L14-30 Garage Outlet

[PushinT]

Hey Everyone,

During inspection of a home that I am purchasing, I discovered this L14-30 outlet in the garage with seemingly no current use from the current owners. My question to the group is if anyone has experience using this type of outlet with the Gen 2 Tesla Wall Connecter charger using an adapter for this type out outlet for Level 2 Charging. My current townhome has a Nema 14-50 outlet that I use with the provided adapter that charges at 32A/250V. Would this type of outlet provide similar charging capabilities as my current setup? I obviously plan to have an electrician come out to test this outlet prior to plugging in, if at all possible.

My thought we be that this linked and pictured below adapter would plugin to my Gen 2 Tesla connecter and into the outlet, and charge as I'm used to?: L14-30 Twist-lock Adapter for Tesla Model S/X/3/Y Gen 2

 

[RayK]

At the very least, I'd change the outlet to something non-Leviton. There's been more than a handful of reports here that say Leviton is not robust enough for EV charging, although I think it's more towards the 50A outlets than 30A. If 30A charging is enough for your purposes (24A for the mobile connector), which it seems like from your current usage, then I would replace the outlet with a 14-30 (Hubbell or Bryant) and get the Tesla 14-30 NEMA adapter for your mobile connector. If you want to spend more money, then upgrade the wiring and breaker to 50A and put in a 14-50 so you can use your existing 14-50 NEMA adapter.

I guess it comes down to: is it worth spending the extra money to put in a 14-50 circuit, when it gets you just 8A of more charging current?

 

[Cosmacelf]

Yes that adapter and receptacle look fine. Assuming it was installed correctly, it would provide you with 24A charge rate which is fine for most people.

My guess is that it was originally installed as a generator inlet to feed power back into a panel. So do check to see where the 30A double pole breaker for that receptacle is.

 

[Braumin]

I would switch that receptacle to a Hubble NEMA 14-30. As @RayK said Leviton isn't well-known for reliability and there are many, many reports of their receptacles failing when they deal with the strain of max-amperage draw for 8-10 hours that EVs demand.

A 30A is plenty for charging, and I'll just again concur with RayK that the difference is only 8 amps over a 50A circuit so 24A vs 32A. Not worth the cost of changing the whole circuit even if you had room in the panel.

 

[RayK]

One other thing that I did not mention in my first post and a follow-up to a point that @Cosmacelf brought up...

When you have your electrician out to look at the breaker (to see if it was used as a generator feed), have him/her run a load analysis too. That will tell you have many amps you have to dedicate to EV charging. There may only be enough power to support a 30A load and that if you really wanted 50A, some other things are going to have to change.

My experience with twist-lock 240V plugs have been in electrical equipment used in semiconductor testing (memory testers, wafer probers, temperature forcing systems). Stuff that you don't want to accidentally pull out of the wall while you're using it. The previous homeowner may have had a shop with some equipment that falls under the same usage. Or, as Cosmacelf suggests, they may have had a generator for when those bad weather events that come through there happen. If so, then for sure a load analysis would be needed as you then cannot assume that 30A is even available.

 

[PushinT]

At the very least, I'd change the outlet to something non-Leviton. There's been more than a handful of reports here that say Leviton is not robust enough for EV charging, although I think it's more towards the 50A outlets than 30A. If 30A charging is enough for your purposes (24A for the mobile connector), which it seems like from your current usage, then I would replace the outlet with a 14-30 (Hubbell or Bryant) and get the Tesla 14-30 NEMA adapter for your mobile connector. If you want to spend more money, then upgrade the wiring and breaker to 50A and put in a 14-50 so you can use your existing 14-50 NEMA adapter.

I guess it comes down to: is it worth spending the extra money to put in a 14-50 circuit, when it gets you just 8A of more charging current?

One other thing that I did not mention in my first post and a follow-up to a point that @Cosmacelf brought up...

When you have your electrician out to look at the breaker (to see if it was used as a generator feed), have him/her run a load analysis too. That will tell you have many amps you have to dedicate to EV charging. There may only be enough power to support a 30A load and that if you really wanted 50A, some other things are going to have to change.

