[lb0190]

Hello,

I would appreciate input on an idea I have in respect to safety and code. In my garage, I do a little wood working and need a 15amp duplex outlet in the ceiling for a new retractable extension cord.
In the nearby ceiling area I have a single outlet , 30amp 120vdc circuit that powers a dust collector where the startup surge draw is 18 amps. I need a 15amp 120vac outlet in the same area and I want to avoid (if possible) running wires from the load enter.

Do you think it’s safe and within code to pickup the current at the 30amp outlet using the same 10awg wire for a three foot run to a 15amp breaker that would feed a 15amp outlet? I do not see any combination of equipment hooked up or running at the same time where the draw would exceed 30 amps.

Thanks in advance.

 

[HandyAndyInNC]

No, you cannot do that. That is just begging to get someone killed. Pull a few dedicated circuits so that you can have more later on and be done with it.

 

[rjniles]

Definitely not compliant and hazardous.

 

[Missouri Bound]

No, you cannot do that. That is just begging to get someone killed.

And how would that happen?

 

[Missouri Bound]

Definitely not compliant and hazardous.

Code reference?

 

[rjniles]

Code reference?

You are being ridiculous. You can not connect a 15/20 amp receptacle to a 30 amp circuit.

 

[Missouri Bound]

You are being ridiculous. You can not connect a 15/20 amp receptacle to a 30 amp circuit.

So you don't have one?

 

[Missouri Bound]

What you can do is add another box to the circuit and wire it with #10 wire.
Then purchase what is called a "fused receptacle". It will be a single outlet with a fuse that fits into a regular box. That fuse will protect only that receptacle.
They are 15 amp receptacles. All you need then is a 15 amp fuse to screw in place and you are done.

 

[CodeMatters]

I'd avoid this altogether if I could...but...if I were going to do this.... I'd
put small (maybe 4/8) panel ahead of the dust collector outlet and run both
outlets off that panel on different circuits.
May or may not meet NEC, would likely work fine w/o tripping breaker back
at panel, would definitely be safe.

 

[lb0190]

Thanks everyone for the quick replies. My common sense kept telling me I should just pull in new wires from the load center with a dedicated breaker and be done with it, but the “what if” kept coming up in my mind and I just had to look a little deeper with your help. When I installed the 30 amp service, I sized the conduit to allow more wires just in case something like this came up. I’ll take the cautious route and pull new wires.

 

[CodeMatters]

Thanks everyone for the quick replies. My common sense kept telling me I should just pull in new wires from the load center with a dedicated breaker and be done with it, but the “what if” kept coming up in my mind and I just had to look a little deeper with your help. When I installed the 30 amp service, I sized the conduit to allow more wires just in case something like this came up. I’ll take the cautious route and pull new wires.

Good forethinking. Sounds like you'll end up with 4 current carrying
conductors in your conduit. CEC would require derating to 80%.

Some things just have to be a pain.......


EDIT: T-5C for any Canucks following along

 

[rjniles]

so you don't have one?

210.20 (d)

210.21 (3)

 

[seharper]

Good forethinking. Sounds like you'll end up with 4 current carrying
conductors in your conduit. CEC would require derating to 80%.

Some things just have to be a pain.......

Not necessarily. You do understand how that derating works, right?

You don't just go "ooh, 30A x 80% = 24A, 15A x 80% = 12A and now we need to upsize all our wires".

You start with the max thermal rating for the wire ignoring termination limits (since the terminations are not inside the conduit), surely pulling off the 90C column. For #10 wire that is 40A. For #14 wire that is 25A. Now you derate. #10 becomes 32A, #14 becomes 20A.

Which makes that a nothingburger, since you're already limited to 30A and 15A respectively.

It really doesn't show up on your radar until either circuits >= 5, or circuits >= 4 and amps >= 40.