Wire for 40AMP Level 2 Electric Vehicle Charger

[Amphicar770]

Hi All,

Recently purchased a plug-in hybrid and want to put a level 2 charger in my residential garage.

I previously installed a sub-panel so have plenty of room for the breaker. Just want to make sure I get the right type of wire.

It is approximately 70' from panel to where I want to mount outlet for charger. Charger is a 40AMP JuiceBox. Plug is a NEMA 14-50. In my house, the Romex from panel runs along top of cement foundation wall. From there I can go through wall into garage. I am thinking I will just run the cable along the garage wall/floor/ceiling rather than behind the wall.


1. Any advantage to a 50amp breaker over 40amp. Instructions say either one.

2. Recommended wire type / size.

3. Does anything need to be run through conduit?

Here is link to the charger itself.
https://www.amazon.com/dp/B00UB9R4KO/?tag=atomicindus08-20

Thanks.

Mike

 

[grantw]

To get 40A of charging, you need a 50A breaker and 50A rated wiring. For my 14-50 outlet, I used #6 copper wire on a 50A breaker. Mainly because my outlet was ~18" off of the main panel via some EMT conduit.

The 40A continuous load is going to be 80% of the 50A breaker. 40A at 250VAC is a lot of power, and potential heat. Do not shortcut wire size/type or conduit where needed.

 

[75gmck25]

When I wired a receptacle for my kitchen range I found that 6/3 copper wire was readily available from the big box stores, and the current price is $163 for 75 feet at HD (its gone up quite a bit). You may get a better price online, but have to factor in the cost of shipping. Use the 6/3 wire with a 50 amp breaker, and you should be fine.

Bruce

 

[pgray007]

To get 40A of charging, you need a 50A breaker and 50A rated wiring. For my 14-50 outlet, I used #6 copper wire on a 50A breaker. Mainly because my outlet was ~18" off of the main panel via some EMT conduit.

The 40A continuous load is going to be 80% of the 50A breaker. 40A at 250VAC is a lot of power, and potential heat. Do not shortcut wire size/type or conduit where needed.

Second this motion and that’s exactly what I did and I believe is what code requires (80% of rated capacity for a continuous load).

I’m not 100% sure what you mean by “just laying down the wire” but if you’re not behind a wall I’d most definitely go through conduit.

If you search my threads I’ve got one somewhere with pic where I installed an OpenEVSE (similar to juice box and I ran a 50A breaker. It have the EVSE set to max out at 40A). Do note that the draw is also limited by the car’s internal charger. My BMW i3 will draw a max of about 7 kW/30-something amps. A hybrid may draw even less.


Sent from my iPhone using Tapatalk

 

[Amphicar770]

Thanks for the feedback. I actually wound up ordering the Siemens 32 Amp charger through Costco. Still planning to run the 6/3 Romex.

Am now thinking that I may want to mount the charger on an exterior wall. From a code / safety perspective let me know if this works.

70' Romex from panel in basement following same path as all the other Romex cables.

Come through the wall into garage. My understanding is that Romex should be protected but not run through Conduit. Thus, I will cut a trench in the garage wall sheetrock and run it behind there to point where I want to mount charger outside (unless a better suggestion).

The charger has a plug although I could replace that. On outside wall I was thinking I will mount one of these. GE Energy Industrial Solutions U054P Midwest Electric Outdoor Raintite Receptacle Enclosure, 120/240V, 50-Amp

Can Romex come directly through the exterior wall into the aforementioned receptacle box? I would then mount charger next to or above the receptacle and plug in. Alternatively, if acceptable, I can run the Romex through the wall and connect directly to back of charger without using the plug.

Appreciate the guidance.

Thanks.

 

[75gmck25]

Many folks seem to think you can't put Romex wire in conduit, but AFAIK there is no code that prohibits you from running Romex in conduit for protection. Just make sure the conduit is large enough to allow it to pull through easily. Use a long sweep 90 instead of a normal 90 if you have any bends.

Bruce

 

[Amphicar770]

Thanks. I decided that I do not want to deal with fishing cable behind the wall or cutting the sheetrock. Thus, I will run the Romex from panel to garage via basement. Then I will put a junction box and run armored 6/3 MC Cable along the interior garage wall to the outside termination enclosure.