EV charging outlet boxes

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Electric Solutions

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Electrician
Hello, I’m new here and although I’ve been doing electrical work for quite a while, I’ve never installed an outlet for an electric vehicle before and just wanted to pick brains to all you experts that do it all the time.
So my customer wants one installed. Load calc says everything is kosher for an 14-50 outlet to be installed. Looking at box fill, it looks like I need a minimum of 42.5 cu in box to make this work because the device has to be counted twice. Am I reading that code correctly? If so, that only leaves a surface mounted 4 11/16 x 2 1/8” box with a RS cover as my only option. Or am I missing something? Thanks for any insight you can give.
Tony
 
Electric Solutions said:
Hello, I’m new here and although I’ve been doing electrical work for quite a while, I’ve never installed an outlet for an electric vehicle before and just wanted to pick brains to all you experts that do it all the time.
So my customer wants one installed. Load calc says everything is kosher for an 14-50 outlet to be installed. Looking at box fill, it looks like I need a minimum of 42.5 cu in box to make this work because the device has to be counted twice. Am I reading that code correctly? If so, that only leaves a surface mounted 4 11/16 x 2 1/8” box with a RS cover as my only option. Or am I missing something? Thanks for any insight you can give.
Tony
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What size and type of conductor are you using?

#6 NM cable is only 17.5 cu.in (5x3 + 2.5)
Device adds 10 more (5x2)
Clamp adds 5 more

That only comes to 32.5

Where are you getting 42.5 ?
 
James L said:
What size and type of conductor are you using?

#6 NM cable is only 17.5 cu.in (5x3 + 2.5)
Device adds 10 more (5x2)
Clamp adds 5 more

That only comes to 32.5

Where are you getting 42.5 ?
Click to expand...
Doesn't a 14-50 take a 2 gang box thus 5 x 4 ??
 
Thanks for the replies fellas. I did make a math mistake. Appreciate the heads up. Would you guys trust a cut in box with the plastic wings to secure the device well enough to allow the user to plug-in and unplug the cord over time? He says he won’t, but I can’t count on that.
 
James L said:
Ground is #10

The device counts as two conductors, not two conductors per gang....right?
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Wasn't my point.. I believe you calculated the device as 2 x 5 =10, but a 14-50 , I believe takes a two gang box and per 314.16:
A device or utilization equipment wider than a single 50 mm (2 in.) device box as described in Table 314.16(A) shall have double volume allowances provided for each gang required for mounting
 
Electric Solutions said:
Thanks for the replies fellas. I did make a math mistake. Appreciate the heads up. Would you guys trust a cut in box with the plastic wings to secure the device well enough to allow the user to plug-in and unplug the cord over time? He says he won’t, but I can’t count on that.
Click to expand...
I just cut in a box last week for a 14-50. I would not use an old work box. I would carefully locate a stud and use a 4 sq with extension ring or a two gang masonry box and screw it to the side of the stud. If you are careful, the plate will cover it. Or these are pretty roomy too.....

SLIDERBOX® Adjustable Wall Box Assemblies | Allied Moulded Products

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The one I did was actually fed with 4-3 AL MC cable, so I wanted as much room as possible. It was a 2x4 wall, and we didnt want to get into any patching, so I couldn't go up to a 4/11 box so there was no way to make it code compliant for fill, but I used a 4 sq deep plus extension ring plus a 1/4" mudring. That was the most I could get. I put the connector on the Mc and stuffed it up in the wall and got it to rest right where the KO was. Put the box in, side screwed it to the stud and then reached up with needle nose and pulled the cable into the box. It will certainly be easier with NM and #6.
 
Well, got the word from head electrical inspector for my city. The 14-50 outlet has to be counted 4 times because it is a double yoked outlet. So the grand total is 42.5 cu/in. Wanted to pass that along to help clear up any future questions guys might have in the future.
Thanks,
Tony
 
Interesting, because it will fit in a single gang box, as the yoke and width will allow it, but it would be a heck of a deep box for wire fill! So I would say he is incorrect in calling it as a double device for fill.
 
Electric Solutions said:
Well, got the word from head electrical inspector for my city. The 14-50 outlet has to be counted 4 times because it is a double yoked outlet. So the grand total is 42.5 cu/in. Wanted to pass that along to help clear up any future questions guys might have in the future.
Thanks,
Tony
Click to expand...
Kinda like in Post #8 & #12 ?? :) :)
 
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