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HPWC to NEMA 14-50

smilepak

Active Member
May 11, 2015
1,739
532
SoCal, CA
Anyone connected their HPWC to a NEMA 14-50 outlet. Can you show me your wiring setup, some pictures of the connections and cables? I am interested in trying it out.

Thx
 

mknox

Well-Known Member
Aug 7, 2012
10,103
1,868
Toronto, ON
I have a NEMA 14-50 in the garage. I was thinking of buying a second UMC so I could leave one in the car, but a) the UMC has been discontinued for sale in Canada and b) the HPWC was only something like $100 more, so I bought a HPWC.

All I did was purchase a cord set intended for an electric range at my local Home Depot. It has a NEMA 14-50 plug on one end and bare wires on the other. I installed a cable strain relief fitting into the HPWC, ran the cable inside and hooked it up. I set the DIP switches to the position for a 50 amp circuit (40 amps delivered). Mounted the UMC to the wall near my outlet and plugged it in. Works like a champ.
 

jbcarioca

Well-Known Member
Feb 3, 2015
5,403
27,266
Mine is connected directly to a 40 amp circuit breaker with a metering device inline because I live in a condominium and must pay thevAssociation for my electricity. The Tesla connector, whether HPWC or just the connector without the HPWC logic, is a much nicer choice than is any NEMA or SAE solution, IMHO. My own experience is that I really do not need a higher power because my car sits in the garage for a long time, so I have no need for faster charging at home. It's always nice to have more, but why pay for something I will never need or even want? I admit it is a bit odd to think that way when the car is seriously over powered, but...:wink:
 

mknox

Well-Known Member
Aug 7, 2012
10,103
1,868
Toronto, ON
Thanks. Good to know they have the cable already made at Home Depot. Is it in the electrical section?

Here's an example. You can find them on Amazon or just about anywhere.

- - - Updated - - -

Wow, did not know that. Why did they discontinue it?

Not sure. As I say, I toyed with the idea of a second UMC but since the HPWC was only a bit more money, I decided to go that route. When I mentioned this at the Service Center when I picked up my HPWC, they said it was a good thing I'd made that decision because the UMC is no longer for sale, and they wouldn't have been able to get me one even if I wanted it.
 

ecarfan

Well-Known Member
Sep 21, 2013
19,276
13,947
West Vancouver, British Columbia
Anyone connected their HPWC to a NEMA 14-50 outlet. Can you show me your wiring setup, some pictures of the connections and cables? I am interested in trying it out.
Just curious: why do you want to convert an HPWC with a Model S/X connector to one with a NEMA 14-50 connector? Then to charge the car you have plug the UMC with the 14-50 adaptor into the HPWC cable with the 14-50R?

Do you want to do this simply to make the HPWC a more versatile power source?
the UMC has been discontinued for sale in Canada.
Do you mean that it is no longer possible in Canada to buy the UMC separately from the car? After all, a UMC comes with every Model S/X sold in Canada. Why wouldn't Tesla sell the UMC separately?

p.s. Now that near-production versions of the X have been seen on the streets in California, I somehow feel compelled to write "Model S/X" instead of just "Model S" when discussing items like the UMC. [emoji3]
 
Last edited:

mknox

Well-Known Member
Aug 7, 2012
10,103
1,868
Toronto, ON
Just curious: why do you want to convert an HPWC with a Model S/X connector to one with a NEMA 14-50 connector? Then to charge the car you have plug the UMC with the 14-50 adaptor into the HPWC cable with the 14-50R?

Do you want to do this simply to make the HPWC a more versatile power source?
Do you mean that it is no longer possible in Canada to buy the UMC separately from the car? After all, a UMC comes with every Model S/X sold in Canada. Why wouldn't Tesla sell the UMC separately?

p.s. Now that near-production versions of the X have been seen on the streets in California, I somehow feel compelled to write "Model S/X" instead of just "Model S" when discussing items like the UMC. [emoji3]

The idea is to install a NEMA 14-50 cord set on to the HPWC so that you can simply plug it in to a pre-existing NEMA 14-50 outlet, rather than hard-wiring it in. No change to the cable that goes to the car.
 

