Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Electricians: Code question on a THHN #6 bend for a rear HPWC hookup?

Mike Hawk

Member
Jan 8, 2019
55
97
Tulsa Oklahoma
I have a HPWC gathering dust (gifted to me from the guy who's referral I used). Figured I minus whale put it to good use. Here's my conundrum. My OCD won't allow conduit to be visible in my garage, which would allow a top entry into the HPWC. I'll be feeding the #6 from the attic thru the header and down thru the assumed 2x4 studs/drywall. I'm okay with having to bust up the drywall to be able to attach the 1" conduit to studs.

My concern is the turn in the #6 from vertical to horizontal to go to the rear of the HPWC. Can I terminate the conduit in a junction box that rests behind the drywall and then just try the gentlest of bends to get the #6 L1/L2 terminations on the HPWC?

I need to figure out what permits/inspections will be required if I wanna follow the letter of the law. Granted, I'm not an electrician but this isn't rocket science and I'm really not looking forward to paying the Tesla Tax. Especially for my case which would require a 'hidden' run. I doubt many electricians would wanna deal with someone as picky as me. Guess I could do all the work, leave the drywall unattached and see what an electrician would cost to double check my work. Hmm
 

Rocky_H

Well-Known Member
Feb 19, 2015
5,964
6,885
Boise, ID
Figured I minus whale put it to good use
I doubt that's an Oklahoma good ole boy saying, so I'm going to guess voice to text. ;) That is a good idea to remove the whale, though, because it wouldn't fit behind the drywall.

Can I terminate the conduit in a junction box that rests behind the drywall and then just try the gentlest of bends to get the #6 L1/L2 terminations on the HPWC?
I think that is a pretty normal way to do that. You end the conduit in a box behind the wall connector, and then you have just the wires to run inside the unit.

Guess I could do all the work, leave the drywall unattached and see what an electrician would cost to double check my work.
That's the wrong type of employee. An electrician does stuff and then has an inspector check it. You want to do the stuff yourself and then you would have an inspector check it.
 
  • Like
Reactions: jjrandorin

Tessaract

Member
Aug 12, 2019
334
321
Ottawa
I have a HPWC gathering dust (gifted to me from the guy who's referral I used). Figured I minus whale put it to good use. Here's my conundrum. My OCD won't allow conduit to be visible in my garage, which would allow a top entry into the HPWC. I'll be feeding the #6 from the attic thru the header and down thru the assumed 2x4 studs/drywall. I'm okay with having to bust up the drywall to be able to attach the 1" conduit to studs.

My concern is the turn in the #6 from vertical to horizontal to go to the rear of the HPWC. Can I terminate the conduit in a junction box that rests behind the drywall and then just try the gentlest of bends to get the #6 L1/L2 terminations on the HPWC?
If you really want/need to use conduit, then a standard way to implement a right angle bend would be to use an LB fitting. However, this might not be allowed if the fitting cover is inaccessible. Also, it strikes me that if you're running the conductors/cable/conduit inside a wall, you could also use NMD-90 rather than conduit, given the inside of a wall is a protected location and NMD-90 would be code legal (at least here in Ontario).
 

Puddles

Member
Jun 2, 2017
728
844
Fresno, CA
Forgive me if I’m mis-reading but if you intend to put a box at the HPWC you do not want to conceal it behind drywall. Bring it up flush to the wall surface. As mentioned, if you’re running behind drywall I don’t think you need conduit, but a metal clad cable is mighty convenient if you’re running in & out of concealed areas.
 

Mike Hawk

Member
Jan 8, 2019
55
97
Tulsa Oklahoma
IIRC conduit is needed for multi conductor THHN #6 to be to code. I'd run romex but romex wouldn't allow me to do the full 48a w/o being crazy expensive and beefy. THHN #6 seems to be a nice compromise $ wise to be up to code to go into a 60a breaker. Tessaract, I'm not finding NMD-90 on eBay unfortunately.

