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I just recently built a new shop. I had it wired for 110V and 220V. I have been thinking of upgrading to a better table saw and noticed a few that say they are 230V or 240V, does that mean I need to change my 220V? or will it still work on my 220V ?

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In general, the designation 220 VAC (volts alternating current) is a nominal value. The actual value is in a range, depending on your utility, your distance from the transformer that serves your house, and other factors including time of day and nearby loads.

The short story is that your nominally 220 VAC outlets will work just fine with a motor rated for 240 VAC. If you check the actual voltage at your outlets, there's a very good chance you'll find them to provide between 230 and 250 VAC anyway (observe all necessary precautions for measuring line voltage and don't attempt it if you're not confident with that or your measuring equipment).

In any case, I don't expect you have a choice. 220 and 240 wiring is not different; it's just a case of what you get where you are located.

One thing that is markedly different though is 240 VAC 3-phase (as opposed to single phase, which is almost certainly what you have). Industrial motors use 3-phase power because it's more efficient and provides smoother power. 3-phase is not commonly available in residential areas. The wiring for that would be different, but the common use of varying nominal terms like 220 and 240 would also apply there; different working names for the same thing.

A 3-phase motor will not work with single-phase power (although it's a little more complicated than just "doesn't work").

  • If you have a couple of extra slots in your breaker box, I believe a competent/certified electrician can make a 3-phase circuit out of a single-phase feed for you (if OP had to ask this question, he's not competent enough. It's OK, neither am I). Industrial grade 3-phase table saws are probably going to be a bit pricier than even a high quality single-phase saw, though, so you may want to look into that before you start calling electricians. You could ask about the 1- to 3-phase at Home Improvement or Electrical Engineering - that should be on-topic at either site (HI more likely, though). – FreeMan Sep 13 '17 at 20:27
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    @FreeMan: A 3-phase supply cannot be made out of a single-phase feed by configuring the wiring differently. 3-phase power can be synthesized using a variable frequency drive unit (VFD) or a rotary phase converter. Neither of these solutions produce three-phase power quite the same as that from a utility feed and each is appropriate only for certain applications. Neither of them are small enough to fit in your breaker panel. However, they are both possible viable options for getting 3-phase in your shop so you can use an industrial motor for a power tool. – scanny Sep 14 '17 at 19:53

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