Spare charging cord

[Rifleman]

I am still hoping for an inexpensive, non bulky level 1 charger to be available. This would be something great to keep in the car for that "oh-no" moment when you need to plug into someones 110 outlet for a few hours to get you to a level 2 charging station. If you ever need to charge away from home, odds are it is going to be one of these three ways :

1. A public j1772 charging station
2. A RV park with a 14-50 outlet
3. A 110 outlet.

It is my assumption that most trips that would use a 14-50 outlet would be planned in advance, and bringing the UMC along is no problem. When the spare EVSE would be needed is that unplanned event when you end up just a few miles short of getting to the next charger, and need to bum a 110 outlet from someone. This is when a compact an inexpensive level 1 evse would be perfect.

The Volt level 1 charger is only about $360 online, I wonder if, when combined with the j1772 adapter, would work on a model s. It's still pretty bulky, but the price point is actually just about right on it. If anyone has a model S nearby me, I would be happy to test my volt's level 1 on it, if you are brave enough to plug an unknown EVSE into your new car

[NeedToDrive]

Although I'm planning on getting the 40 kWh battery I will occasionally want to visit my brother in San Diego which is ~105 miles away. He has a standard 240V 'old' dryer outlet which looks like a Leviton NEMA 10-30:


Does anyone know if this will work with a standard 30A RV plug?:

The L slot looks big enough to allow a connection but I can't be sure. I can get a cheap 'dog-bone' adapter with this sort of plug that will allow me to connect to a spare charging cord with the standard NEMA 14-50 plug.

[qwk]

No, the RV plugs are only 120v. They are called TT-30.

[NeedToDrive]

Thanks... looks like I'll have to construct my own adapter (or switch out my brothers plug) .

[TXjak]

Thanks... looks like I'll have to construct my own adapter (or switch out my brothers plug) .

You could start with this 10-30 dryer cord and wire it to this 14-50 receptacle. Note that there is no separate ground, it was common to ground the dryer with the neutral wire before the 10-30 was obsoleted. I read somewhere that the Tesla doesn't use the ground wire anyway, so it may not matter.

P.S. I just got an email from a query I posed to Tesla a while ago: "You will receive the 14-50 adapter with your Mobile Connector. The 6-50 adapter can be purchased through a Tesla Service center. The 14-30 adapters are on backorder, and the 10-30 is a planned adapter that is not available yet." So you might want to wait a while and see, if you have the time.

[FlasherZ]

You could start with this 10-30 dryer cord and wire it to this 14-50 receptacle. Note that there is no separate ground, it was common to ground the dryer with the neutral wire before the 10-30 was obsoleted. I read somewhere that the Tesla doesn't use the ground wire anyway, so it may not matter.

No! no! no! You *must* have ground. If you have an existing 10-series receptacle, you may ground through the neutral for one appliance only on the circuit. The Tesla does not use the neutral pin on the 14-50P.

Attaching a 14-50R to a 10-30P is a really bad idea, because if the car is set to 40A, it will overload the 10-30 and the (likely) AWG 10 cabling in the wall. You'll be relying upon your circuit breakers as the only protection mechanism. Ensure you don't have an Federal-Pacific or Zinsco panel as well (whose breakers fail to trip in up to 80% of test cases).

If you insist upon making an adapter, mark it "TESLA CHARGING ONLY" and make sure it gets cut in half and thrown away with disposition of the car. NEVER plug a 120V/240V appliance (anything else requiring a 14-50) into the adapter cord because it could end up tying your electrical system to earth ground in multiple places (a safety hazard).

Finally, your best bet if you insist upon an adapter (when Tesla comes out with them) is to use a 10-30P to 14-30R adapter if you insist on making an adapter.

See the NEMA 10-30 thread and the NEMA 6-20 thread for more information.

The best solution, IMO, is to see whether a ground wire is present in the wall at the NEMA 10-30R and if so, replace it with a 14-30R. If not, run a separate ground wire back to the panel (per code it must be back to the panel, not to another device on another circuit), and swap for a 14-30R.

[TXjak]

No! no! no! You *must* have ground. If you have an existing 10-series receptacle, you may ground through the neutral for one appliance only on the circuit. The Tesla does not use the neutral pin on the 14-50P.

Attaching a 14-50R to a 10-30P is a really bad idea, because if the car is set to 40A, it will overload the 10-30 and the (likely) AWG 10 cabling in the wall. You'll be relying upon your circuit breakers as the only protection mechanism. Ensure you don't have an Federal-Pacific or Zinsco panel as well (whose breakers fail to trip in up to 80% of test cases).

If you insist upon making an adapter, mark it "TESLA CHARGING ONLY" and make sure it gets cut in half and thrown away with disposition of the car. NEVER plug a 120V/240V appliance (anything else requiring a 14-50) into the adapter cord because it could end up tying your electrical system to earth ground in multiple places (a safety hazard).

Finally, your best bet if you insist upon an adapter (when Tesla comes out with them) is to use a 10-30P to 14-30R adapter if you insist on making an adapter.

See the NEMA 10-30 thread and the NEMA 6-20 thread for more information.