The terminal box will be flush with the wall, it won't be behind the drywall. Visually all I want to see is the HPWC resting on the drywall, basically how all the Tesla.com product/promo shots look. Very minimalist.
 

kkillebrew

Banned
Jun 23, 2019
401
123
austin, tx
The most minimalist look is to put the #6 in the wall and mount the HPWC flush without using the exterior conduit "Plinth" or standoff that comes with the charger. Option B. Put a hole in your drywall and fish it through, then without bending it much at all you can connect it straight to the HPWC. Have the mounting bracket installed first against a stud on one side and drywall anchors on the other. Once connected (get it tight!) you can just lift the HPWC to the wall and screw it in place.
 

Rockster

Active Member
Oct 22, 2013
3,010
4,612
McKinney, TX
I ran #3 in the wall with the HPWC mounted flush. Bending the #3 to connect to the terminal in the HPWC was a royal pain but the finished product looks nice.

Wall chargers_wall open.jpg


Wall Chargers_finished.jpg
 
  • Like
Reactions: Puddles

SilverSp33d3r

No Longer Silver
May 23, 2018
525
370
LA
064CC309-45A9-4A3F-BAB9-E374DAA3E1B5.jpeg
Does the HPWC still come with the rear entry junction box? If it does, it comes pre-loaded with high stranded cables that are extremely flexible, plus a termination block for you to attach the #6’s. You just have the wall connector out 3” further from the wall.
 

eprosenx

Active Member
May 30, 2018
2,065
2,483
Beaverton, OR
I too love the clean looks.

Cleanest is the Wall Connector without the top entry standoff and with power coming in the rear.

You only need 3/4in conduit for #6 AWG.

I don’t know of any code compliant bends you could do in the Sheetrock since you would need access to them. Unless your wall was crazy deep and you could just bend EMT.

You could also do “flex” but I doubt it is bendable enough either and you would need to then convert it to something else if the run was more than a very short distance.

I would look heavily into MC cable. May be perfect for this. Can be used at 75C rating so you get the full 48 amps. Might be bendable enough to come direct into the back of the wall connector in the wall.

Good luck and please let us know what you do!
 

Tessaract

Member
Aug 12, 2019
334
321
Ottawa
IIRC conduit is needed for multi conductor THHN #6 to be to code. I'd run romex but romex wouldn't allow me to do the full 48a w/o being crazy expensive and beefy. THHN #6 seems to be a nice compromise $ wise to be up to code to go into a 60a breaker. Tessaract, I'm not finding NMD-90 on eBay unfortunately.

The terminal box will be flush with the wall, it won't be behind the drywall. Visually all I want to see is the HPWC resting on the drywall, basically how all the Tesla.com product/promo shots look. Very minimalist.
NMD90 is the electrical code term for what is popularly called Romex in the USA.

In Canada, the allowable ampacities are a little higher than those the NEC permits in the USA, probably because the ambient temperature maximums are lower in the "frozen north". So 6AWG Romex is suitable for a 60A circuit in Canada, where it is not in the USA. Unfortunately, now that I notice you're in Oklahoma, you may be stuck with 3AWG Romex as your option for a 60A circuit, which is significantly more difficult to handle.
 

Mike Hawk

Member
Jan 8, 2019
55
97
Tulsa Oklahoma
NMD90 is the electrical code term for what is popularly called Romex in the USA.

In Canada, the allowable ampacities are a little higher than those the NEC permits in the USA, probably because the ambient temperature maximums are lower in the "frozen north". So 6AWG Romex is suitable for a 60A circuit in Canada, where it is not in the USA. Unfortunately, now that I notice you're in Oklahoma, you may be stuck with 3AWG Romex as your option for a 60A circuit, which is significantly more difficult to handle.

Ah. Yup. Hence the THNN #6. Looks like the best wire to work with for my situation.
 

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top