Shop 240 volt wiring

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MRDucks2

MRDucks2

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Quick and easy (OK, call it 220 if it makes you feel better):
When wiring 240 volt for your woodworking/hobby shop did you go 2 wire or 3 wire?
I am installing 2 different circuits of 240 so I guess I could do 1 of each, but amongst our tools it seems 2 wire is pretty standard.

If you do not get the basis of the question, that's OK, don't feel obligated to try and clarify.

Thanks for the feedback!
 
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Most 240 volt motors are 3 wire, 2 hots and a ground. You can probably use either 10-2 for 30 amp or 12-2 for 20 amp. You just have to mark the white wire with red electrical tape at both ends to indicate it is hot.
 
It depends completely on what tools you are using, what their requirements are and what plugs they have.

240V tools with a 3 prong plug are 2 hots and a ground, but with 4 prongs are 2 hots, a neutral and a ground. Some 240V tools/appliances have a 120V component and they need the neutral since either of the 2 hots to neutral is 120V. It is unsafe and against code to use the ground for this purpose. If it were me, I'd get the 3 conductor (3+bare ground) and run that. Then you are covered. If your tools/appliance outlet doesn't need the neutral, put a wire nut on it and leave it in the box behind the outlet. Someday you may be glad you did it this way.

Disclaimer: I am NOT an electrician, I never played one on TV and I did not stay at a Holiday Inn Express last night.
 
I am an electrician and played one for 43 years. I will agree with Dave on this pull the 3 wire for future use if not needed now. Never know what happens down the road but you will be covered. Make sure you use the correct size wire though. You can go larger but not smaller as long as you use proper sized breaker.
 
David, I also second the David B and John recommendation for the 3 plus ground. I went this route when I added some 220/240 to my garage workshop in case I or a future homeowner ever wanted to add EV charging. This may not be applicable to your workshop depending on your setup but given the marginal extra cost vs. mess of trying to add in the future, it seems like cheep insurance to me...
 
David350 said:
David, I also second the David B and John recommendation for the 3 plus ground. I went this route when I added some 220/240 to my garage workshop in case I or a future homeowner ever wanted to add EV charging. This may not be applicable to your workshop depending on your setup but given the marginal extra cost vs. mess of trying to add in the future, it seems like cheep insurance to me...
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If you are thinking you might want the circuit for EV charging, make sure you look into the requirements for that before purchasing and installing wire and/or raceway.

For example, if you run Romex, while rated at 90 deg C, the code limits you to the ampacity of a 60 deg C conductor (read the code if you want to know why). My EV charging connector was very specific about running 90 deg C wire. This is most likely because EV chargers when charging are running at very high current for extended time, where as most power tools don't behave this way. In my case, 60 amp breaker, 20% safety factor (automatically programmed into EV/Connector) will draw 48 amps continuously during a charge which could be 30 mintues or it could be 5 hours straight. Short version, for my charger connection, Romex wasn't recommended. I ran MC cable (metal clad) which contained individually 90 deg C rated THHN conductors so I know I'm good.

Sorry if this is only confusing the issue, but I wanted to bring it up because incorrectly installed EV charging equipment is dangerous.

Short Version: If you aren't an electrician and you are thinking you might use this circuit for EV charging, hire a professional.
 
I read hobby shop or workshop which I started thinking basement shop. now if this is a shed or outdoor structure than other codes come into play as well. But if hobby shop is basement than no need for charging station codes needed. Distance plays huge parts in charging stations as well as any outlet from a panel. Charging stations codes can vary state to state also. along with UL codes. I see in the future those codes will be changing as more and more homes as well as businesses take on the ability to charge electric vehicles.
 
David, I agree and I installed it with a Hubbell outlet rated specifically for EV charging, another commonly overlooked item as the cheap ones at the home center cant handle hours of continuous current...
 
Thanks gentlemen. this has been kicking around in my head for "awhile". I have already pulled 10/3 for the exact reason list David & David. I don't have any 220, 221 whatever it takes tools, but always think about building for success instead of failure.
 
Swede3001 said:
Thanks gentlemen. this has been kicking around in my head for "awhile". I have already pulled 10/3 for the exact reason list David & David. I don't have any 220, 221 whatever it takes tools, but always think about building for success instead of failure.
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There are many tools that have the capability to be converted to 220V by rewiring the motor. By the way Voltage is not always the same throughout the day. Put a meter on an outlet and watch it fluctuate. Time of the year means alot especially if power companies cut back on power. Also depends where you are on the chain line. I laugh when people talk 240 to 220 or 110 to 120Volts. :)
 
jttheclockman said:
There are many tools that have the capability to be converted to 220V by rewiring the motor. By the way Voltage is not always the same throughout the day. Put a meter on an outlet and watch it fluctuate. Time of the year means alot especially if power companies cut back on power. Also depends where you are on the chain line. I laugh when people talk 240 to 220 or 110 to 120Volts. :)
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This afternoon, while having a couple of young electricians pull the 4/0 4/0 4/0 2/0 feed from the disconnect at the meter to the shop through 2 inch conduit, I noticed the smart meter was showing 250 volts.
 
MRDucks2 said:
This afternoon, while having a couple of young electricians pull the 4/0 4/0 4/0 2/0 feed from the disconnect at the meter to the shop through 2 inch conduit, I noticed the smart meter was showing 250 volts.
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It can vary all times of the day for many reasons. Use a digital volt meter and plug into the same out various times during a day and night and see how much difference happens. Our appliances and tools are built with a Power factor in them so they can handle fluctuations.
 
jttheclockman said:
It can vary all times of the day for many reasons. Use a digital volt meter and plug into the same out various times during a day and night and see how much difference happens. Our appliances and tools are built with a Power factor in them so they can handle fluctuations.
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True - but there is a limit. I live at a NJ shore area where the population varies really widely depending on weather and season. The power company here does a good job at trying to keep power within a reasonable level, but we had a recent failure of a capacitor put on the power lines by the power company to help regulate the voltage swings - it blew up! Our power dropped down to sub 100 volts for an extended period while the power guys did diagnostics and adjustments to the feeds. Most of my neighbors lost washing machines, dryers, microwaves, and a few lost their furnace controllers due to the extreme low voltage situation. Power company offered payments to replace stuff if you filed a claim, but most didn't cover most of the damages. I have a Nova DVR lathe and was advised by their support people to keep it unplugged at any time when it is sitting idle - the power variations tend to fry the controller circuit. Good advice for anyone else with a variable speed lathe.
 
NJturner said:
True - but there is a limit. I live at a NJ shore area where the population varies really widely depending on weather and season. The power company here does a good job at trying to keep power within a reasonable level, but we had a recent failure of a capacitor put on the power lines by the power company to help regulate the voltage swings - it blew up! Our power dropped down to sub 100 volts for an extended period while the power guys did diagnostics and adjustments to the feeds. Most of my neighbors lost washing machines, dryers, microwaves, and a few lost their furnace controllers due to the extreme low voltage situation. Power company offered payments to replace stuff if you filed a claim, but most didn't cover most of the damages. I have a Nova DVR lathe and was advised by their support people to keep it unplugged at any time when it is sitting idle - the power variations tend to fry the controller circuit. Good advice for anyone else with a variable speed lathe.
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That is very true. You are talking extreme cases. The same can be said for voltages going too high. Lose a phase and it can cause all kinds of problems too. Today's electronics are subject to power fluctuations and can cause damage. Lightening strikes can cause damage as we all know.
 
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