Shop wiring advice

[91bird]

Yesterday a friend and I built a small room in my basement for a workshop. There will be an 8ft long bench with 3 110VAC outlets spaced a couple feet apart above the bench for using at the bench and 3 more outlets below those 3 that will be ~18" above the floor. The first outlet for the outlets at the bench will be a GFI that feeds the rest of the outlets at the bench.

At the wall adjacent to the bench I will most likely put an X3 mill and on the wall behind the 8ft bench will be a lathe like the 10x22" Grizzly G0602. At some point the Mill will be converted to CNC.

My question is what would be the best approach for wiring for the mill and lathe? Would one 20A circuit be enough for the bench outlets, mill, and lathe? The problem I see is if the mill is converted to CNC and I want to turn something on the lathe the circuit would most likely pop. I don't think there is enough space in my breaker panel to run 3 separate lines.

I think I can pull in the power for lighting from another circuit.

Any help you can give would be very helpful so I can wire it right the first time and not have to redo the sheet rock in a few months. Are there some web pages I could visit where someone has some info on home machine shop wiring?

[Al_The_Man]

Generally in high use areas like a workshop etc, the outlets are run as in a Kitchen, which is another high use area.
Two 120v circuits are run off adjacent breakers that straddle the 240 so that you have two 120 & Neutral, when the outlets are wired, the link between the hot top and bottom outlets are clipped, so that top is one circuit and the bottom another in order to balance the load.
Motor start/stopping produces a high incidence of inrush, which if used in conjunction with other loads, will cause nuisance tripping.
Also consider if you CNC the mill, you may want to put a 3 phase motor and VFD on the spindle, which requires 240v.
Or even going with a 190VDC spindle requires a 240v drive.
Al.

[Geof]

It is possible the first thing you should read is your home insurance policy. You might find that they have an escape clause if a fire is started by DIY wiring. Sometimes the safest this is to bring in the licensed electrician.

[Al_The_Man]

Originally Posted by Geof It is possible the first thing you should read is your home insurance policy. You might find that they have an escape clause if a fire is started by DIY wiring. Sometimes the safest this is to bring in the licensed electrician.

I am not sure about the US, but most Canadian cities will allow the HomeOwner to do his own wiring/installation as long as it passes a final inspection by the local Utility. Or you can do it under the observing eye of a qualified licensed Electrician.
Al.

[Geof]

Originally Posted by Al_The_Man I am not sure about the US, but most Canadian cities will allow the HomeOwner to do his own wiring/installation as long as it passes a final inspection by the local Utility. Or you can do it under the observing eye of a qualified licensed Electrician. Al.

Correct, but insurance companies sometimes have their own picky little clauses. It is better to find them, or confirm they do not exist, beore they are needed.

[Al_The_Man]

... but it was already like that when I moved in!

[TOTALLYRC]

In the 10 or so US cities that I have done work in, the home owner is allowed to do his own electrical work as long as it passes inspection by the local building inspector.

What I used to do before I learned how to do it myself was to find a liscensed electrician that I or somebody else knew and by him dinner or a case of beer for a consultation.
Make it clear up front that you only want him to tell you how to do it and don't lead him on thinking he will get the job. A $50 dinner goes a long way in getting what you want.

I used to do whole renovations and he would just show up on inspection day to walk around with the inspector. He loved to make a days pay for doing next to nothing and I saved a couple grand on the larger jobs. Of course he watched us like a hawk untill he realised we were doing it right.

[91bird]

I will have to have an electrician or inspector come in and look it over. Most likely I will have an electrician come in and hook the power up to the breaker panel so if something does happen I will have documentation saying it was done right. I am an Electrical Engineer so I would hope the insurance company doesn't have a problem with it.

Hearing/reading the experiences of people who have wired their shop and after using it wish they had done something different with the wiring is very valuable.

[TOTALLYRC]

Originally Posted by 91bird I will have to have an electrician or inspector come in and look it over. Most likely I will have an electrician come in and hook the power up to the breaker panel so if something does happen I will have documentation saying it was done right. I am an Electrical Engineer so I would hope the insurance company doesn't have a problem with it. Hearing/reading the experiences of people who have wired their shop and after using it wish they had done something different with the wiring is very valuable.

I heard a great quote and it goes something like this.

"Discretion is the greatest part of valor"

As an EE I am sure that it is well within you capabilities, but who wants to get a check for $0 because you did it your self and the Insurance company didn't like it?

[LaserImage]

What about wiring in a sub-panel just for the shop? You can do it with some 10 guage wire and get at least 30 amps.

Gary

[91bird]

Originally Posted by LaserImage What about wiring in a sub-panel just for the shop? You can do it with some 10 guage wire and get at least 30 amps. Gary

That is one option. I believe it would have to be outside the shop if following the current 2008 national electric codes. I think there is a statement in the codes that a breaker panel can't be in a room with combustable materials but I'm not sure about that one.

[Dualkit]

I completely wired my own shop and have done those of others. The only thing
I feel I did wrong was get a permit on a panel upgrade. NEVER again!!! Most
local codes in my state are way over-kill for grounding requirements and other things. The inspectors are not even consistent and know way less about electricity than your average car salesman, they are just trained on what to look for and that's it. I asked "why" on a few silly regulations and they could not
even give me a logical explanation. For what you are doing I would suggest at
least a 40 amp sub-panel preferably 60 amp. Your average mill and lathe can
suck 10 each and that is without running a phase converter. Bench grinders
and buffers have high inrush currents up to 15 amps even on small models.
What you do will also depend on if you own the property. If done properly no one will ask if it was permitted or not when it comes time to sell.