60A sub panel in garage, fed by 6ga THHN?

[Noltz]

A while ago I ran 6/6/6/6 THHN into my garage for a future EV charger. Right now it's protected at 50A with a NEMA 14-50 plug on the end of it. I'm looking at adding a medium size metal lathe in the garage for a hobby. Most require 20A @ 240v single phase.

Question; Should I put a 14-50 plug on the lathe and just use the same receptacle, swapping them when necessary? Or should I swap the current receptacle and put in a small 60A sub panel & upsized breaker, with dedicated receptacle's for each component. Is this even allowed?

Thanks,

 

[a_whale]

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[wyliesdiesels]

A while ago I ran 6/6/6/6 THHN into my garage for a future EV charger. Right now it's protected at 50A with a NEMA 14-50 plug on the end of it. I'm looking at adding a medium size metal lathe in the garage for a hobby. Most require 20A @ 240v single phase.

Question; Should I put a 14-50 plug on the lathe and just use the same receptacle, swapping them when necessary? Or should I swap the current receptacle and put in a small 60A sub panel & upsized breaker, with dedicated receptacle's for each component. Is this even allowed?

Thanks,

why did you use #6 for the ground wire? and is it green if not thats a code violation.

i would put in a subpanel

is this garage attached or detached?

 

[Terry D]

why did you use #6 for the ground wire? and is it green if not thats a code violation.

i would put in a subpanel

is this garage attached or detached?

Would that be a code violation in Canada

Sent from my SM-G960U using The Garage Journal mobile app

 

[wyliesdiesels]

Would that be a code violation in Canada

Sent from my SM-G960U using The Garage Journal mobile app

oh whoops. no clue..... didnt notice that the OP is in canada

 

[Noltz]

It seems like it would be a heck of a lot more convenient to put a subpanel so that you could have both available without swapping cords. Is this an attached or detached garage?

That's what I'm thinking too. Attached garage, ~45' run. I got the wires as a package bundle for a great price, so that's what went in. Yes the ground is green.

Is it allowed to have two 240 outlets from one breaker? Do I need a panel, or can I just install the outlets?

 

[a_whale]

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[Noltz]

No, definitely no way I'd be making a connection at the outlet like I would with a 120v outlet. Fitting four 6ga wires into a double box was tight. I would definitely need to make the connection on the line in it's own junction box. Fortunately all my runs are surface mounted so I can make these sorts of changes without too much trouble.

I'd still love to hear an electricians input. I am in Ontario.

 

[Syberia]

The problem would likely be that the lathe specifies a 20 amp breaker, and an EV charger will want 40-50 amps. I'd do the subpanel, you can run additional 120v circuits off of it as well.

 

[pattenp]

Electricans can verify, but I don't think there are any problems with 2 x 240 outlets run from one breaker... There certainly is not with 120V. However, you might find that your 240V outlet itself is not rated for dual connections, so I suspect you'd need a junction box somewhere between them. No way I could fit a 240V outlet *and* a wire nut splice in the metal outlet boxes I have for that guage of wire.

Here in the US if subject to the IRBC (International Residential Building Code) multiple receptacles on a single circuit are limited to 20A, so multiple 240V is okay as long as they don't exceed 20A.

 

[Noltz]

Here in the US if subject to the IRBC (International Residential Building Code) multiple receptacles on a single circuit are limited to 20A, so multiple 240V is okay as long as they don't exceed 20A.

So in this case it's a no-go. It'd be fine if I'm running multiple machinery pieces but because I'm planning on an EV charger I either have to swap the plug each time or use a sub panel. Okay, good to know.

 

[a_whale]

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[JKJEFF]

A small sub panel is so cheap and easy why would you not use one?

 

[pattenp]

Haha, oh man. There are so many of these international code pushers I can't even keep up anymore. The more there are, the more expensive it becomes to "conform". I wired up dual outlet 240V 50A outlets in my last place, and I'll be doing the same in this one. As long as the conductors and splices are rated for the upstream breaker I see no problem with this

I'm not pushing anything. Just providing information. What you do is totally your business.

 

[a_whale]

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[pattenp]

Oh I didn't think you were pushing it at all, and I appreciate the FYI! I just throught it was funny to learn about yet another international code consortium. It's a meme nowadays. Big money maker.

Surprised you don't know of it since I believe Michigan has adopted it.

 

[a_whale]

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[mike93lx]

I can't imagine not putting a subpanel in

 

[theoldwizard1]

A small sub panel is so cheap and easy why would you not use one?

Concur !

What everyone seems to miss is that the SIZE of the sub panel in either amp or spaces is really not important ! It is the size of the breaker feeding it from the other panel and the size of the wire.

If you install a 100A sub and it is feed from a 60A breaker with appropriate wire it just means you have a longer walk to reset that breaker when it trips !

 

[Solarphil]

Concur !

What everyone seems to miss is that the SIZE of the sub panel in either amp or spaces is really not important ! It is the size of the breaker feeding it from the other panel and the size of the wire.

If you install a 100A sub and it is feed from a 60A breaker with appropriate wire it just means you have a longer walk to reset that breaker when it trips !

Feeding a higher rated panel from a lower rated breaker is pretty normal, and no problem. Connecting more *load* to that subpanel than what was designed for can be a nuisance, due to trips as you noted, but it’s not a safety hazard. It may technically be a code violation if you’re an electrician and didn’t adequately assess the load and install a properly sized and coordinated system, but at least it will fail safe.

Getting back to the original post’s question, putting a 14-50 plug on a tool that requires a 20 amp protection and then feeding it from a 50 amp supply would be a really, really bad idea. You effectively would be making the motor windings the sacrificial “fused element” in the circuit, and you don’t want to be there on the day the motor stalls.

The best, cheapest and most flexible solution is to put a small subpanel where the existing 14-50 receptacle is, and then feed both the 14-50 and new 20 amp receptacle from properly sized breakers in that panel. At a swag you should have enough diversity of load between EV charging and running your lathe that you don’t have to recalculate your service or supply.

 

[Solarphil]

If you absolutely positively don’t want to install a subpanel foe whatever reason, the other way to solve the problem is replace the 50a breaker at the main panel with a 20a, then replace the 14-50 receptacle with the right one for your lathe. You’re then SOL for future EV charging, but you can power your lathe safely for around twenty bucks.

 

[Noltz]

The subpanel option is definitely the best option if I end up with some machinery in the garage then. Set it and forget it. Thanks all.