Next installment in my continuing series of posts about setting up a back yard workshop …
In this thread I figured out how to get started with closing in my shed and turning it into a proper workshop. Now I’ve got an insulated attic / ceiling, and eventually I’ll be doing the same to the walls.
Before that though, I want to re-do the wiring! I wanted to solicit some suggestions and learn from some “If I had only done XYZ first …” comments.
To start with
The shed is 10×20 with a (basically) 8 foot ceiling. Right now it has its own subpanel box, which has (IIRC) 6 slots, 4 of which are filled with 20 amp breakers. Right now, since the original wiring was done pretty sloppily, the entire shed runs off just ONE of those breakers—the rest of the subpanel is not being used. So obviously that’s dumb, I’m going to run separate circuits to utilize multiple breakers.
I still need to check on the service coming out from the house to the shed. Based on my initial research, it looks like I really need to take an inventory of what the maximum amperage that I plan to draw at one time within the workshop, and make sure the main service is AT LEAST that large, if not 1.2x or 1.5x that number. Is that about right?
Here’s the start of that “amperage inventory” at the moment:
• Table saw will get its own dedicated circuit—probably will be R4512 which draws 13 amps
• Several smaller stationary tools (shop vac, router, miter saw) draw between 11 and 15 amps apiece, so I’ll need at least 1 or 2 separate general plug-in circuits (aside from table saw) to make sure I can run my shop vac / dust collection at the same time as these
• Ceiling lights are LED and there’s a small powered duct vent in the attic—I imagine those can all be on one circuit
• I have a couple of exterior outlets that may be used for an electric tiller or electric chipper—those are both 11 or 12 amps so I presume they would want to be on their own circuit as well
• I have a window unit A/C which of course needs it’s own circuit
The largest concurrent usage I can imagine is:
- Several LED lights and attic fan (let’s be conservative and say 5A)
- Shop vac (12A)
- Miter saw (15A)
- Window unit A/C (6A)
- 1 or 2 cordless battery chargers (~2A ?)
... I can’t imagine running more than that, concurrently—but maybe I am naive about how my hobby will grow. So a total of about 40A at a time. That seems like not much to ask. Thoughts?
Meanwhile as for planning out circuits …
I need some confirmation that my thinking is on the right track here. The list above suggests I might have something like the following circuits
1) Ceiling / attic circuit for lights and attic fan
2) Dedicated circuit for window A/C
3) Dedicated circuit for using one large tool at a time—miter saw or table saw, for instance
4) Second general plug-in circuit so I can run the shop vac at the same time as using #3; will also be used for smaller handheld power tools
5) Dedicated circuit for exterior outlets
I’m thinking #4 might actually need to be two separate circuits, since (even though it’s a small shop) I’m likely to add something like a drill press, bench grinder, etc. in the future.
Overall am I headed in the right direction here?
What have I missed?
Aside from the general amperage approach I’m using to plan out circuits, what else should I think about? What else did you WISH you built in capacity for, or WHERE to put receptacles earlier, that I ought to know about?
Eager for your thoughts. Thanks!