I am in the process of converting my Jet contractor saw to 240. I may be wrong, but in the past I have seen this done using 12/2 romex (2 hot plus 1 ground) using the white neutral as a hot.
My father-in-law says that I need to use 12/3 for this application. (2 hot, 1 neutral, plus 1 ground) Is he correct? He has a background in electricity, and I could tell that he wanted to help with this project, but I think he may be confused.
Any help is appreciated.
in vino veritas
Replies
You are right.
You don't need a neutral for something like a pure 240 volt motor.
However some people do run the 3rd wire for a neutral, Just In Case. One thing that people sometime do is also install a 120 receptacle for a power feeder.
Just remember that if you use the 2 wire to put a piece of black tape on each end of the white wire to indicate that it is now a hot wire.
Depends. As I understand it the basic saw only runs a dual voltage motor at either 120v or 240v. As far as the motor goes if you switch to 240v you no have no need for 120v and so you can do without a neutral. Simple.
But possibly too simple. If the unit has any controls for a vacuum system not fed from other sources, variable speed controls, power feed devices or others that demand 120v to function properly you need a neutral to supply the necessary voltage.
I suspect that the later case is unlikely, fairly rare, but not entirely unknown on higher end or heavily accessorized power tools.
Your friend claims the saw needs a neutral. Ask him what in or on the saw, presently or in the future, might require 120v. Perhaps he sees something we are missing.
Edited to add last block of text.
Edited 10/3/2005 6:18 pm ET by 4Lorn1
Sometimes a device (probably not a table saw, but maybe a bandsaw) has a light that needs 120V. A simple solution, if it's a standard Edison bulb, is to replace the bulb with a 240V bulb. (If you do this, be sure to mark the fixture plainly as needing a 240V bulb.)
Thank you all for the help. Looks like I'll go ahead and run the 12/3 simply in case I get any other equipment in the future that may require the neutral to be present.
in vino veritas