Electrical wiring question - shop related

Is it permissable to have an outlet that is rated for less curent than
the circuit breaker is?
I wired the detached garage for 40A 220v service (it seemed like a lot
of capacity 25 years ago!). In the garage is a subpanel with (4) 110V
and (1) 30A 220v circuits. Originally the 30A breaker fed one single
outlet (for the arc welder and compressor that I would someday own) -
eventually I got tired of unplugging the welder to plug in the
compressor or phase converter and now have (3) 220v outlets side by
side in one box. Over the years I made up an extension cord to be able
to weld on the opposite side of the garage and to power the bandsaw.
I am considering adding an outlet at the bandsaw. The bandsaw has a
15A 220v plug on it. So back to my original question is there an
issue with having a 15A outlet on a 30A circuit (the circuit is wired
in #8 romex)?
Reply to
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snipped-for-privacy@c3net.net fired this volley in news:3591bfb5-06bc-4d92-9cf7- snipped-for-privacy@t8g2000prh.googlegroups.com:
Yeah, there is. You could draw enough current to char or even destroy the outlet.
What you need is a small local service box with a breaker just for that outlet. They sell them at the home stores variously named like "job site panel". They come with a breaker (or a place to put one), and often one 220V outlet and one 115V duplex outlet.
Reply to
Lloyd E. Sponenburgh
C'mon, LLoyd. Wouldn't it be both legal and saner (not to mention far CHEAPER) to simply replace the -breaker- with a smaller one?
P.S: That #8's gotta be a striped beeyatch to work with.
-- You can't wait for inspiration. You have to go after it with a club. --Jack London
Reply to
Larry Jaques
Yes, but then how's he going to pull 30A on the line when the welder and compressor run simultaneously?
I ran some 6-3 from my basement to my attic for a future subpanel. Not only is the stuff unruly, it's also just plain heavy.
Reply to
Larry Jaques fired this volley in news: snipped-for-privacy@4ax.com:
He has other, higher-current needs for that circuit, from the way I read it.
Reply to
Lloyd E. Sponenburgh
Logic would dictate that you would NOT want to have an outlet that will fail before the breaker trips. I would expect that the NEC would say the same. Simple solution would be to change the outlet. That's a lot cheaper than rebuilding your shop after the fire. :-)
Reply to
Jim Chandler
My garage subpanel is maxed out and I do not want to derate the 30A breaker for when I use the welder (technically the welder is rated to draw 50A but I have only tripped the 30A breaker once in the last decade). I have a 40A breaker at the main service panel in the house. It is set up this way so that I do not trip the breaker in the house - I do not live there anymore and I don't want to rely on my tenant being home to reset a tripped breaker (on demand). If I could start all over I would have a 60A breaker in the house and 50A breaker in the garage with a larger subpanel.
LLoyd: The "local service panel" would be mounted at the 20A location or adjacent to the existing subpanel? So there would be a local subpanel off of the existing subpanel in the garage? By extension, would I be correct in presuming that putting a higher amp rated plug on the bandsaw would not be proper either? Not that its correct, but today my bandsaw is powered by an 8 ga extension cord that has a 50A male plug and a 15A female recepticle on the other end that the bandsaw power cord plugs into.
Reply to
No. Its also potentially dangerous if you have a problem.
I have a 50 for my welder and 30s for my table saw and future compressor. Each is a different type of plug and outlet. 40amps isn't much. Its time to start thinking about upgrading your service to that area.
I hope its some really heavy duty cord. Heavier than the heaviest 110 cord you might find in a good hardware store.
Yes, there is an issue. You could theoretically have a problem and draw enough power to start a fire without tripping the breaker.
Reply to
Bob La Londe
Does not meet code, but you COULD put a fuse or breaker in the outlet box to protect the outlet to 15 amps.
Reply to
Because the 15A outlet is not the only outlet on the circut I think that's allowable. The small one circuit breaker panel is not a bad idea though. I'll have to run this one buy my electrian friend, see what he says.
Thank You, Randy
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Reply to
Most 3 phase equipment shop that I have seen had a fused disconnect on the machine. If I were to do similar on my band saw: a fused (15 amp) disconnect for the 220V 1 phase, attached to the machine. Coming out of the disconnect box a power lead going to the 30A outlet. I am considering having the outlet in the ceiling or in a vertical step in the ceiling. The band saw is positioned between 2 car bays in the garage (not near a wall) and the ceiling steps up from 8 ft to 9.5 ft over the band saw. I figure that a powercord opposite of the throat of the machine would be protected by the machine.
Reply to
In only one limited case.... The NEC allowed/allows classic 15A outlets on 20A circuits. AFAIK, that's the only case.
Reply to
David Lesher
Yes, it's legal for 120 Volt but a lot of people try that for 240 with a single fuse or a single pole breaker. Fires and electrocutions aren't worth the few cents they save. :)
Reply to
Michael A. Terrell

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