hackdroot
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Help installing NEMA 14-50 in garage

Sun Apr 16, 2017 1:35 pm

So in preparation for my new leaf, Im planning to use the Clipper Creek HCS-40P with the NEMA 14-50 plug to avoid having to install a disconnect in my garage. My main panel is outside and I plan on installing the NEMA outlet on the garage wall on the internal side of the wall.

In the attached pictures, the middle breaker on the right and it's associated wiring will be removed and replaced with a 40amp breaker and #8 wiring.

This seem like a real easy install since the wiring exits the wall right after it exits the main panel. it's only about 36 inches of conduit run horizontally from there, then the NEMA enclosure. I'm just not sure which is the 'right' way to transition the wiring from inside the finished wall to a conduit running on the outside of the finished wall to the NEMA outlet enclosure.

I would think romex from the breaker out of the main panel, into the wall, then through the drywall into a wall mounted junction box.

The second picture below is not mine, but demonstrates what I was thinking.

Image

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wwhitney
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Re: Help installing NEMA 14-50 in garage

Sun Apr 16, 2017 1:49 pm

Why do you need to run any exposed conduit? Cutting and patching the drywall is probably easier that dealing with a transition in wiring types. Plus you could recess the box containing the NEMA 14-50 receptacle.

BTW, if you use a NEMA 14-50 receptacle, I would say it is proper to run the neutral wire, even though the EVSE doesn't use it. NEMA 6-50 would avoid this issue.

Cheers, Wayne

hackdroot
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Re: Help installing NEMA 14-50 in garage

Sun Apr 16, 2017 1:59 pm

wwhitney wrote:Why do you need to run any exposed conduit? Cutting and patching the drywall is probably easier that dealing with a transition in wiring types. Plus you could recess the box containing the NEMA 14-50 receptacle.


Is it really though? It seems changing wiring type would be far quicker and easier than: cutting the drywall, drilling through the studs, mounting the box on the studs, replacing the drywall, patching/sanding the drywall, and then painting the walls back to finished color. My garage is finished and painted so I mentally walked through both options and it seemed easier to run a flex conduit outside the wall.

EDIT: Looking at it again, my horizontal run may include a 90deg turn to mount the station on the forward facing wall of the garage as well. I didn't realize how short the cord from the charging station really was to the NEMA. This may complicate burying the wires as well.

wwhitney wrote:BTW, if you use a NEMA 14-50 receptacle, I would say it is proper to run the neutral wire, even though the EVSE doesn't use it. NEMA 6-50 would avoid this issue.

Cheers, Wayne


You're correct and it appears that amazon has the same unit with the 6-50. I should just do the 50A breaker and #6 wiring instead though since it's recommended by the vendor in the product Q&A.
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wwhitney
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Re: Help installing NEMA 14-50 in garage

Sun Apr 16, 2017 2:25 pm

hackdroot wrote:My garage is finished and painted so I mentally walked through both options and it seemed easier to run a flex conduit outside the wall.

In that case, maybe so. I guess I assumed that if you were OK with exposed conduit, your garage probably wasn't finished and painted.

But now that you say your garage is finished and painted, I suggest considering concealing the wiring so it will look better. :-)

Either way will work.

hackdroot wrote:You're correct and it appears that amazon has the same unit with the 6-50. I should just do the 50A breaker and #6 wiring instead though since it's recommended by the vendor in the product Q&A.

I'm surprised that Clipper Creek would suggest a 50 amp breaker for a 32 amp EVSE. A 40 amp breaker would be fine with #8 NM/2 on a 6-50 receptacle.

BTW, for a 50 amp circuit, if you run conduit the whole way, you could pull individual #8 THHN conductors, which have an ampacity of 50 amps. NM is limited in its ampacity to a lower value, so it would require #6 NM to get to 50 amps. You could e.g. run some FMC in the wall and transition over to EMT for the exposed run.

To answer your original question, if you want to run NM in the wall and transition to EMT exposed on the garage wall, yes, use a junction box, come into the back of the box with the NM (use a cable clamp), and run EMT out the side of the box. If you want to splice the NM in the junction box to individual THHN conductors, then there's a required minimum volume for the box: 15 in^3 for 8/2 NM, 21 in^3 for 8/3 NM, 25 in^3 for 6/2 NM, and 35 in^3 for 6/3 NM. [Edit: those numbers assume that any cable clamps are outside of the box. If there's a cable clamp inside the box, add 3 in^3 for #8 NM and 5 in^3 for #6 NM.]

Stripping the sheathing off the NM cable for the length of the EMT conduit run is a bit of a gray area, as the individual conductors in the NM cable typically aren't marked with their type, even when the manufacturer says they are THHN or whatever. Otherwise it would be the most convenient option.

Running the cable with its sheath through your EMT is another option, although it's not clear how to clamp the cable when it reaches the box with the receptacle (although you could omit the clamp where the cable emerges from the wall). You'd also want to upsize your EMT so the fatter cable will go through it more easily.