The best solution, IMO, is to see whether a ground wire is present in the wall at the NEMA 10-30R and if so, replace it with a 14-30R. If not, run a separate ground wire back to the panel (per code it must be back to the panel, not to another device on another circuit), and swap for a 14-30R.

Good advice. I had assumed that you would keep the "dog bone" with the vehicle, but labeling it as such is a good idea.

[NeedToDrive]

You could start with this 10-30 dryer cord and wire it to this 14-50 receptacle. Note that there is no separate ground, it was common to ground the dryer with the neutral wire before the 10-30 was obsoleted. I read somewhere that the Tesla doesn't use the ground wire anyway, so it may not matter.

Funny, that was *exactly* what I was looking at doing - right down to the Amazon items.

Flasher, I understand that if I construct this set up I'd have to limit the current draw to 30A; I can do that from the car if necessary. Do you know how the UMC typically detects the type of circuit? Does one override detection whenever an adapter is used?

Keep in mind that this is not my house so changing the receptacle really isn't a desirable option - though I do like the idea. Surprising that a 14-30 wasn't there in the first place since the house was constructed in the late 90's. I don't like the idea of connecting the ground to neutral (that should only happen at the panel)... my thought was to leave it floating (unless the UMC complains about that). I'll certainly be keeping the adapter with the car and labeled.

I've done a lot of work on my own house and have ran into a lot of funky situations - including one case where neutral was connected to ground at a remote outlet. I can't forget the experience where I touched a conduit and 'felt' the electricity. Worse, I remember thinking "now that shouldn't happen" and grabbing it again to be sure. Fortunately, the load was such that it wasn't anything major - just a low level pulsating sensation. On my house it was a particularly bad situation given that the house was built in ~1965 and the ground wire is very small (~AWG 20?). BTW, thanks for the other links - very informative.

- - - Updated - - -

On second thought I think I'll rig a second 5-15 plug with suitable extension to my box (just long enough to reach a nearby 5-15 receptacle). I'll seal off the hot and neutral in the box and use ground pin for grounding the 14-50.

[FlasherZ]

Do you know how the UMC typically detects the type of circuit? Does one override detection whenever an adapter is used?

It doesn't detect the circuit at all -- based on the adapter, it chooses the highest available "continuous load" current available (80% of maximum). Put the 14-50 adapter on there, it will default to 40A. Put the 14-30 adapter on there, it will default to 24A.

Keep in mind that this is not my house so changing the receptacle really isn't a desirable option - though I do like the idea. Surprising that a 14-30 wasn't there in the first place since the house was constructed in the late 90's. I don't like the idea of connecting the ground to neutral (that should only happen at the panel)... my thought was to leave it floating (unless the UMC complains about that). I'll certainly be keeping the adapter with the car and labeled.

The MC won't complain about the neutral, but there is danger in leaving it floating if someone ever tries to use it for an RV, where two 120V appliances on opposite legs will create a 240V potential through them. So if you keep it marked and maintain the markings, you should be ok. Mark it "DO NOT USE FOR ANY OTHER PURPOSE" or something.

I've done a lot of work on my own house and have ran into a lot of funky situations - including one case where neutral was connected to ground at a remote outlet. I can't forget the experience where I touched a conduit and 'felt' the electricity. Worse, I remember thinking "now that shouldn't happen" and grabbing it again to be sure. Fortunately, the load was such that it wasn't anything major - just a low level pulsating sensation. On my house it was a particularly bad situation given that the house was built in ~1965 and the ground wire is very small (~AWG 20?). BTW, thanks for the other links - very informative.

Yes, I've been a part of a return path for a 120V load on an ungrounded appliance before. Don't touch the sink and the oven at the same time.

On second thought I think I'll rig a second 5-15 plug with suitable extension to my box (just long enough to reach a nearby 5-15 receptacle). I'll seal off the hot and neutral in the box and use ground pin for grounding the 14-50.

It should be noted that this isn't to code, but should work. The use of a #12 or #14 ground to sink a 50A current in case of a short is a concern of mine, but should be enough to trip the breaker. As a permanent install, you need a #8 ground.

[NeedToDrive]

FlasherZ, I just finished reading through the other two threads and I commend you on your contribution.

You had a good point there about the likelihood that my brothers 14-30 is a direct line to the panel. That makes connecting the ground and neutral together less of an issue. Of course you're right about the dangers of leaving the ground open. Connecting them is a option that, shall we say, I'm sensitive about. As you know, the problem with these kluges is that they frequently get out of the "lab' environment and to folks with less knowledge. Even good labeling frequently doesn't prevent dangerous usage. One reason I like the extension option (#12 would be my preference) is that it makes explicit the expectation both need to be plugged in.

BTW, I kind of guessed the UMC used the adapter to select current (how else could it know wire gauge!). It's a shame it selects 80% maximum. In my case I connected a 14-50 with #6 within 18" of the main panel to a 50A 2-pole breaker. The breaker is connected to a separate meter (SCE provides a better TOU rate with a second meter) I really should be able to get 50A no problem (assuming the UMC was properly rated).