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NEMA 14-30 dryer outlet and Camco 14-50 extension

Hi everyone,

My house has a NEMA 14-30 dryer outlet and I bought a Camco NEMA 14-50 extension off Amazon and realized it doesn't fit because the Neutral prong is different.

From what I read on another thread I have heard it's possible to remove the Neutral prong on the extension cord as the Tesla UMC doesn't use the neutral. I just want to know if this is the best way to go?

Alternatively if anyone knows where I can get a decently priced adaptor in ON, Canada by next week I could just buy that. I get my car next Saturday so I'm trying to get this figured out ASAP
 

S'toon

Knows where his towel is
Apr 23, 2015
3,702
3,748
AB
Last edited by a moderator:
Thanks for posting that! One thing I should have stated is my NEMO 14-30 dryer plug looks like this, which is different that the RV 14-30 plug

I don't think that website has an adapter for this plug

- - - Updated - - -

***NEMA not NEMO sorry

- - - Updated - - -

The TT-30 in S'toon's post is only designed for 125V. They dryer is typically 240v which is much better for charging. I think you would prefer this adapter:

http://www.amazon.com/Conntek-14-30...1448676356&sr=8-2&keywords=nema+14-50+adapter

Thanks that looks like the one !

One other question, if I wanted could I just remove the neutral on my current extension cord?
 

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Wow thanks, that's exactly what I am going to do! I'll just buy the male/female outlets from Home Depot instead of Amazon so I can make this in time for my cars arrival next weekend! Thank you!

I pimp this link in any of these threads.. I've built three of these adapters for about $20 each with parts from Amazon.

http://cosmacelf.net/Home Made Adapters.pdf

Extremely helpful if you don't want to spend 3x as much on a prefab one.
 
Wow thanks, that's exactly what I am going to do! I'll just buy the male/female outlets from Home Depot instead of Amazon so I can make this in time for my cars arrival next weekend! Thank you!

Just remember, with a 14-30 to 14-50 adapter the car will think it's plugged into a 14-50 and try to draw 40 amps from your 30 amp dryer plug. You MUST remember to back the charging down to 24 amps or you could have fireworks for Christmas. :)
 

ecarfan

Well-Known Member
Moderator
The car uses the GPS location to remember the charge rate for each AC charging location.
That has been my experience and it does a good jub of remembering.
But what would happen if, for example, a charging location had two AC outlets of significantly different amperage and you used both of them. Would you have to manually adjust the charging amps to make sure you didn't overload the lower power circuit?
I have such a situation in my garage: an 80A HPWC which I use routinely and a 40A 14-50 which I installed as a backup and used once years ago just to test it. Don't recall now what the car did when I connected it to the 14-50. Should try it again...
 

Cottonwood

Roadster#433, Model S#S37
Feb 27, 2009
5,089
175
Colorado
That has been my experience and it does a good jub of remembering.
But what would happen if, for example, a charging location had two AC outlets of significantly different amperage and you used both of them. Would you have to manually adjust the charging amps to make sure you didn't overload the lower power circuit?
I have such a situation in my garage: an 80A HPWC which I use routinely and a 40A 14-50 which I installed as a backup and used once years ago just to test it. Don't recall now what the car did when I connected it to the 14-50. Should try it again...

That is actually pretty simple. The J1772 pilot duty cycle indicates maximum current available from the EVSE. The UMC (14-50) and HPWC are EVSE's that use J1772 signaling. The UMC with a 14-50 plug provides a 40 Amp pilot, and the HPWC with its DIP switches set to maximum (80A), provides an 80 Amp pilot. The car then uses the lower of the local location, and the pilot from the EVSE. If the location memory is 80 Amps, then with the HPWC, the lower of the car's location memory (80 Amps) and the pilot (80 Amps) is 80 Amps; with the UMC pilot (40 Amps), the lower is 40 Amps.
 
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Cottonwood

Roadster#433, Model S#S37
Feb 27, 2009
5,089
175
Colorado
I just cut the Neutral prong off my extension cord using a Dremel cutting wheel. If the current does not dial down by itself, then you will have to set it manually to about 25A for that dryer outlet.

