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-   -   woodshop wiring questions (http://www.diychatroom.com/f18/woodshop-wiring-questions-18700/)

baldeagle390 03-18-2008 09:26 PM

woodshop wiring questions
 
Hi,
Just found this forum. I did not see answers to my questions but I've only been a member for an hour.

I am building a woodshop in my pole barn. I recieved an electrical permit (Oak Creek, WI allows us to pull our own permits) to install a subpanel which will run 50 ft. from a 200 amp existing service to the area that will be the shop. (I will be pouring a concrete floor and I want the 1 1/2" conduit to run under the concrete. I am using #2 URD with a #8 cu ground [I know about seperating the common & ground etc.].) I was going to buy a new main lug panel but I was given a 100 amp main breaker panel in good shape along with a number of breakers. Can I still use a 100 amp breaker in the main panel, or must it be less amps than the breaker in the subpanel?

Question 2. Before I pour concrete, I was planning to run 1 1/2" conduit (overkill?) from the subpanel, to a central location to feed a planner, jointer and table saw (all 220v). I was told that the conduit should transition to metal through the concrete floor. I was also told that there should be a "dummy" metal post through the concrete to the box, for strength I suppose. Is that "dummy" post code and if not, is it necessary?

If anyone has done any shop wiring under a concrete floor, I would love to hear from you. I only have one shot to get this right. Thanks

goose134 03-18-2008 10:49 PM

I believe that you will need a disconnect for the panel in the shop. It should be rated for the full load of the panel (100 A) .

I think 1 1/2 is a great idea. No one ever complained about having too much room in conduit.

As for the floor penetrations, yes the boxes need to be supported. If you were to use galvanized rigid conduit and hit a box with two pipes coming out of the cement this should provide you with the support to satisfy code. For example, come out with a 3/4 from the panel to the planer, one from the planer to the jointer, out of the jointer and into a wall box.

If that isn't what you want, you could bang a piece of unistrut in the ground and let them pour around it. You could easily mount the box to that.

Good luck with the shop. Starting from scratch sounds like a dream come true!

220/221 03-19-2008 12:08 AM

Quote:

Can I still use a 100 amp breaker in the main panel, or must it be less amps than the breaker in the subpanel?

You can use it. The 100 amp main protects the bus.

Quote:

I was planning to run 1 1/2" conduit (overkill?
Conduit can (almost) never be too big :thumbup:

As far as the jbox, you might want to consider driving a copuple pieces of strut or tubing to mount your box to. If you are planning a table, cabinet or any other structure close to the equipment you could mount the jb on it.


If you want a little slack to work with, stub up flush at finished floor with a female adapter and (after concrete) flex up to your jb. You could do this in as many areas as you like for future points of power.

hpp58 03-19-2008 07:33 AM

Watch callin your project a "wood shop".
A true wood shop is a class 3 hazardous location.
You might want to call it a "hobby shop"

jcalvin 03-19-2008 12:49 PM

Quote:

Originally Posted by hpp58 (Post 109070)
Watch callin your project a "wood shop".
A true wood shop is a class 3 hazardous location.
You might want to call it a "hobby shop"

I second that.

baldeagle390 03-20-2008 09:52 PM

Thanks goose and 220/221. Kind of what I was thinking of doing. My neighbor was supposed to come over tomorrow with the mini-excavator and get started, but the ground is still frozen and 8-10" of snow on the way. :mad: Sorry about the late reply. They started blocking this site where I work. What do you guys talk about anyway..hmmmmm?


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