How much elec service capacity should I get?

[Glen Blanchard]

I am doing some planning for a new shop. Hobbiest only - one man shop. I have listed my stationary tools below, and want to have electrical capacity for a few more 220V tools should the need arise in the future. Will also have central HVAC, fluorescent lighting and obviously a myriad of hand power tools. Any ideas as to what electrical capacity I should tell my builder I need?



18" Bandsaw - 10 amp - 220 v - 2 hp
20" Planer - 30 amp - 220 v - 5 hp
12" Jointer - 18 amp - 220 v - 3 hp
Edge Sander - 110 v - 1.5 hp
Cyclone - 14.5 amp - 220 v - 3 hp
16" Bandsaw - 110 v - 1.5 hp
Drill Press - 110 v - 0.75 hp
Drum Sander - 110 v - 1.5 hp
Table Saw - 13 amp - 220 v - 3 hp
Compressor - 110v

[Matt Meiser]

Around here 100A seems to be pretty standard for an outbuilding. Remember that you won't be running all those tools at once. I have 100A service in my shop with no issues. I can run my AC (huge window unit), lots of flourescent lights, dust collector, and 1-2 power tools without even noticing.

[Ted Miller]

Glen, Power is like tools in our shops, the more the better. You can get by with 100 amps if your DC is 220v and of course you are running one 220v machine at the same time. In my last shop/3 car garage I had 50 amps and this new shop/2 car garage I have 70 amps. I still have 4 each 220v outlets and 14 each 110v outlets. But I am one guy and my DC right now is 110v...

[Ken Fitzgerald]

Glen,

When I built my new shop, I installed a separate meter and installed 200 amp service. Maybe some electrician will jump in and give you some advice.

[paul aubin]

see the link for a load calculator

/paul



"http://www.electricalknowledge.com/SFDLoadCalc.asp"

[Rod Sheridan]

Hi, since you only will be running one machine at a time, pick the largest (planer) and add your cyclone.

30 amperes plus 15 amperes = 45 amperes. Add 2X 15 ampere circuits for lighting (one per line, so only add 15 amperes)

This yields 60 amperes.

Normally, you would load a circuit to 80% continuous, which means you would need a minimum feeder ampacity of 75 amperes.

If it was a home shop, I would use the 60 ampere feeder as the planer would very infrequently run at full load. (The cyclone would be continuous, the planer perhaps 12 to 20 amperes).

Regards, Rod.

[Glen Blanchard]

I have seen much talk about sub-panels, full panels, etc. Does a sub-panel use an existing meter while a full panel means it will have its own meter?

[Paul Johnstone]

I have seen much talk about sub-panels, full panels, etc. Does a sub-panel use an existing meter while a full panel means it will have its own meter?

A subpanel is when you plug a breaker into your main electric panel and then run the wire to a new breaker box.. Typically you run 60-100 amps.. No electrician required if you know what you're doing.

I'd recommend that the OP get 100 amps. He could probably get by with 60 amps, but it won't be that much more expensive to go to 100.

[Rod Sheridan]

Hi Glenn, do you need a sub panel or does your existing distribution panel have enough spaces to accomodate the machinery planned?

Is your shop in your house or a separate building?

My shop is in the basement, I added a 60 ampere sub-panel (fed from main panel) and the following circuits;

- 240V 20 A circuit for cyclone

- two 15A 120V circuits for lighting

- one 120/240 20A circuit that feeds all the receptacles in the shop. The receptacles are all duplex, one is a 240V 20A, the other is a 120V 20A T slot with split circuits. There is one of each of these in a 4" box at intervals around the room for machinery.

In addition, there is a 120V 20A drop cord above the bench fed from a 120V 20A GFCI receptacle for portable power tools.

The above installation only requires 4 circuit breakers, 2 X 2 Pole 20A, 2 X 1Pole 15A for lighting.

Regards, Rod.

[Jim Becker]

100 amp minimum since HVAC is involved...with feeder cable rated higher in case you need to adjust upward in the future.

[Glen Blanchard]

Hi Glenn, do you need a sub panel or does your existing distribution panel have enough spaces to accomodate the machinery planned? Is your shop in your house or a separate building?

Right now there is dirt - nothing more. My new shop will be part of our new house - all of which is in its preliminary design stage. We will close on the lot in about a month, but will wait a while before beginning construction. We will have a 2 car garage that will be used for (what else?) cars, a single car garage that will be used for general storage and a seperate building, 34' x 22', which will become my dedicated workshop. The shop will be designed and framed to be an addtl 3 car garage. Someday, when we sell the house, this will give the new owners the option of using it as a garage in the event they have no use for a workshop. Although it will be framed to accept garage doors, I will not be putting them in as they are difficult to adequartely insulate and they block the fluorescent tubes when they are in the "up" position.

This is the preliminary elevation of the house. The workshop will be connected to the house via a porte coche. The workshop is to the left of the driveway in this elevation.

http://smilesrus.com/lot/IMG_0349-enhanced.jpg

Sounds like I need something in the neighborhood of 100A service minimum.

[John Schreiber]

If the workshop is going to be connected by a "porte coche," then perhaps you should be planning for a studio rather than a shop. To get to a workshop, you should go through mud, or at best a covered walkway.:D:D:D:D

Just funning you. I've never heard of a porte coche before. Congratulations on the new land, house, shop and the whole adventure.

[Steve Kohn]

I was having a remodel done and upgraded my main panel to 200 amps. I had a 100 amp subpanel put into the shop. I run most major tools on 220V.

However, I do not have air conditioning. I also am a hobbiest, running a one man show.

[Glen Blanchard]

If the workshop is going to be connected by a "porte coche," then perhaps you should be planning for a studio rather than a shop. To get to a workshop, you should go through mud, or at best a covered walkway.:D:D:D:D

Just funning you. I've never heard of a porte coche before. Congratulations on the new land, house, shop and the whole adventure.

They are fairly common down here in Texas. They allow for "hidden" garage doors, as the driveway passes through the porte coche to get to the garages. Don't think my wife would be too keen on the mud idea. :D

[Alan Greene]

I would go with Jim's advice and put in the 100 amp panel but have the wire feed in rated for 200 amp. I f you ever need it then it is available. The cost to rerun the feed would be exorbitant. It could also be used as a selling point in the future, if you ever sell (say to someone who welds or does automotive for a hobby), to someone who may need the extra power. When I had my house appraised the inspector mentioned that the sub panel rating would positively affected the price.

[Tom Maple]

Glen,
Depending on the distance from your main distribution panel to the sub panel in your shop, the cost difference for the upgrade in wire from 100 amp to 150 or 200 amp will cost more than the panel itself.
If you go with the heavier supply wire now with the idea of upgrading the box later, you're not saving much money. If you go with heavy wire now just get the 200 amp box now, it will add less than $50 to the cost.
By the way, you have a beautiful plan. I'm sure many of us are envious.
Tom

[Kyle Kraft]

Amen, Tom. If you're running 200A feeder, it is senseless to install a 100A box. Spend the extra $20 and put in a 200A.

[Cliff Rohrabacher]

Will also have central HVAC,

Them's fight'en words.

[Jim Becker]

You can put in 200 amp rated wire and a 200 amp rated sub-panel and still supply it with 100 or 150 amps if that's all you require. The cost difference is minimal over time to put in the infrastructure that can be goosed upward later if needed. In fact, I'm about to actually de-rate my 200 amp supply to the shop building because our priorities have changed from finishing living/office space upstairs there with HVAC added to building an 1850 sq ft addition on the house that will include another HVAC system. I don't need 200 amps for the shop building at this point because of this change, but will require more of the 400 amp capacity to the property for the addition. The electrician is mapping things out accordingly.