To avoid tripping the breaker, you do not want to use more than 80% of the breaker rating. 80% of 30 Amps is 24 Amps.

I have encountered 14-30 dryer outlets feeding low power dryers that had 20 Amp breakers. I had to dial the current down to 16 Amps (80% of 20 Amps) to avoid tripping the breaker.
 

wraithnot

Model 3 VIN #2942 Model S VIN #5785
Dec 16, 2012
569
410
SF Bay Area
Just remember, with a 14-30 to 14-50 adapter the car will think it's plugged into a 14-50 and try to draw 40 amps from your 30 amp dryer plug. You MUST remember to back the charging down to 24 amps or you could have fireworks for Christmas. :)

I unintentially did this, but luckily the car detecting something wasn't right, dialed the max current down to 30 amps, and then shut down charging without tripping the breaker. I've been using a 10-30 to 14-50 adapter based on cosmacelf's instructions and a camco 14-50 extension cord for a while and everything had been working fine. But then I took the car in for service and somehow the 24 amp limit got reset back to 40 amps. Everything was fine after I set the current back down to 24 amps and restarted charging. But you should probably check the current setting after a service visit or a software update if you are using one of these adapters.
 

Canuck

Well-Known Member
Nov 30, 2013
6,125
5,779
South Surrey, BC
Hi everyone,

My house has a NEMA 14-30 dryer outlet and I bought a Camco NEMA 14-50 extension off Amazon and realized it doesn't fit because the Neutral prong is different.

From what I read on another thread I have heard it's possible to remove the Neutral prong on the extension cord as the Tesla UMC doesn't use the neutral. I just want to know if this is the best way to go?

Alternatively if anyone knows where I can get a decently priced adaptor in ON, Canada by next week I could just buy that. I get my car next Saturday so I'm trying to get this figured out ASAP

I bought a Camco extension cable too because I needed to charge from the dryer at my cabin before I installed a HPWC there. Then I realized the range also plugs in and I could get 40 amps when we didn't need to cook -- and I wanted one cable for both. I then learned that Camco cable has an extra wire that is not needed. It's bulky, heavy and unruly. So I researched here and made my own. I bought this wire:

6 3 SOOW So Cord 25 ft HD USA Portable Outdoor Indoor 600 V Flexible Wire Cable | eBay

And these ends:

Camco 55353 50 Amp Female Replacement Receptacle Free Shipping New | eBay

Camco 55255 RV 50 Amp Electrical Cord Male Replacement Plug End w Handle | eBay

I removed one pin from the male end of the Camco plug so it fits in both my dryer and stove outlets. Then I dialed down the amps in my car to 30 when using my dryer outlet.

But I am not recommending this anyone. I am just saying what I did, and what works for me. FlasherZ provides advice you should follow. I have no electrical experience at all. I followed this thread and made some changes to suit my needs:

How to build a lightweight 50A extension cord
 

FlasherZ

Sig Model S + Sig Model X + Model 3 Resv
Jun 21, 2012
7,028
1,025
Breakers don't trip immediately when you exceed their value - for example, you can draw 31A from a 30A breaker for a little while, and it might never trip. However, I can tell you that drawing a 30A continuous load through a 30A rated receptacle for more than a short period of time will likely melt the receptacle - there's not much headroom.

Also, while the car does remember location via GPS, there are times that it's not perfect. For example, my Model S has recognized my home as two different addresses (with two different charging currents). In addition, after upgrading software I have seen the current level reset to 80A again.

It's a bad idea to connect a Tesla via a NEMA 14-50 adapter to a 30A circuit. If closely monitored, it's likely going to be okay, but you shouldn't make it a regular habit if possible. If you do, I recommend that you build a 14-30 to 10-30 adapter cable and use it with Tesla's 10-30 adapter to prevent overcurrent (or see if you can find a Tesla 14-30 adapter still hanging around).
 

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