Adding 240V Receptacle in Garage - Need Some Opinions

[KPtexan05]

I'm sure there are a couple ways of doing this, but wanted to get some thoughts on it if possible.

I've got an N3R main panel on the outside of my house (no main breaker which pisses me off, but here we are), and I'd like to install a 240V 14-50 receptacle on the other side of that wall which is inside the garage. This would be mainly for running a welder/shop tools and occasional visitor to plug in an EV. Two options I've been thinking about are:

1. Try to run 6awg UF or SER cable from a new 50A breaker in the main panel through the existing hole which runs into the wall cavity, and then right into an old work box for the receptacle in the garage. This seems the most straight forward and best looking option, but I'm not sure if I could fit another cable through that hole in the panel or if that hole even opens up as soon as it gets in the wall cavity. Does it have an elbow that runs those cables vertically into the attic or is it open right after it gets in the wall? What is typical here?
2. Drop a short piece of pvc conduit from a bottom knockout in my main panel, into an SLB, and then core a new hole in the brick wall for a short piece of conduit to enter the wall cavity. I think code allows for SER cable in this case as long as the conduit just enters the wall and doesn't go all the way to another box?

One thing of note is that I plan on eventually having an electrician swap out that main panel with a Square D QO main breaker unit with a few more spaces. It will also allow me to put an interlock for a 30A generator inlet somewhere below the panel. Maybe instead of using the SLB mentioned above, it would be smarter to run a conduit down to a larger J-box which would allow for the future installation of that generator inlet as well? Could wiring exit the back of that J-box to go into the wall for my 240V receptacle in the garage, and then eventually have another piece of conduit come off the side for the gen inlet?

I appreciate the help!

 

[Innovate1]

I would be doing the main panel swap first. Whatever you do with panel is likely not to line up with holes in the new panel and other such stuff. Why do the wiring to the stuff you add twice?

 

[mike93lx]

SER is fine in conduit, it just can't be underground.

 

[sparky 1971]

You can see if the existing cables go through the other side of the wall by measuring it out and then looking inside but I bet they go every which way as soon as they go inside. And I doubt you'd get another cable all the way through anyway. Just about anything else you do will be pretty much screwing yourself at the time of the panel change, especially since you want to change brands. The knockouts aren't going to line up. Add the receptacle and change the panel at the same time.

 

[theoldwizard1]

SER is fine in conduit, it just can't be underground.

If you have conduit, individual wires may be cheaper.

 

[KPtexan05]

I would be doing the main panel swap first. Whatever you do with panel is likely not to line up with holes in the new panel and other such stuff. Why do the wiring to the stuff you add twice?

Yeah, I agree it would be ideal to do the new panel swap first. It's just that I pretty much need the receptacle right now, and I could see the new panel not getting installed for another year or two. I pulled the dimensional drawings of the existing Eaton BR1224L125R and the planned QO120M200PRB and, while the knockout locations would be pretty close, they might just be far enough off to make it a problem. Guess I need to do some planning on this and try to speed up the new panel installation.

 

[KPtexan05]

SER is fine in conduit, it just can't be underground.

Yeah I thought I read somewhere it can be in conduit sleeve to protect it but shouldn't be in an end to end run of conduit. You're right, looks like it's OK, which would make more sense to me.

If you have conduit, individual wires may be cheaper.

True, I'd much rather deal with THHN or something here, but was thinking a conduit run all the way from the panel to the wall box may not be possible.

 

[Jim greengo]

I'd go with option 2 myself,more options of where you can install the outlet that way.

 

[mike93lx]

Yeah I thought I read somewhere it can be in conduit sleeve to protect it but shouldn't be in an end to end run of conduit. You're right, looks like it's OK, which would make more sense to me.

Pretty common internet myth.

If you are running conduit end to end, a jacketed assembly is a terrible choice anyway, though. Thwn/xhhw will be much easier.

 

[75gmck25]

I was right to assume you must be in Texas. When my house was built in San Antonio they had to install the electrical so that the A/C units could be shut off from outside the house, without going inside the garage to the real "main" panel with all the house 120 volt breakers. I think mine may have also had the oven and water heater 240 volt circuits on that outside panel. Always thought it was a little weird, but I had no issues.