My experience with twist-lock 240V plugs have been in electrical equipment used in semiconductor testing (memory testers, wafer probers, temperature forcing systems). Stuff that you don't want to accidentally pull out of the wall while you're using it. The previous homeowner may have had a shop with some equipment that falls under the same usage. Or, as Cosmacelf suggests, they may have had a generator for when those bad weather events that come through there happen. If so, then for sure a load analysis would be needed as you then cannot assume that 30A is even available.

I do believe my inspector mentioned that the breaker was wired for 50A, but it of course sounds like something I should have an electrician confirm. I believe the wisest solution would be, if it were capable of 50A, to be to just have them replace this outlet with a NEMA 14-50 outlet? If I am understanding correctly.

 

[mongo]

My guess is that it was originally installed as a generator inlet to feed power back into a panel. So do check to see where the 30A double pole breaker for that receptacle is.

That would be scary since it's the wrong gender and would require a double plug cord to connect to a genset.
Previous owner may have had an RV or higher power tools?

 

[FastEddieB]

For some convoluted reasons, that’s what I use at our TN home, using the adapter mention in the OP.

Gives about 23 miles of range per hour, such that overnight always tops us off to our usual 80%. I know “piggybacking“ receptacles is not “kosher”, but it works for us - we just know not to raise or lower the hangar door while charging. So no need to derail the thread with cautions.

 

[mongo]

For some convoluted reasons, that’s what I use at our TN home, using the adapter mention in the OP.

Gives about 23 miles of range per hour, such that overnight always tops us off to our usual 80%. I know “piggybacking“ receptacles is not “kosher”, but it works for us - we just know not to raise or lower the hangar door while charging. So no need to derail the thread with cautions.

I'm guessing the flex originally fed the disconnect?
Because otherwise....

 

[FastEddieB]

Good catch. Yes, original receptacle installed so in a power failure I could raise the hangar door using our generator, unplugging from the receptacle and plugging into the L14-30R on the generator. Just happened to be very conveniently located for Tesla charging.

For a while just plugged into and unplugged from the single receptacle, though having a second one is a lot more convenient and avoids the wear from constantly plugging and unplugging.

 

[RayK]

I do believe my inspector mentioned that the breaker was wired for 50A, but it of course sounds like something I should have an electrician confirm. I believe the wisest solution would be, if it were capable of 50A, to be to just have them replace this outlet with a NEMA 14-50 outlet? If I am understanding correctly.

Lots of "ifs"....

If the circuit is a regular outlet (i.e., not for a generator input), if the circuit already has wiring and breaker rated for 50A (if it does, why was only a 30A outlet used?), if the electrician says a load analysis can support 50A, then yes, swapping in a quality (Hubbell/Bryant) 14-50 outlet should work and would probably be the least cost.

If the circuit only was wire rated for 30A, then you will have to upsize the wire gauge if you really want 50A. Have an electrician check everything out.

Another thing that should be mentioned is that I believe that a garage outlet needs to be protected by a GFCI breaker per current electrical code (I'm not an electrician but that's what I understand). That breaker alone can cost $100+ and may cause some false tripping when used with a mobile connector (or any other EVSE for that matter).

 

[davewill]

Lots of "ifs"....

If the circuit is a regular outlet (i.e., not for a generator input), if the circuit already has wiring and breaker rated for 50A (if it does, why was only a 30A outlet used?), if the electrician says a load analysis can support 50A, then yes, swapping in a quality (Hubbell/Bryant) 14-50 outlet should work and would probably be the least cost.

If the circuit only was wire rated for 30A, then you will have to upsize the wire gauge if you really want 50A. Have an electrician check everything out.

Another thing that should be mentioned is that I believe that a garage outlet needs to be protected by a GFCI breaker per current electrical code (I'm not an electrician but that's what I understand). That breaker alone can cost $100+ and may cause some false tripping when used with a mobile connector (or any other EVSE for that matter).

