Extension cords

Extension cords

Anyone have any thoughts about an extension cord for the NEMA 14-50 outlet? If I had a ten foot extension cord it would optimize where I could park in my garage. It looks like it's just a straight RV type outlet and an extension cord would work fine.

DonS | February 4, 2013

Warnings for high powered devices always warn to NOT use an extension cord. This is because it is all too easy to have undersized wire melt and/or cause a fire, burning down your car and garage. A properly made extension using SO or SJ cord with #8 AWG (or thicker #6 AWG) wire can do this safely, as long as the connection stays in a dry location.

TikiMan | February 4, 2013

You would be far better off hiring a professional electrician to just move the outlet closer to your car. You don't want to take chances with that kind of voltage.

Hills | February 4, 2013

This topic has been discussed extensively in the past. See
@nickjhowe and @jat.jaet seem to be not only experts but also handy.
I bought a 50 Amp extension cord for emergency only, but awaite delivery.

Really wish I can buy 10-30 and 15-30 adapters.

Sudre_ | February 4, 2013

They also do not have to move the outlet. They can add another outlet off the same one that is there now, only use one at a time.

jat | February 4, 2013

@Sudre_ - generally that will not pass code, as higher current devices must be the only thing on the breaker, and two outlets don't qualify even if you don't intend to ever use them at the same time.

As long as you get an RV extension cord that is rated for 50A (or 40A continuous), you should be fine.

Sudre_ | February 4, 2013

That's not true jat. You can have 14-50's as a general purpose outlets in a shop or a garage (pretty much anywhere) for portable welders, potable air compressors and the like.
I haven't looked to closely at the new electric car part of the code tho.

July10Models | February 4, 2013

You can't install a second 14-50 on the same circuit on less the breaker and the wiring is rated to support both in this case 100A. However, you can use the first outlet as a junction box to extend the wiring to a new termination. Just Install a blank cover over the junction box(existing outlet). It is never a good idea to use an extension cord as permanent installation even when it is rated for the job.

jat | February 4, 2013

@Sudre_ - you are correct: section 210.3 of the NEC says you can have multiple outlets on a circuit with up to a 50A breaker (local codes may vary) - I had remembered the limit being lower.

stevenmaifert | February 4, 2013
nickjhowe | February 4, 2013
howardc64 | October 25, 2013

Just installed a NEMA 15-40 outlet right next to the panel. Ran a 36' RV extension cord to the other side of the garage above the garage doors along the studs. Here is an interesting observation on where the weakest spot is in the circuit by feeling the temperature of various cord segments

After charging for awhile

A. 36' RV extension cable is nice and cool
B. Tesla's portable charger's cord on the end that connects to the NEMA 14-40 is thw warmest!
C. Tesla portable charger's cord that connects to the car is also warm but little coolder than B.

So B is the weakest link and came straight from Tesla. A is probably the strongest link.

Car charges at 40A, 240+V with no problem.

2-Star | October 26, 2013

I think it would be wonderful if Tesla would offer a standard extension cord (10-foot, 25-foot, 50-foot and maybe even 100-foot) that would attach to the adapter end of the UMC cord, with a second adapter socket at the other end. That way, you could use ANY adapter (NEMA 14-50, 5-15, 14-30, 10-30, et al) with this extension cord.

If it won't work at the adapter end of the UMC cord, maybe at the other end that plugs into the Tesla.

Any thoughts?

shop | October 26, 2013

Extension cords do have other problem including a trip hazard. If you trip over a cord and partially pull out a plug, that is going to generate some serious heat at the receptacle.