I don't know what other local code requirements apply to a setup like this where you wire through an exterior panel for all the circuits. If you have to go through all the trouble to fit in a bigger panel you may want to add a 240 volt breaker that serves a new sub-panel in the garage. Then you have all the flexibility later to add whatever you need in and around the garage.

 

[mike93lx]

I was right to assume you must be in Texas. When my house was built in San Antonio they had to install the electrical so that the A/C units could be shut off from outside the house, without going inside the garage to the real "main" panel with all the house 120 volt breakers. I think mine may have also had the oven and water heater 240 volt circuits on that outside panel. Always thought it was a little weird, but I had no issues.

I don't know what other local code requirements apply to a setup like this where you wire through an exterior panel for all the circuits. If you have to go through all the trouble to fit in a bigger panel you may want to add a 240 volt breaker that serves a new sub-panel in the garage. Then you have all the flexibility later to add whatever you need in and around the garage.

A disconnect at the a/c is required everywhere in the US. If the panel is at them, that could serve as disconnect, but a pull out disconnect is standard

 

[KPtexan05]

I was right to assume you must be in Texas. When my house was built in San Antonio they had to install the electrical so that the A/C units could be shut off from outside the house, without going inside the garage to the real "main" panel with all the house 120 volt breakers. I think mine may have also had the oven and water heater 240 volt circuits on that outside panel. Always thought it was a little weird, but I had no issues.

I don't know what other local code requirements apply to a setup like this where you wire through an exterior panel for all the circuits. If you have to go through all the trouble to fit in a bigger panel you may want to add a 240 volt breaker that serves a new sub-panel in the garage. Then you have all the flexibility later to add whatever you need in and around the garage.

Yeah, I'm actually in the SA area! I'm so frustrated that they installed this crappy Eaton BR main lug panel, but I understand code allowed it as long is it takes less than 6 breaker throws to shut off all power. My last house in the Dallas area built around the same year had an Eaton CH main breaker panel and subpanels right inside the garage. Adding a 240V receptacle would have been a piece of cake. I've got the hook up on Square D gear, but I'll still need to pay electrician labor. Off to find a suitable electrician now...

 

[75gmck25]

I guess my explanation was confusing. Local code in San Antonio requires the ability to turn off the 240 volts circuits to the A/C units (and maybe other 240 volt devices?) from a single point outside where the service enters the residence. This is in addition to the A/C service disconnect, which would be close to the condenser. I don't know the exact wording of the requirement, and its been a long time since I've looked at that installation (house has been sold).

I was told it was related to local fire code and protecting the fireman from energized circuits while putting out a fire. They can cut power to major circuits in the house without pulling the meter. YMMV.

 

[wyliesdiesels]

Yeah I thought I read somewhere it can be in conduit sleeve to protect it but shouldn't be in an end to end run of conduit. You're right, looks like it's OK, which would make more sense to me.


True, I'd much rather deal with THHN or something here, but was thinking a conduit run all the way from the panel to the wall box may not be possible.

SER doesnt even need to be in conduit. it can be ran by itself indoors, and outdoors above ground, as long as its not subject to damage.

It can also be in end to end conduit. no prohibition on that either.

 

[KPtexan05]

it doesnt even need to be in conduit. it can be ran by itself indoors, and outdoors above ground, as long as its not subject to damage.

THHN can be run indoors without conduit? Or do you mean SER cable?

 

[wyliesdiesels]

THHN can be run indoors without conduit? Or do you mean SER cable?

SER

I edited my previous comment

 

[johnre]

Does it have an elbow that runs those cables vertically into the attic or is it open right after it gets in the wall? What is typical here?

Get an inexpensive borescope (or borrow one) and make a small patchable hole in the interior stud space so you can have a look at things - that will tell you what you are facing here.

Mine can get through an 8 mm hole, so it's not a big hole we're talking about.

And if you look at the bottom of your panel, there are likely other knockouts you could use in stepped sizes - you don't have to exit the same knockout as all the other wires. The four #6 wires needed for a NEMA 14-50 outlet will need a 1.25" fitting.

