Looking for some opinions on wiring for small basement shop

[Peter Hartman]

My original plan when I built this house was that I would be building a metal building shortly after. As things go we went way over budget on the house so now my only option is to move into a unfinished room in the basement. Since I didn't plan on running any power tools down there I didn't run much wire for power tools. I have 3 12awg 20amp 120v circuits ran to junction boxes down there. I could commondere 2 of these runs for the shop, and I could probably make do, but I would like more. The furnace is a heat pump with back up heat strips. I ran a 60amp 6awg run down to those. I would like to pull that, run it to a sub panel and create 2 30amp 220 runs. Do you guys see any problems with that? I picked up a 100 amp panel from Home depot the other day. It has 6 spaces. Our primary heat source is a wood stove so the heat strips will rarely be used, and when they are it will probably be in the very early morning hours when we will be sleeping.

[Joseph Tarantino]

My original plan when I built this house was that I would be building a metal building shortly after. As things go we went way over budget on the house so now my only option is to move into a unfinished room in the basement. Since I didn't plan on running any power tools down there I didn't run much wire for power tools. I have 3 12awg 20amp 120v circuits ran to junction boxes down there. I could commondere 2 of these runs for the shop, and I could probably make do, but I would like more. The furnace is a heat pump with back up heat strips. I ran a 60amp 6awg run down to those. I would like to pull that, run it to a sub panel and create 2 30amp 220 runs. Do you guys see any problems with that?

there's no need to run 30A 220v runs, unless a welder is in your future. 20A 220v circuits will run almost anything that has a role in a hobbyist's workshop, IMHO.

I picked up a 100 amp panel from Home depot the other day. It has 6 spaces.

IMHO, return it for a panel with more spaces. unused spaces don't cost materially more if they aren't used. if you need more spaces in the future, the panel would need to be replaced or augmented with an additional sub panel.

Our primary heat source is a wood stove so the heat strips will rarely be used, and when they are it will probably be in the very early morning hours when we will be sleeping.

i'm curious to see if you get any materially different information here than was posted on lumberjocks.

[Peter Hartman]

Who are you quoting in the blue?

I disagree with the first statement. Many 2-3 hp 220 motors use over 10amps. So for example if I get THIS dust collector (http://www.oneida-air.com/inventoryD.asp?item_no=XGK020105H&CatId={7F6C8978-92E8-4902-9A37-D8A254EDF4FC}) and try to run my table saw on the same circuit I am going to flip the breaker.

[Jim Neeley]

I too disagree. FWIW, my table saw, Clearvue Cyclone and Ingersoll Rand Compressor all require >20A breakers.

[Rod Sheridan]

A 20 ampere circuit is fine for a 3 HP motor, if it's a good motor.

If it's a cheap low PF, low efficiency motor it may not be adequate.

I have 2 X 4 HP combination machines, which use a 20 ampere circuit.

The OP has a couple of 20A 120v circuits which may be used for his dust collector or general tools.

One 20A 240V circuit will be all he needs in addition, or he could also wire it as a multi-wire branch circuit and run 120V receptacles as well as 240 receptacles from it.

Regards, Rod.

[David L Morse]

There's no need to waste two spaces on the 60A breaker for the heater in your shop panel. Just tap into the main lugs with the feeder. It's already protected with the breaker in the main panel and that will give you an additional 220V circuit.

[Wade Lippman]

There's no need to waste two spaces on the 60A breaker for the heater in your shop panel. Just tap into the main lugs with the feeder. It's already protected with the breaker in the main panel and that will give you an additional 220V circuit.
Interesting point. It makes sense, but that doesn't mean it satisfies code.



I've owned 8 3hp tools. Only one, a griz cyclone, required more than 20a.

[Joseph Tarantino]

Who are you quoting in the blue?

the blue lettering are my replies to the question/issue raised immediately preceding it.

I disagree with the first statement. Many 2-3 hp 220 motors use over 10amps. So for example if I get THIS dust collector (http://www.oneida-air.com/inventoryD.asp?item_no=XGK020105H&CatId={7F6C8978-92E8-4902-9A37-D8A254EDF4FC}) and try to run my table saw on the same circuit I am going to flip the breaker.

yes, that's true as the linked DC draws 11.5A @ 220v and a decent 3 hp TS will draw~ 15A @ 220v. but i was under the impression that several 220v circuits were planned for your installation. each of those previously suggested tools above (DC and TS) will be easily accommodated by a 20A 220v circuit. in my own 30A sub panel powered shop, i ran a 3 hp unisaw (16A @ 220v) and a delta 50-850 (6.5A @ 220v) on the same 20A 220v circuit without incident.

or am i misunderstanding the purpose of your intention to install several 220v circuits in your shop?

