How does the HPWC get wired?

How does the HPWC get wired?

If you don't have SolarCity do your wiring installation, what do you tell an electrician about how the HPWC gets wired? Does anyone know if it's hard-wired in, vs does it require a specific NEMA plug? The PDF on the charging page only says what amperage has to be supported. It says nothing about the physical details of the connection. This is in contrast to the description on the mobile connector page, which spells out that a NEMA 14-50 plug is recommended for home.

pilotSteve | August 16, 2012

@michaelwm - its hard wired to a box your electrician will install. To make full use of HPWC you need a 100A/240V breaker in your box, and very heavy wires. The pdf you mention is what you need to show to your electrician in order for them to quote your install.

Any qualified electrical contractor can do it.

BYT | August 16, 2012

Can someone please post a link to the PDF if it can be found online? I'm working on getting quotes but have no idea what to show an electrician.

BYT | August 16, 2012

Thanks Jerry!

cerjor | August 23, 2012

I just finished wiring my NEMA 14-50 in the carport. Easy conceptual job. Only took me three days. That #6 wire is really stiff. Here's my question. The outlet is about 5 feet from where the car will be. I plan to wrap about 15 feet of the cable in a tight coil and hang it near the outlet. That would leave 5 feet to reach the car. Will the coiled wire present a problem?

RobertMontreal | August 24, 2012


First of all, the coil shouldn't be a problem. We see pictures of the charging cable coiled all the time, and there's only current running through it when you are actually charging.

But I have a question for you. You mentioned the install took "only" three days. That sounds like a long time. Was it because you had to run the #6 wire from your electrical panel which was far away? Is that what took so long?


FlasherZ | August 24, 2012

I would imagine the coiled cord won't be a problem when the cord is stored, but you don't want to leave it coiled while charging, IMO...

stevenmaifert | August 24, 2012

Definitely do not want to leave it coiled while charging. You run the risk of inductive transient currents being generated: I don't think we know yet how the Model S charging software will respond to transients on the charging cable. Best not to experiment :)

pilotSteve | August 24, 2012

@cerjor - I'm a bit confused by your post. You said your NEMA 14-50 was installed [I thought this thread was about the HPWC which is hard-wired not NEMA 14-59 socket], then you ask about "coiling 15 feet of the cable".

So either:
(a) your are not using the HPWC but rather plugging the included Mobile Connector (not sure how long that cord is but I doubt it has 15' that needs to be coiled) -or-

(b) you have the HPWC hardwired (what amperage breaker? Is it 50A or 100A?) and you are talking about coiling the HPWC's cord. It will be interesting to see what Tesla says when the user manual is published. Might or might not be an issue to leave the unused portion coiled like the pictures on the web site.

Brian H | August 24, 2012

I wot it wuz irony, combining "conceptually easy" and "only 3 days". A wry reflection on the difference between drawing and doing a wiring job.

cerjor | August 24, 2012

RobInMtl: Well, parts of three days. I started at the plug and worked my way back to the breaker box. Wiring the plug was difficult because of the box that I was putting it in. The box was relatively small and the heavy wire had to be bent. The cable went into the attic above the car port so I had to remove a bunch of shelves which were blocking the access to that attic. The next problem was running the cable through two narrow spaces that connected the car port to the house (with breakers). That was all but impossible until my neighbor helped. Finally dropping the cable down from the house attice into the breaker box took a bunch of time. Once the cable was into the box, another half an hour finished the job.

pilotSteve: Sorry if I asked this in the wrong thread. I am doing the 14-50, not the HPWC.

jbunn | August 25, 2012


Get a plastic garden hose caddy from the hardware store. (The kind you loop 50 feet of garden hose around.) You'll have two, perhaps three loops if you mount it 4 feet off the floor and the loops hang down to a foot off the floor. Won't make a great inductor.

$3.97 at Home Depot. Any color you want as long as it's Dolphin Grey. Model # CPLHH15000
Store SKU # 296368

digitaltim | August 30, 2012

I think you'll find lots of options on an RV supply site:

DrJ | August 30, 2012

They haven't shown the back of the HPWC yet in order to know how it's going to be wired. My electrician ran a large conduit from my box to the spot in the garage where the HPWC is going to reside. He ran through the conduit 6 ga wire and using that installed a separate 14-50 plug and circuit just adjacent to where the HPWC will be installed. We did this based on Tesla's recommendation that you have a back-up 14-50 plug "just in case" you don't get your HPWC with or before your car. When the HPWC arrive he will then wire it using 2 ga wire thru a 100A breaker, but we'll wait until it arrives because Tesla hasn't been forthcoming on how to set it up. When I asked, I was told, "wire a 14-50, and we'll let you know whenever the HPWC are available" which I assume means they aren't available yet and therefore they can't tell you how to wire it.

jbunn | August 30, 2012

In order to do the rough-in wiring, all the electrician needs to know regarding the wire and breaker is voltage, ampacity, and distance from the box. Generaly unless it's in a detached building or a long run, distance isn't a factor. For example, he's going to choose the box size based on a formula of cubic inches in the box and the number and size of the conductors. Instructions for the HPC will only say "see local codes". He or she will also need to know where you want it located.

Installing in the HPC is finish electrical, and can be done seperatly.

Dr. Bob Reinke | September 1, 2012

When I asked to buy the HPWC in advance of delivery of my Model S Signature Performance, I was told that I couldn't buy it in advance, it would be delivered by the delivery team with the car. So much for having everything read on arrival.

jerry3 | September 1, 2012

I believe that's because they don't have them ready to ship yet. Once they have real production, that should change.

Chuck Lusin | September 1, 2012

digitaltim - Don't forget - Do NOT use an extension cord with the mobile connector. This is right from the Tesla PDF.

Check the last bullet item: