How Much Power?

[max_in_graham]

In talking with my electrical contractor today, we're going to do some trenching to get power out to a couple of HVAC units, and isolation transformer and power to a small electronics shop.

He suggested that while we're trenching, that we go ahead and trench all the way to the new woodshop.

My question is this... about how much power (phase, amperage and #circuits) would make sense to put in a 12x16 shop?

Thanx!
Max

[Woodman2k]

Max,
if your going through the trouble I would go at least a 100 amp service for a shop that size.

[meika123]

I ran 100 amps to my 20' x 20' shop, and haven't had a single problem.

[Bas]

I have a shop that's 350sqft., and I have two 120V 20A circuits (tools), one 120V 15A circuit (lights), and one 240V 20A circuit (table saw). That's on the sparse side, I probably should have added another 120/20 and 240/20 circuit. It largely depends on what kind of equipment you're running of course. A scroll saw and a shop vac don't need much.

As for amperage, 60A should be sufficient. Even if you ran your table saw, dust collector, air cleaner, fridge and lights all at once, I don't think you'd get over 40A. If there's even a remote chance you're expanding the shop in the future, or you plan to run larger equipment like a 5HP cyclone or 12" table saw, you may want to oversize the wiring, and go with a 100A sub panel. Assuming you're using PVC conduit, not underground cable, the additional cost wouldn't be that much more. You really don't want to save a few dollars now only to dig another trench later.

As for phase, the "smaller" woodworking equipment is all single phase. If you plan on getting some serious cutting tools, then 3-phase would be advisable, but I don't see that happening in a 12x16 shop...not unless you plan to house only one tool

[DaveO]

As much as you can afford. It is much easier to add more power than you'll need than to wish you had it later. At this point it's cheap. I have 200 amp service to my basement shop (fell into that because it was wired for an automotive shop before I bought it). I have since found that a lot of the addition above my shop is tied into that service, but I am still not lacking for power. Despite some serious Jackleg wiring, I haven't come close to blowing a breaker yet. I have 2 240 volt 30 amp circuits and 7 120 volt 20 amp circuits available.
More than I will ever need...unless I need three phase


Dave

[cpowell]

To be honest a 240V, 60A service would probably do all you'll ever need. If you think you may expand some day then run 100A.

I assume this is for 120/240V single phase WWing machinery.


Chuck

[Gotcha6]

100 amp panels typically have room for 16 circuit breakers. That would be enough capacity for 4 230 volt breakers & 8 120 volt breakers. I can't imagine needing that much power in a 16 x 24 shop.
60 amp panles are the next size down usually & they typically have room for 6-8 breakers. They are also fed by a lot smaller conductor. I'd go with the 100 amp just for the difference. If you expand the shop later on, you can always utilize the surplus.

[max_in_graham]

Thanks for the suggestions!

At this point, the studio has 400Amp service entrance. We're only taping 200 in the building, so there's PLENTY to spare.

I'll talk to the contractor tomorrow about running a 100Amp service line to the building. It might be a bit tricky as it will be coming off another sub panel... the electrician will know what's code.

Thanx again!
You guys are GREAT!... I'm so glad I found this place!

Max

[junquecol]

The main thing is to NOT USE UF cable, but PVC conduit instead. This way wires can be changed out, or added later. Also run a separate conduit for phone line to shop. Use at least 3/4", with 1" being my choice for the power feed. In my shop, I have a 75 amp feed, and it has never failed me. Biggest draw in my shop is stick welder. It is supposed to be on a 50 amp breaker, but son needed that size breaker for his hot tub, so I changed it out for a 40 amp breaker that I had. Gave him the 50. In a one man shop, very seldom are you going to be using more than one machine, lights and DC. Total draw of less than 30 amps.

[max_in_graham]

Oh you can believe we're not gonna do UF.

I think we're planning on using whatever we use for the main feeder to HVAC units... either 1" or 1.5".

I may end up running individual circuits up to the studio, so I'd rather have PLENTY of room to pull another dozen lines than have to worry about digging another 150 ft trench.

Phone is not a problem. I'll use our cordless out there... the shop is about 50 ft from the house. I'm also running a wifi network for the studio's clients, so no worries for internet access when I get myself in a major woodworking bind... and have to come here beggin' for help.

Max

[McRabbet]

Even though you might plan to use cordless phones in the shop, I'd still put in the 1" conduit that Junquecol recommended to carry phone or video or cable TV coax or CAT5 or who knows -- you won't regret it unless you find out later you should have done it! I'd vote for the 100 AMP service, too -- cost of larger panel is negligible and wire cost difference should not be a major addition either.

[flyrod444]

Max,
Will you ever expand the shop in the future? 100 amp's should be plenty for a shop of that size, but if it ever gets larger is the question. Our local power company just started Runing underground to a meter base for free. The best thing is they only charge you for the electricity used no more minimum bills on a meter. They ran Underground 200' to my shop' meter base for free. I put a 200 amp service in to cover what I need in my shop. You might want to check with your local power company, If they dig the ditch and supply the wire for free it is hard to pass up. The going rate for a ditch around here is $2.00 a foot.
Jack

[Mike Wilkins]

I currently have a 100 amp panel in my 16 X 24 shop, with an attached 16 X 16 storage room. All the 120v lines are on 20 amp circuits with #12 wire, and 2 240V lines on 30 amp circuits with #10 wire. Go with a 100amp box just in the event you are able to expand in the future.

[DaveD]

Your original question also mentioned 'phase' If you also have the capability to get 3 phase you might want to think about putting in a separate empty conduit so you could hook up 3 phase if you needed it.

Now you really don't need it for woodworking (unless you want a BIG machine) but if you get into metalworking and want to run a decent mill or lathe (think in the $3-5K range each machine) you can really take advantage of 3 phase power. Don't have to muck with phase converters either. Sometimes you can also get 3 phase used machines for scrap prices since 3 phase implies industrial area/zoning.

In any event consider putting in bigger conduit(s) than you need. Its much easier to pull wire through a bigger conduit. When you pull the wires remind your electrician buddy to use plenty of 'goose grease' Much easier to pull the wires.

Finally, I vote for 100Amp minimum capability (wire and panel).

More power/conduits could also be a selling point if you ever plan to sell.

[mkepke]

Practically speaking, 60A should be sufficient. I have that much in my 24x36' shop, servicing a 5HP sander, 2HP DC, 1.5 HP air compressor, lights, radio, battery chargers.

I do wish I had 100A so I could also run my 30A AC unit w/o fear of kicking the subpanel disconnect.

But you aren't going to have a 30A AC unit in a sub-200 ft^2 shop either...

-Mark