Should I separate my shop to its own sub panel?

dwg426

New User
Doug
H Everyone,

I have a 30x60 building with its own 200 amp power that was upgraded from a 40 amp fuse panel. Lots of kids and grandkids. The front 25x30 area is pretty much a rec/party area. The power feed is in the front of the building in the rec area. Im getting ready to rewire the building. Im thinking I would like the shop area to have its own 50-60 amp sub panel to the shop area so that I can turn off and lock out all the wood shop power. What are your guys thoughts and hints? How many amps should I run? Seems one single run of #6 0r #4 wire for 30 feet to a sub panel vs 6-8 runs of #12 wire from. The main panel to back of hop is pretty much a wash. I want to plan a total of 2-3 people working in the shop at the same time.

I have two large dust collectors, large bandsaw, table saw, mitre saw, scroll saw, jointer and planer.
 

McRabbet

Rob
Corporate Member
It would seem more likely that the 35 x 30 foot workshop section would need the majority of the ampacity from your panel, rather than the rec/party section. I would think it might be better to move the 200 Amp service to the woodshop and put a subpanel of 40-60 amps in the rec/party area. You will need more than 50-60 amps in the workshop section.
 

Oka

Oka
Corporate Member
Short answer .......... Yes, and if you have controllers on your equipment (digital, CNC, etc, Then you should also have a dedicated ground. In this case a 10-ft ground rod pounded into the ground that will provide additional grounding.

You can look up a voltage demand calculator, ......... or you can just look at all the loads add them up and multiply by 1.25, that will get you what size panel main you should have and then, size the wire accordingly.

Me, I set up the Planer, Table saw and lathe all on their own circuit. The Band saw and Drill press are on 1 circuit together, the Belt/Disc sander and the Joiner are on their own. I have one circuit that has 3 outlets and my dust collector is on that, and I have 2 other circuits for other plugs.

The Planer, Lathe and Table saw all pull about 15 amps each, so x 1.25 = 18.75 amp start demand or 20 amp breaker. Everything else is roughly 6-8 amp for the other tools. Super unlikely to use the Band saw and Drill press at the same time ergo 1 circuit. those are all 15 amp. When getting close to a breaker rating it is best to round up.

Hope that helps
 

Mike Davis

Mike
Corporate Member
My single car garage shop has its own 50 amp panel. I work alone or with one other person.
Most I would have is the lathe and dust collector or saw and collector.

If I had 4 people working at same time I would want each machine on separate breaker and one for dust.

I'd say at 100 amps for your shop. As Rob said if possible move the 200 to the shop and run 50 to the front for the rec area.
 

jlwest

Jeff
Corporate Member
I am not sure why you want another panel. You can turn off all your circuits from the existing main via the breakers. This assumes your shop has it's own circuits that are not shared with your rec area.
 

Gofor

Mark
Corporate Member
For one person, 60 amp would be fine, but for three that might be a little sparse, especially if both dust collectors are running at the same time as three of the big power tools. Figuring 15A for each comes to 75A, and with start-up draw as the three power tools are cycled on and off, you are going to far exceed 60A.
 

Dreuxgrad

Ed
Senior User
When I did the addition to the house, I had to move the feed because it was in would be under the projected slab.
That prompted the possibility of extra panels for the shop. Ended up with several additional panels, one for the original shop, one for the utility room for a dust collector, and one for the wood shop-which had more amperage than the existing original panel with the replacement feed. About fifty percent more, if my memory is correct. So long story short-make your shop the main, and feed a sub for the gathering room.
 

Oka

Oka
Corporate Member
Cleaner power is the goal. Assuming you have a 200 amp main, I would put in a 1000 amp sub. The power to that panel will be cleaner than running a bunch of smaller lines from a longer point source, It is always better to bring the demand to a local distribution point and then branch from there.

Old time electricians would use this "back of the envelope" method to run sub panels......... if you have for example a 100 amp service main then the next sub panel should not exceed 80 amps as long as you do not exceed 100 amps in the main service. But, this was rarely adhered to. Bear in mind that not all units are demanding at the same time, but because of common sense and safety, with electricity, the rule is to base on most demand possible not most demand actually used. This provides a bigger safety factor.

I will provide a separate post later today after work where one of my "journeymen workers" over demanded a line and nearly set the building on fire...... SMH
 

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