MorrisonHiker

S 100D 2021.4.18.2
Mar 8, 2015
9,833
9,197
Colorado
The idea is to install a NEMA 14-50 cord set on to the HPWC so that you can simply plug it in to a pre-existing NEMA 14-50 outlet, rather than hard-wiring it in. No change to the cable that goes to the car.

I think ecarfan might've been confused because you had a typo in your original post. You mentioned adding the cable to the HPWC but then said:
Mounted the UMC to the wall near my outlet and plugged it in. Works like a champ.

Shouldn't that be HPWC instead of UMC?
 

mknox

Well-Known Member
Aug 7, 2012
10,103
1,868
Toronto, ON
JDo you mean that it is no longer possible in Canada to buy the UMC separately from the car? After all, a UMC comes with every Model S/X sold in Canada. Why wouldn't Tesla sell the UMC separately?

That's what I was told, and I don't really know why. I do know Tesla in Canada can still get them for warranty replacements, because I've had a couple replaced that way myself. I understand you can still get them in the US, but even the Accessories Page says for customers outside the US to contact their nearest Service Center.
 

davidc18

Active Member
Apr 25, 2015
1,830
1,235
Ft. Lauderdale
+1 - exactly what I did as well.

I have a NEMA 14-50 in the garage. I was thinking of buying a second UMC so I could leave one in the car, but a) the UMC has been discontinued for sale in Canada and b) the HPWC was only something like $100 more, so I bought a HPWC.

All I did was purchase a cord set intended for an electric range at my local Home Depot. It has a NEMA 14-50 plug on one end and bare wires on the other. I installed a cable strain relief fitting into the HPWC, ran the cable inside and hooked it up. I set the DIP switches to the position for a 50 amp circuit (40 amps delivered). Mounted the UMC to the wall near my outlet and plugged it in. Works like a champ.
 

m6bigdog

Member
Mar 29, 2015
150
33
San Ramon, CA
Anyone connected their HPWC to a NEMA 14-50 outlet. Can you show me your wiring setup, some pictures of the connections and cables? I am interested in trying it out.

Thx

FWIW, the Tesla Charging Support Team will inform you that the only approved wiring method for the HPWC is permanent on a dedicated branch circuit.
While the HPWC Installation Guide does not specifically state that a flexible power cord is not allowed, it only includes guidance for a permanent/hardwired installation.

The HPWC is a UL listed device (UL 2594 Standard) and as such the installation must comply with the manufacture installation instruction or the UL Listing is void and the equipment is therefore not acceptable to the NEC.

Also, the NEC restricts the length of the flexible cord to 12 inches when allowed, however for the Tesla HPWC the flexible cord is not an approved wiring method as per Tesla.
 

mknox

Well-Known Member
Aug 7, 2012
10,103
1,868
Toronto, ON
FWIW, the Tesla Charging Support Team will inform you that the only approved wiring method for the HPWC is permanent on a dedicated branch circuit.
While the HPWC Installation Guide does not specifically state that a flexible power cord is not allowed, it only includes guidance for a permanent/hardwired installation.

The HPWC is a UL listed device (UL 2594 Standard) and as such the installation must comply with the manufacture installation instruction or the UL Listing is void and the equipment is therefore not acceptable to the NEC.

I believe since it is not specifically prohibited in the installation instructions, it is still in the grey area. They don't show every conceivable permanent wired scenario either. In fact, there are weasel words in the instructions that say:

8-31-2015 1-37-47 PM.jpg


So by saying that, they should never be installed outdoors.

Also, the NEC restricts the length of the flexible cord to 12 inches when allowed, however for the Tesla HPWC the flexible cord is not an approved wiring method as per Tesla.

I wonder why that doesn't apply to, say, electric ranges or electric clothes dryers?
 

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