Any 240v woodworking equipment need a neutral?

[Andy Dingley]

Same as anywhere else. It's not the voltage, it's the number of phases.

If you use single phase (and "domestic" always does) then you need a neutral. This isn't because you "need" it as a consumer, just because it's the convenient way to tap a supply transformer for a single phase output.

If you use multi-phase (i.e. three phase), then you don't need and don't use a neutral. There's just little point to it.

If you choose too low a consumption voltage in designing a system-wide standard (i.e. 110V) then it becomes necessary to also provide a high "high power domestic" feed of twice this, hacked together by using opposing phases of a two phase supply. You don't even need neutral here either. It can be useful though for loads that are easily split in two (i.e. heating elements) and is naturally provided if the "double voltage" system is already providing a neutral connection to the supply transformer's centre tap.

[Doug Miller]

No, actually, if it's the grounded conductor, it's the neutral conductor, regardless.

[Doug Miller]

In much of the rest of the world, yes, that's right. Their 240V circuits are wired analogously to our 120V circuits, just at a higher voltage.

[Andy Dingley]

No they're not! Only in TN-C systems. There are several other ways to arrange things, and the others are just as popular.

[Doug Miller]

So here's a question for any electrical inspectors that may be listening in: Code requires that any wire so marked must be "permanently reidentified....by painting or other effective means". Is taping "permanent" or "effective" enough? I usually use a permanent marker.

[Frank Boettcher]

If there are no 120 accessory items on the machine.

However, as one who is at this very moment lamenting the fact that he did not plan ahead and pull what he should have pulled when he originally built his shop, and now to expand it will have to pull again, knowing it would have been just as easy and not much more cost to pull more than one would need, my advice in that area should be predictable (as I slap my head in dismay).

But:

You do not need a grounded conductor if you do not have any requirement for it on the machine.

You DO need a grounding conductor. You're health and well being might require it. Additionally, you will negate the work of that fine individual(s) at the end of the assembly line who painstakenly checked each and every machine for complete ground continuity before it was shipped to you.

In my area, the only requirement for a licensed electrician is at a service entrance set, and no permit is required to run a circuit inside your house.

I don't know about your insurance policy, but mine does not have a clause where I promise to hire an electrician, disallowing the policy if I don't.

Frank

[Frank Boettcher]

A troll sir, meant to confuse.

A nuetral is a grounded conductor, required on that drier because it has 120V circuits within it.

A ground is a grounding conductor, only used as a path back to ground from any conducting point on your appliance, tool, etc. in the event you have an electrical fault. It provides a path that, I'm sure you will agree, is a better path to ground than through your carcass.

Frank

[Doug Miller]

Explain that a little further, if you would please. Here in the US, 3-phase power *does* have a neutral. The voltage is (typically) 208V phase-to-phase, and 120V phase-to-neutral.

[Frank Boettcher]

Not true.

[Jack]

Toller, If it's only a 240v motor the 10-2 is correct. Let us know what machine you are trying to connect. Are you connecting to a main panel or a sub panel?

[Scott Lurndal]

If he were to do it "right" the first time, he'd use 10/2 w/g.

If you were to wire a separate 110v outlet from this (instead of using a 4-pole receptacle), you'd be in violation of code, since the breakers are handle-tied (which would prevent one from being able to disconnect the 110v circuit without also disconnecting the

220v circuit).

While this is generally true; doing to the specific requirements of your jurisdiction is better.

scott

[Andy Dingley]

That's not a 3-phase system, it's a combination of 3-phase and single phase. Only the single phase component needs the neutral to supply power, but because it's also bonded to the local earth it's supplied as well. It's sometimes used for the provision of separate heating elements on each phase, also with electrode boilers so as to limit potential difference between the water and earth.

[Doug Miller]

Sorry, he's right about that, and you're mistaken. There's nothing in the Code that prohibits that.

[Doug Miller]

How do you figure that? The three phases are tapped off a rotary generator at the power plant, 120 degrees apart, with the neutral as earth ground. Any one of the three phases can be used separately, of course, but there's no "combination" present.

Might be different in the UK, but there isn't a separate "single phase component" in North American three-phase power distribution -- 120V devices are powered by using any one of the three phases, and a neutral which is bonded to earth ground.

208V devices use any two of the three phase conductors, or all three, and no neutral.

[Andy Dingley]

That's what I'm telling you. Both systems are wired through similar cabling, but the neutral only gets used when it's supplying a simgle phase device.

And the "208V 2 out of 3 phases" unbalanced systems are an abomination unto the hallowed memory of Tesla.

[Mike Richardson]

Well, hehe - whilst the subect is VERY serious - I truly needed that giggle.

Of course - key point - if you have to ask - u probably don't get the sarcasm either.

I am NEARLY complete on my new shed/shop - whats the one thing I didn't touch...? zzzzt.

:-)

[Mike Marlow]

Well - you know what they say - you just never know when you might want to hook a clothes dryer up to that cabinet saw...

[Mike Marlow]

Yes - your bad on this one. The OP stated 10/2. Can you even buy 10/2 without a ground anymore? Swing's story was about people on his job site, not a reference to anything the OP posted.

[Mike Marlow]

I haven't used a jointer since the 60's. Then I learnt how to roll my own...

[Mike Marlow]

Ah.... my favorite BS stuff. Throw some fear, uncertainty and doubt into something when proper knowledge fails.

It's a purpose device. Who cares what may go in there in 5 years? Wire that in at that time. Unless it's a clothes dryer it won't likely need a neutral anyway.

And... who is liable for damages if there is a house fire? Here it comes... THE INSURANCE COMPANY. Please explain how the home owner is going to liable for wiring a saw with 10/2 with a ground? He's not. Even if he wires it wrong and sells the house, he's not liable. Geeze...