[David L Morse]

Interesting point. It makes sense, but that doesn't mean it satisfies code.



I've owned 8 3hp tools. Only one, a griz cyclone, required more than 20a.

How does it violate code?

[Jim Neeley]

Interesting point. It makes sense, but that doesn't mean it satisfies code.

Wade,

Would you please provide the code reference forbidding it?

You would obviously need to ensure the main lugs are rated for two connections.

Jim in Alaska
(EE PE but always learning)

[David L Morse]

You would obviously need to ensure the main lugs are rated for two connections.
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Or user these http://www.thomasbetts.com/ps/fulltilt/index.cgi?part=10HPS

[Wade Lippman]

Wade,

Would you please provide the code reference forbidding it?

You would obviously need to ensure the main lugs are rated for two connections.

Jim in Alaska
(EE PE but always learning)
I didn't say it did. I simply said that being good idea didn't mean it was code compliant.
In this case code might not allow it because later on you could upgrade the cable and breaker to the subpanel, leaving heating circuit unprotected. That sort of thing wouldn't surprise me. I simply don't know.

[Peter Hartman]

yes, that's true as the linked DC draws 11.5A @ 220v and a decent 3 hp TS will draw~ 15A @ 220v. but i was under the impression that several 220v circuits were planned for your installation. each of those previously suggested tools above (DC and TS) will be easily accommodated by a 20A 220v circuit. in my own 30A sub panel powered shop, i ran a 3 hp unisaw (16A @ 220v) and a delta 50-850 (6.5A @ 220v) on the same 20A 220v circuit without incident.

or am i misunderstanding the purpose of your intention to install several 220v circuits in your shop?

I am not sure how everything is going to lay out, but I may end up with the DC and a saw or the DC and the planer on the same circuit, and that will put me over 20amps. Having a 30amp circuit also leaves the door open to some of the old 5hp machines that are floating around for good deals, provided it is single phase.


Wade,

Would you please provide the code reference forbidding it?

You would obviously need to ensure the main lugs are rated for two connections.

Jim in Alaska
(EE PE but always learning)


I know that a panel cannot be used as a junction box. That sounds like a junction to me. I am sure it would just come down to who the inspector was. I am not short on space, so I am not that worried about the space or spending 7 bucks on a 60 amp breaker. I would like to know definitively if this is legal though.

[Michael W. Clark]

Why not put the DC on a dedicated circuit? Saw, planer, etc on the other 220 circuit. The DC will be running any time the others are running.

Hire a competent electrician to come out and look at your application. They can give you some options and relative pricing, plus they are familiar with your local codes. It will be worth it.

[Peter Hartman]

How does it violate code?

I have read some of the code that says the panel cannot be used as a junction box. I don't know if that would count as a junction or not. It would probably come down to the inspector.



Why not put the DC on a dedicated circuit? Saw, planer, etc on the other 220 circuit. The DC will be running any time the others are running.

Hire a competent electrician to come out and look at your application. They can give you some options and relative pricing, plus they are familiar with your local codes. It will be worth it.

I probably will keep it on a dedicated circuit, but the cost of 10/2 wire vs 12/2 is comparable so I don't see any reason not to upsize it.

I may consult the electrician at the local hardware store, but I won't be hiring this out. I just wired the whole house myself, this seems pretty trivial.

[David L Morse]

I have read some of the code that says the panel cannot be used as a junction box. I don't know if that would count as a junction or not. It would probably come down to the inspector.

Is this the part you read?

409.104 Wiring Space.
(A) General. Industrial control panel enclosures shall not
be used as junction boxes, auxiliary gutters, or raceways for
conductors feeding through or tapping off to other switches
or overcurrent devices or other equipment, unless the conductors
fill less than 40 percent of the cross-sectional area of the
wiring space. In addition, the conductors, splices, and taps
shall not fill the wiring space at any cross section to more than
75 percent of the cross-sectional area of that space.

Be sure to reread the part after "unless".

[Michael W. Clark]

The reference to hiring a local electrician was based on my experience that if you pay them for their time, you get a more technical and unbiased opinion. The guy at the hardware store may be great, but what is his incentive behind the advice, sell parts or services, maybe he is retired and it's OK.

I wired my basement and workshop myself. I paid an electrician for a few hours of his time to help with layout and questions. I pulled permits and it was inspected. Just some assurance if you need a definite answer if it will meet local code.
Mike