HPWC Self-Installation

[bdaz]

Hello Everyone -

I'm going to install a HPWC shortly for my Model S that has the dual chargers.

If I'm going to the trouble of installation the conductor to my garage, I may as well wire up a 100A circuit. All the online guidance for self-installations is related to US wiring specs (THHN). The Canadian equivalent is T90.

Has anyone installed a 100A circuit? Is it worth it? Guidance on wiring selection? I believe I need to install a 100A switch within the garage as well.

Even if I do it myself I'm going to get an inspection certificate.. just wondering if anyone else on this board has gone through this too and can provide some guidance on supplies needed etc. (FYI - I'm well versed in wiring and requirements.. not a certified electrician though).

Thx!
b

 

[Ludatik]

You'll need to run 3 awg which is very challenging to work with. You'll need a disconnect within easy reach of the wall charger. Make sure you have enough headroom on your main panel I had to upgrade to 200A service. Your specific situation will present its own unique issues to work around so it's difficult to provide more advice.

 

[bdaz]

Thansk Ludatik -

Your comments are inline with my expectations. I have a 200A service (and a pony panel - so lots of room). I was planning on using T90 wire in conduit and a 100A disconnect directly above/nearby the charger.

 

[Rockster]

I installed dual wall chargers on a 100 amp circuit using 3 gauge wire. (I wanted to use 2 gauge but it’s too hard to work with, especially since I ran the wire into the units from the back, and the wall unit is very close to the panel.)

I used flexible metal conduit and split the 3 gauge with some multi-tap connectors.

 

[akidesir]

I did a self install with my uncle who is a electrician. I would say the install itself is easy if you have all the tools. Things I wouldn't of had would be the conduit lube to feed the three wires through the armoured conduit that we used. Also before my uncle arrived, I drilled holes from the main breaker and around my ceiling and into my garage which took away from most of the time consuming parts of the install.

 

[ksumnole]

Not quite the same, but I installed a 100A sub-panel to feed my two EVSEs. This is essentially the same thing you could do but substitute the 40A and 60A breakers in the sub-panel for one 100A breaker.

I personally ran a larger size aluminum wire instead of copper to the sub-panel since it saved me about $500 in wire cost. If I remember correctly, I used #1 AWG aluminum rated at 90 C.

 

[Ludatik]

Not quite the same, but I installed a 100A sub-panel to feed my two EVSEs. This is essentially the same thing you could do but substitute the 40A and 60A breakers in the sub-panel for one 100A breaker.

I personally ran a larger size aluminum wire instead of copper to the sub-panel since it saved me about $500 in wire cost. If I remember correctly, I used #1 AWG aluminum rated at 90 C.

View attachment 337681

I'm not an electrician but please note that the Tesla HPWC has this listed as one of the minimum requirements (page 9 of the installation manual): "Use only copper conductors". In my installation, I specifically requested they use copper wire only. Not sure of the impact of using a thicker gauge aluminum wire instead as you did.

 

[bdaz]

Thanks guys - this helps a lot.

 

[RAM_Eh]

I am an electrician. Please don't run aluminum as the terminations if not done right will cause hot spots and can cause a fire. Aluminum need more maintenance over the years as it is a softer metal and flows away from the pressure points. Needs to be tightened periodically .

if you are not versed in running conduit, use 3/3BX or Teck. If it is a dry environment you don't need the teck connectors, as they are expensive and regular BX connectors (L-18) will suffice. 1" emt 1hole clips will be needed to support the cable.

Consider installing a 100A panel in the garage (for future requirements) instead of a disconnect. The cost will be roughly the same and the breaker will be acceptable for disconnecting means. The panel should be at lease an 8 circuit panel to be useful in the future. GL

 

[RayOnTheRun]

Although I don't have a HPWC, I wired my setup to support it when I do buy one. My MS has Dual Chargers but for now I have a NEMA 14-50. What I did was make a service run to my garage using 2AWG Aluminum from my main 200A panel using a 100A breaker. It goes to a Siemens 100amp Indoor General Duty Safety Switch. From there, using 6AWG copper, I have the NEMA plug. In the future all I have to do is change the small copper run to 3AWG to support 80A.

I simplified the install and ran only about 3 feet of conduit in the garage and moved my car. This saved us a few hours a labor, being a Saturday afternoon project, my brother in-law and I banged it out quickly...with 5 kids running around the house. Yeah that's real life. I wouldn't have tried it alone without him and also calling the town inspector a few times just to make sure our install was up to code. Here is what it looks like now, imagine a fancy wall charger instead of a plug!

 

[fsch]

Has anyone installed a 100A circuit? Is it worth it?

I have a dual charger but decided to go for 40A at home anyway (on a 50A breaker) because we are rarely at home with a need to charge in ~4h hours. Either we are there for >8h (typically overnight) or we need to charge fast, in which case we go to the supercharger. It happened a few times on travel that we were happy to be able to charge at 80A but it did not happen at home so far.

