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View Full Version : Installing a Subpanel


JimV
Oct 23, 2006, 05:14 PM
I'm setting up a woodshop in my garage and want to install a subpanel to run my equipment off (it's going to be right next to the main). I'm starting from scratch, knowing extremely little about how to accomplish this. What sort of box do I need to buy, how do I size the breaker that will feed the sub from the main, etc. My main is full, so what I've been advised to do is move the dryer circuit to the subpanel... does that sound like good advise? I can see that the most things running at one time will be the dryer, a 220 dust collector, a 220 saw or sander and the fluorescent lighting. Is that enough info to get us at least started on this project? Thanks in advance.

Jim

tkrussell
Oct 23, 2006, 05:31 PM
Is there any chance your main panel can handle half size or tandem breakers, which are breakers that allow two breakers in place of one full size unit?

Many panels allow this, unless your panel is 42 circuits already. See if there is any information on the label on the inside of the door. May be a little cryptic, so get back with a picture or model number of your panel if needed.

For only two or three power tools, this may be easier and better.

To size the panel and feeder I would like to have the wattage or hp of the tools, and how many would need to run at once. If a subpanel does go in, then relocate two low load circuits to make space for the subpanel feeder breaker. This will leave more capacity in the sub.

JimV
Oct 23, 2006, 09:09 PM
My main panel can take half size breakers, but I would really like to isolate my shop from the rest of the house.
The major equipment that I have is as follows:
Table Saw - 3hp, 220V, 18A
Edge Sander - 1 1/2 hp, 220V, 8A
Bandsaw - 2hp, 220V, 14A
Cyclone Dust Collector - 2hp, 220V, 12.5A
Lathe - 110V, 75kW
The cyclone will be running almost all the time, along with one of the other tools, or smaller hand tools such as a drill, router, etc.. It really needs to have its own circuit, separate from anything else.
Along with that I'd like to have at least 2 other 220V circuits for all the other equipment.
I also want to outfit the area with lots of 110V plugins, as well as wiring in the shops lights on their own circuit.

tkrussell
Oct 24, 2006, 07:18 AM
A 60 amp subfeeder to a new panel would be fine, leaving some room for expansion.Still, to make room in the main panel, move two low load cirucits to the new panel to make room for a 2 pole 60 amp breaker.

Leave large load circuits in the main panel.

Connect the two panels with a 2" nipple to run the feeder and the branch circuits from one panel to the other. Will need 3-#6 for the two hots and one neutral, one #10 mim for the equipment ground. Be sure to isolate the neutral bar in the subpanel and only have neutral wires connet to it. Install an equipment ground bar bolted into the new panel for any green or bare grounds.

In the main panel, note if the neutral is isolated or connected to the equipment grounds, and follow suit to connect the new panel neutral and ground to the main panel.

Hope this helps and makes sense.