receptacle end just gives you more ampacity to shunt faults to, though this is probably quite frowned upon. I would have just capped off the white wire personally and left it hanging in the J-Box, but at the breaker end I would have landed it on the neutral bar.

 

[Rocky_H]

Huh--interesting options. First thoughts are: Are you ever going to use that interlocked connection for a generator? If not, I would want to just replace it with a regular outlet anyway. An L14-30 has all the wires to just easily switch it to a normal 14-30. But bonus that might be even better, is that you said it's 8 gauge separate wires in conduit. That is rated for a 50A circuit. So you legitimately could replace it with a 14-50 outlet.

For the other one, yes, 10 gauge Romex is rated for a 30A circuit. So I would replace that 6-50 outlet with a 6-30. I don't think Tesla makes a 6-30 adapter, so I would get one from EVSEAdapters.com

 

[Glamisduner]

With that plug, convert it to a 14-30. It's probably all you would ever need anyways. It needs to be fixed regardless of whether or not you get a tesla. Great temporary backup plug and fix. 14-30 is a handy adapter to have around.

If the other plug is 8awg and has 3wires plus a ground maybe you can convert it to a 14-50. Is it THHN or romex? If it's romex you might want to run a 40 amp breaker, you might have to check the temperature rating for the wire (It should be THHN in conduit). Or, if it's only 10 feet, maybe just replace the wire too. Personally if that outlet is still useful i'd convert the other one and just use that until you get your wall connector installed.

Huh--interesting options. First thoughts are: Are you ever going to use that interlocked connection for a generator? If not, I would want to just replace it with a regular outlet anyway. An L14-30 has all the wires to just easily switch it to a normal 14-30. But bonus that might be even better, is that you said it's 8 gauge separate wires in conduit. That is rated for a 50A circuit. So you legitimately could replace it with a 14-50 outlet.

For the other one, yes, 10 gauge Romex is rated for a 30A circuit. So I would replace that 6-50 outlet with a 6-30. I don't think Tesla makes a 6-30 adapter, so I would get one from EVSEAdapters.com

His pictures show all 4 wires so a 14-30 would work fine and tesla does sell that adapter.

 

[ewoodrick]

You didn't mention how much your commute is. It is quite possible that a simple 120V 15A plug is more than adequate.

 

[dsgerbc]

You didn't mention how much your commute is. It is quite possible that a simple 120V 15A plug is more than adequate.

Fair point. It might on some days. But I expect fairly regular weekend trips from the Detroit metro to Chicago and back, and will need place to prepare for those and to fill-up in reasonable time after.

 

[eprosenx]

It needs to be fixed regardless of whether or not you get a tesla.

The only code issue I see with the current install is two wires being shoved into the ground terminal on that receptacle (though from a practical standpoint I am sure it is fine since ground is not normally current carrying - would be hard for that to be an actual issue unless it was not making good contact) as long as the original load intended to be served by the 6-50 was not over 30a / 24a continuous. Code only says your receptacle must be rated AT LEAST at the rating of the circuit AND of the load to be served.

So if not for wanting to plug the Tesla into it, that receptacle as-is may be totally legit (they former owner may have had a welder with a 6-50 but that did not need more than 30a of current).

 

[mswlogo]

Option B, install 14-30. Don't forget to order the 14-30 Adapter from the store $35.

 

[Glamisduner]

The only code issue I see with the current install is two wires being shoved into the ground terminal on that receptacle (though from a practical standpoint I am sure it is fine since ground is not normally current carrying - would be hard for that to be an actual issue unless it was not making good contact) as long as the original load intended to be served by the 6-50 was not over 30a / 24a continuous. Code only says your receptacle must be rated AT LEAST at the rating of the circuit AND of the load to be served.

So if not for wanting to plug the Tesla into it, that receptacle as-is may be totally legit (they former owner may have had a welder with a 6-50 but that did not need more than 30a of current).

Yes that ground / neutral needs to be fixed.

My neutral and ground are on the same bar in my panel, but still you don't want them together like that.

It also makes sense to have they proper outlet though. Esp if the intent is to charge a Tesla.

 

[linkster]

I would switch out the 30a welder breaker for a 2-pole 20a and replace the the 6-50 receptacle with a commercial grade 6-20. This will provide ~15 mph charge rate and won’t require any manual reduction of charge rate in case you or the M3 forgets its geo-fenced reduced charge setting at that location. Obviously you will need to spend 35 bucks on a new adapter, which I believe is a useful adapter to own in one’s road tripping aresenal of useful items, and all is to code for long term, if needed. I currently charge an S and M3 with a 6-20.

btw, the folks over at EVSE adapters and @TonyWilliams have some slick reliable products that I have purchased over the years.

Good Luck!

 

[Federico]

Are you going to use that interlocked connection for a generator in the future? you can replace it with a 14-50 outlet and install a 40A breaker, remember you have 8 gauge ((the mobile charger use 32A, 40A braker should be fine).

 

[eprosenx]

I would switch out the 30a welder breaker for a 2-pole 20a and replace the the 6-50 receptacle with a commercial grade 6-20. This will provide ~15 mph charge rate and won’t require any manual reduction of charge rate in case you or the M3 forgets its geo-fenced reduced charge setting at that location. Obviously you will need to spend 35 bucks on a new adapter, which I believe is a useful adapter to own in one’s road tripping aresenal of useful items, and all is to code for long term, if needed. I currently charge an S and M3 with a 6-20.

btw, the folks over at EVSE adapters and @TonyWilliams have some slick reliable products that I have purchased over the years.

Good Luck!

Why would you do this? 10 gauge can handle a 30a circuit. He has four wires so he can install a 14-30. Downgrading it to a 6-20 makes zero sense.