So I let you consider your own habits and situation but it might not be "worth it" considering the extra costs and troubles (thick wire, contactor next to the HPWC, etc.)

 

[bdaz]

Good point. I figure if I'm going to the trouble to install this line, conduit, etc. I may as well future proof it as best I can.

 

[bdaz]

I am an electrician. Please don't run aluminum as the terminations if not done right will cause hot spots and can cause a fire. Aluminum need more maintenance over the years as it is a softer metal and flows away from the pressure points. Needs to be tightened periodically .

if you are not versed in running conduit, use 3/3BX or Teck. If it is a dry environment you don't need the teck connectors, as they are expensive and regular BX connectors (L-18) will suffice. 1" emt 1hole clips will be needed to support the cable.

Consider installing a 100A panel in the garage (for future requirements) instead of a disconnect. The cost will be roughly the same and the breaker will be acceptable for disconnecting means. The panel should be at lease an 8 circuit panel to be useful in the future. GL

Thanks - tremendously valuable information. I'm familiar with the disadvantages of Al vs. Cu as well (work in the industry) and will be going copper for those reasons/safety.

Definitely will be doing a 100A panel v. a disconnect - thanks for clarifying that it will qualify as a proper disconnect. Do you know what the max distance I can have it from the charger? Optimal placement for the panel would be the other side of the garage from where I want to install the charger, that would put it within direct line of site but 15ish feet away.

 

[Ludatik]

Good point. I figure if I'm going to the trouble to install this line, conduit, etc. I may as well future proof it as best I can.

This was my approach as well. If you’re doing the work anyway, you may as well put in infrastructure that is future proofed as much as possible. You’ll want the headroom when you bring home the Roadster.

 

[RAM_Eh]

Thanks - tremendously valuable information. I'm familiar with the disadvantages of Al vs. Cu as well (work in the industry) and will be going copper for those reasons/safety.

Definitely will be doing a 100A panel v. a disconnect - thanks for clarifying that it will qualify as a proper disconnect. Do you know what the max distance I can have it from the charger? Optimal placement for the panel would be the other side of the garage from where I want to install the charger, that would put it within direct line of site but 15ish feet away.

The code needs a disconnect within sight and 9M. You are good.

 

[bdaz]

The code needs a disconnect within sight and 9M. You are good.

Amazing. Thanks. I spoke to ESA inspector yesterday and he confirmed same.

Final question: for the ground, I can use bare copper bond wire correct?

 

[DMC-Orangeville]

Please don't run aluminum as the terminations if not done right will cause hot spots and can cause a fire. Aluminum need more maintenance over the years as it is a softer metal and flows away from the pressure points. Needs to be tightened periodically

While most of the points in his comment are absolutely true, I can tell you that You should NEVER re-tighten. I worked in applications at Alcan Cable (now General Cable). This is a common mis-conception that was published by Factory Mutual (FM) in the 80's, and retracted shortly afterwards.
Aluminum alloy cable had it's biggest issue when used with incorrect lugs. The lugs were designed for copper only, and couldn't expand to the degree needed when the conductor heated up under normal use. The "flow away" referred by @RAM_Eh is known as "creep". Almost all switches, designed for feeder use contain lugs that are now rated for both copper and aluminum conductors. The conductor should be brushed, have anti-oxidant paste applied and torqued to specification. It should never be re-torqued. The new lugs and alloys eliminate creep.

Of Note: the HPWC is copper lugs only.
Aluminum alloy could be run to the switch, but not to the HPWC

 

[Switzch]

I recently installed a HPWC by myself and had an inspector certify it. It's only a single installation - 60amp breaker - 6AWG cable. The inspector told me I don't need a disconnect if the charger is set to less than 60amp. In this case it was set to setting 9 (max 48) - he actually had me open the charger an check the setting. Have fun!

 

[RAM_Eh]

Amazing. Thanks. I spoke to ESA inspector yesterday and he confirmed same.

Final question: for the ground, I can use bare copper bond wire correct?

No if run in a conduit. You need to run green conductors if run in a conduit. Bare can only be run by itself.

 

[rhumbliner]

I'm not an electrician but please note that the Tesla HPWC has this listed as one of the minimum requirements (page 9 of the installation manual): "Use only copper conductors". In my installation, I specifically requested they use copper wire only. Not sure of the impact of using a thicker gauge aluminum wire instead as you did.

Note that @ksumnole said he ran aluminum from the main to the sub-panel. He didn’t say he ran aluminum to the WC.

I upgraded my main from 200-amp to 300-amp and then added a 100-amp sub-panel to my garage. I ran aluminum to the sub-panel and copper from the sub-panel to the WC. The 100-amp sub-panel gives me the option of adding a second WC someday. Also, since the run to the garage was a long one I used 1/0 awg aluminum just to have some extra headroom.