Cheers, Wayne
Last edited by wwhitney on Sun Apr 16, 2017 2:41 pm, edited 3 times in total.

4CloverLeaf
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Re: Help installing NEMA 14-50 in garage

Sun Apr 16, 2017 2:26 pm

I am going to be wiring a NEMA 14-50 for my EVSE as well but plan to wire a 50A breaker and 6 gauge wire. I think at 40A you should be okay with 8 gauge but you probably want copper and not aluminum wire. You will need a total of four wires for the 14-50. One hot on each side, a neutral at the bottom and ground at the top. Normally you put a 14-50 receptacle in a box which you knock out a plug to feed the wire into. There will probably be a clamp as the wires enter to box to hold them in place so that they don't move from their connections on the 14-50 and you will want to ground the box as well. I am not a certified electrician but this should be pretty easy for the short run you have. I need to go 40 ft with 7 90 degree bends on the outside of my house and I am starting to think I should just hire an electrician to see if they could run it inside somehow. I think I am going to need 1 1/4 inch conduit going across the front of my house and above my front door with the 6/3 UF wire. Good luck with your project.

wwhitney
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Re: Help installing NEMA 14-50 in garage

Sun Apr 16, 2017 2:28 pm

hackdroot wrote: I didn't realize how short the cord from the charging station really was to the NEMA. This may complicate burying the wires as well.

Yeah, the input cord on an EVSE is limited to 12", as a big point of the EVSE is to provide ground fault protection. The cord, being upstream of the EVSE, won't be covered by the ground fault protection, so its length is limited.

Cheers, Wayne

wwhitney
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Re: Help installing NEMA 14-50 in garage

Sun Apr 16, 2017 2:39 pm

4CloverLeaf wrote:I think at 40A you should be okay with 8 gauge but you probably want copper and not aluminum wire.

I'm not sure if aluminum #8 wire is generally available, but if it is, for most wire types its ampacity will be 40A (75C ampacity, excludes NM cable).

4CloverLeaf wrote:I need to go 40 ft with 7 90 degree bends on the outside of my house

Conduit systems are limited to 360 degrees of bend between pull points, so if you do this in conduit you'll have to provide at least one pull point midway.

4CloverLeaf wrote:I think I am going to need 1 1/4 inch conduit going across the front of my house and above my front door with the 6/3 UF wire.

If most of the run is going to be exposed or buried 6/3 UF, then you could use a short run of conduit to protect the UF cable where exposed to damage. If you have a complete conduit system, then you'd be better off running individual THWN conductors.

Cheers, Wayne

hackdroot
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Re: Help installing NEMA 14-50 in garage

Sun Apr 16, 2017 4:50 pm

wwhitney wrote:
But now that you say your garage is finished and painted, I suggest considering concealing the wiring so it will look better. :-)

Either way will work.



To be honest, my garage has so much stuff, once the conduit is painted, it will barely be noticable. ;)


wwhitney wrote:I'm surprised that Clipper Creek would suggest a 50 amp breaker for a 32 amp EVSE. A 40 amp breaker would be fine with #8 NM/2 on a 6-50 receptacle.


Based on the statement below, I'm was guessing that there's some NEC requirements for the 6-50.


"Hello, For the plug in HCS-40P we recommend a 50A circuit going to the appropriate outlet (NEMA 6-50), this matches the installation requirement of the outlet you would be plugging the station into. For our hardwired HCS-40 we would recommend the station be installed onto a dedicated 40A circuit. Here is a link to the installation/ operations manual for the HCS-40 product line - http://www.clippercreek.com/store/wp-co ... Manual.pdf see less
By ClipperCreek SELLER on July 8, 2015"

Based on the following link though, the NEC code apparently dictates that you can use a 40 amp circuit on that 50A NEMA: https://diy.stackexchange.com/questions ... -a-circuit
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wwhitney
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Re: Help installing NEMA 14-50 in garage

Sun Apr 16, 2017 5:05 pm

hackdroot wrote:Based on the statement below, I'm was guessing that there's some NEC requirements for the 6-50.

There's no basis in the NEC for Clipper Creek's suggestion of using a 40 amp circuit for their hardwired HCS-40, but a 50 amp circuit for a receptacle for their HCS-40p. You could use a 40 amp circuit for the HCS-40p, that would fine, it's up to you. #8 Cu will be a little easier to work with than #6 Cu.

Cheers, Wayne

hackdroot
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Re: Help installing NEMA 14-50 in garage

Sun Apr 16, 2017 5:08 pm

wwhitney wrote:
hackdroot wrote:Based on the statement below, I'm was guessing that there's some NEC requirements for the 6-50.

There's no basis in the NEC for Clipper Creek's suggestion of using a 40 amp circuit for their hardwired HCS-40, but a 50 amp circuit for a receptacle for their HCS-40p. You could use a 40 amp circuit for the HCS-40p, that would fine, it's up to you. #8 Cu will be a little easier to work with than #6 Cu.

Cheers, Wayne


Then so it shall be. Thank you Wayne for your time and expertise. Happy Easter. :D
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