 

[sparky 1971]

Get an inexpensive borescope (or borrow one) and make a small patchable hole in the interior stud space so you can have a look at things - that will tell you what you are facing here.

Mine can get through an 8 mm hole, so it's not a big hole we're talking about.

And if you look at the bottom of your panel, there are likely other knockouts you could use in stepped sizes - you don't have to exit the same knockout as all the other wires. The four #6 wires needed for a NEMA 14-50 outlet will need a 1.25" fitting.

The panel knockouts punch out from the outside in, sometimes they can be blown out from inside out, but since the panel is mounted to brick, that probably ain't happening. And if he does manage to get it out, it needs a connector which will require a hole in the brick that's larger than the knockout.

A 14-50 at 50 amps would need a 6/3 romex, at 40 amps an 8/3, both of which have a #10 ground. In conduit, three #8 THWN and a #10 for 50 amps. Either romex will easily fit in a 3/4 connector and the THWN would fit in a 3/4 conduit, if EMT, he could do away with the ground. No reason here for 1-1/4 anything. The UF would require a larger connector since it's flat but there's no reason for it.

EDIT: it looks like the panel is recessed in the brick so I take back my previous statement about the knockout being next to impossible. There's still no reason for four #6 or a 1-1/4 fitting.

Get a long 1/4" bit and drill through the center of one of the 1/2-3/4 combo knockouts at the bottom of the panel. Stop when you get through the sheathing and take the bit out of the drill and use it to feel around in the wall. You could also use a coat hanger or piece of really stiff wire. If you don't feel anything other than insulation, chuck the bit back up and go on through the inside wall. Then, with a hole saw a little larger than a 3/4 romex connector, drill through the wall to the panel. You'll probably need an extension to get through the outer layer. If you're lucky, you will wind up at the knockout, but don't drill into the panel. Go back out and remove the rest of the knockout to 3/4, you might need a varibit to get it all the way. From inside the house, put a romex connector on a piece of 6/3 or 8/3 with about 18" if cable to go in the panel. Push it through the hole and go put the locknut on the connector in the panel. Shove extra wire inside the wall to make it easier when the panel change happens. Mount a 2-1/8 deep 4X4 box over the hole inside and mount the receptacle there.

 

[johnre]

A 14-50 at 50 amps would need a 6/3 romex, at 40 amps an 8/3, both of which have a #10 ground. In conduit, three #8 THWN and a #10 for 50 amps. Either romex will easily fit in a 3/4 connector and the THWN would fit in a 3/4 conduit, if EMT, he could do away with the ground. No reason here for 1-1/4 anything.

Agree, I misstated conduit size; 3/4" will do it.

But OP says that it's a 240V 14-50 outlet, meaning the breaker and wire should be sized for a 50 A system, and that means #6 copper wire.

Undersizing the ground is usually allowed if you aren't in metal conduit, but I use PVC and I don't bother undersizing ground just to save a few dollars.

 

[sparky 1971]

Agree, I misstated conduit size; 3/4" will do it.

But OP says that it's a 240V 14-50 outlet, meaning the breaker and wire should be sized for a 50 A system, and that means #6 copper wire.

I know what it is. If he wants to use Romex or UF it will need to be 6/3 for 50 amps. If he would want to size it to 40 amps, that is perfectly acceptable and could be 8/3 because there is no such thing as a 40 amp receptacle. 8/3 and a 40 is probably utilized way more than 6/3 and a 50 for ranges. And...if it's in conduit and THHN/THWN-2 is used, #8 is fine. Look at the 90° column in 310.16, but that's for derating purposes, the 75° has the final number. Romex and UF are sized by the 60° column per 334.8 even though 334.112 states the insulation has to be rated at 90°.

Undersizing the ground is usually allowed if you aren't in metal conduit,

If you're in metal conduit that is continuous from end to end, the NEC doesn't require a ground at all, undersized, oversized, or just right.

but I use PVC and I don't bother undersizing ground just to save a few dollars.