Yes, a new install of an EV circuit would require a GFCI breaker, but since this is not a new install, he should not have to go back and change it now.

 

[RayK]

Yes, a new install of an EV circuit would require a GFCI breaker, but since this is not a new install, he should not have to go back and change it now.

I'm not knowledgeable about NEC rules but if the OP could upgrade to a 50A circuit, meaning a new breaker and new suitable wires, does that still mean it's not a "new" install? If this like a home "addition" (or a remodel) as long as you leave one original wall standing?

 

[Watts_Up]

Before upgrating to 50 A, could you determine
- the wire gauge size,
- the type of wire (copper or aluminium, stranded or solid) and
- wire length between the circuit breaker and the receptacle plug.

Even if you don't make any change to the L14-30 I would check
if the wires connction to the receptacle plug are not corroded.
If so, I would cut the wire, like one inch if that possibe,
to have a clean connection.

Note: You should also check if your local power distribution
has a special EV rate, or off-peak hours rate.

 

[mswlogo]

I would just hardwire and skip the outlets.

30A 240V is plenty. You don’t need 50A.

 

[Watts_Up]

I would just hardwire and skip the outlets.

30A 240V is plenty. You don’t need 50A.

You are right, I have a NEMA 14-30 plug.
So 24 Amp under 240V gives 5.8kW or 23 kWh after 4 hours.

My off-peak starts at midnight until 3 pm the next day.
I often only charge just before the weekend and after the weekend.

With a NEMA 14-50 I would be limited to 32 Amp with the inboard Tesla charger.
So 32 Amp under 240 V gives 7.7kW or 23 kWh after 3 hours.

 

[mswlogo]

You are right, I have a NEMA 14-30 plug.
So 24 Amp under 240V gives 5.8kW or 23 kWh after 4 hours.

My off-peak starts at midnight until 3 pm the next day.
I often only charge just before the weekend and after the weekend.

With a NEMA 14-50 I would be limited to 32 Amp with the inboard Tesla charger.
So 32 Amp under 240 V gives 7.7kW or 23 kWh after 3 hours.

Yeah a short off peak window like yours would warrant going for the 50A. Assuming your car can consume that rate of course.

 

[Cosmacelf]

Yeah a short off peak window like yours would warrant going for the 50A. Assuming your car can consume that rate of course.

You misread. Off peak for him is 15 hours long, not short.

 

[PushinT]

Before upgrating to 50 A, could you determine
- the wire gauge size,
- the type of wire (copper or aluminium, stranded or solid) and
- wire length between the circuit breaker and the receptacle plug.

Even if you don't make any change to the L14-30 I would check
if the wires connction to the receptacle plug are not corroded.
If so, I would cut the wire, like one inch if that possibe,
to have a clean connection.

Note: You should also check if your local power distribution
has a special EV rate, or off-peak hours rate.

I did find that it was connected to a 50A breaker. I have an electrician scheduled to replace the LI-30 with a NEMA 14-50.

Other than checking the wire in various capacities, assuming that all checks out as acceptable, it should be as simple as installing the NEMA 14-50, connecting the mobile charger and charging at 32A moving forward?

 

[PushinT]

Lots of "ifs"....

If the circuit is a regular outlet (i.e., not for a generator input), if the circuit already has wiring and breaker rated for 50A (if it does, why was only a 30A outlet used?), if the electrician says a load analysis can support 50A, then yes, swapping in a quality (Hubbell/Bryant) 14-50 outlet should work and would probably be the least cost.

If the circuit only was wire rated for 30A, then you will have to upsize the wire gauge if you really want 50A. Have an electrician check everything out.

Another thing that should be mentioned is that I believe that a garage outlet needs to be protected by a GFCI breaker per current electrical code (I'm not an electrician but that's what I understand). That breaker alone can cost $100+ and may cause some false tripping when used with a mobile connector (or any other EVSE for that matter).

finally closed on house and it is indeed 50A breaker labeled "welding"