It doesn't matter if it's in EMT, Rigid, FMC, FNMC, PVC or anything else, a #10 ground is allowed for a 40, 50, or 60 amp circuit. and it can be more than a few dollars saved if it's a long pull. Both of the types of cables I listed above come from the factory with a #10 ground. And...even though four #6 will fit in a 3/4, who wants to work that hard? When I pull four #6, it for something three phase with a neutral and it's getting a 1" pipe.

I started doing electrical work in 1994, I had a journeyman's license in 1998, a masters since 2008, and a contractors since 2010. I don't know it all, don't claim to know it all, and don't want to know it all. But what I do know, I know well. You're aren't going to convince me to change my mind on this particular topic.

 

[nadogail]

Follow the rule of 7 P's, Proper Prior Planning Prevents P*** Poor Performance.

Put the new compliant Main Entrance Panel in first, then build your "Down Stream" Welder and EV Charger hookups.

 

[johnre]

If you're in metal conduit that is continuous from end to end, the NEC doesn't require a ground at all, undersized, oversized, or just right.

Poor wording on my part, sorry. I should have left out the part about metal conduit and just said that the ground wire is allowed to be undersized. I'm aware that no ground wire is needed with metal conduit.

If he would want to size it to 40 amps, that is perfectly acceptable and could be 8/3 because there is no such thing as a 40 amp receptacle.

Honest question here, then: My 50 A hardwired EVSE equipment states in the manual to use a 50 A breaker and service, which I did (hence the #6 copper). A plug-in version of this EVSE wasn't an option for me (the state of Oregon rebate wasn't given unless you hardwired it), but I would have preferred it that way - then I would have other shop uses for this receptacle possible. If I instead got the plug-in model (or converted mine to plug-in, which I think is possible), is it entirely up to me to assure there's a 50A breaker and service provided to this L14-50 outlet? I'm guessing the EVSE and vehicle are going to try to take the full rated 40 A from the line that it thinks is possible, and that would overload the 40 A breaker, yes?

And...even though four #6 will fit in a 3/4, who wants to work that hard?

This time I Iooked to make sure, yep I'm in 3/4" PVC. And three was not that easy, you're correct (I left out neutral, which I guess leaves me unable to put in an L14-50R receptacle without a lot more work here).

 

[sparky 1971]

Honest question here, then: My 50 A hardwired EVSE equipment states in the manual to use a 50 A breaker and service, which I did (hence the #6 copper). A plug-in version of this EVSE wasn't an option for me (the state of Oregon rebate wasn't given unless you hardwired it), but I would have preferred it that way - then I would have other shop uses for this receptacle possible. If I instead got the plug-in model (or converted mine to plug-in, which I think is possible), is it entirely up to me to assure there's a 50A breaker and service provided to this L14-50 outlet? I'm guessing the EVSE and vehicle are going to try to take the full rated 40 A from the line that it thinks is possible, and that would overload the 40 A breaker, yes?

The EV is going to be considered a continuous load, which is defined as being used for three hours or more a time. Circuits for continuous loads are sized at 125% of the load, or in other words, the load is 80% of the circuit. So, your EV is going to be somewhere around 40 amps. (40X1.25=50 amp circuit or 50 amp circuit X.8=40 amp load.) Because of the fact that there is such thing as a 45 amp breaker available which is what 125% of 36 amps, it's safe to assume that your car uses between 36 and 40 amps while charging. You could plug it into a 40 amp circuit and never know the difference but technically, you would be "overloading" the circuit according to the NEC. And no, unlike what many people think, the breaker won't trip after three hours. A 40 amp breaker can run along just fine at 40 amps output, and possibly a little more, indefinitely.

And...regardless of what you were told or read, since you used PVC, you probably used THHN/THWN, you could have used #8 wire for the current carriers. Also, there is nothing wrong with oversizing the ground, but there is no reason for it, #10 would have been fine in your case. The ground is there to carry any fault current back to the panel in order to trip the breaker. which happens almost instantaneously so there is no concern with overloading it. 99.9999 to infinity% of the time, the ground wire does nothing but sit there waiting for something bad to happen.