Single Pole switch for 240 circuits

[dnwong]

Can I use a single pole toggle switch to turn power off to an 240v outlet. If the switch was co-located near the switch I would have used a Double Pole. However, I only have one 12-2 wire going from the toggle switch to outlet where the power come to the outlet first.

I just want to remotely shut off the power going to the compressor, I would only be switch 120v (half) of the total month required.

 

[94EG8]

No you can't just switch one leg.

 

[Cmreschke]

Uses as a means of disconnect? No. Used as a switch to shut it off plus you have a means of disconnect for servicing, sure I don't see why not. A 240 volt photocell does the same thing, it only breaks one of the two lines.

 

[wyliesdiesels]

What is the HP rating on the compressor?

 

[Dick in Wisconsin]

Isn't this where a 120volt switch would control a relay that would actually switch the 240volt on and off?

 

[Speedy Petey]

No you can't just switch one leg.

Code citation? Or is this another case of "I've always been told..." ?

 

[bandaidmd]

Uses as a means of disconnect? No. Used as a switch to shut it off plus you have a means of disconnect for servicing, sure I don't see why not. A 240 volt photocell does the same thing, it only breaks one of the two lines.

only having one leg going to the compressor by switching off the other one should prevent it from running but it cant serve as a service disconnect because you still have power on the non switched leg.

 

[Norcal]

Code citation? Or is this another case of "I've always been told..." ?

Nahh, just another quotation from the Urban Legend Code.

 

[Dagny]

motor ?

 

[joe_padavano]

Code citation? Or is this another case of "I've always been told..." ?

You might want to brush up on how 240V circuits are wired...

 

[Rock knocker]

You might want to brush up on how 240V circuits are wired...

The poster you're chidding is one of the most respected electrician on this and several other boards. You might want to use a mirror.

 

[Smoker]

I wouldn't switch one leg of a 220 circuit either. Double pole switch.

 

[Norcal]

I wouldn't switch one leg of a 220 circuit either. Double pole switch.

220 only has 1 leg, 240 or 208 V has two legs. It is permitted to only switch one leg on 240V, a disconnect must disconnect all legs. 220 is a 50 hertz voltage.

 

[Rock knocker]

220 only has 1 leg..........220 is a 50 hertz voltage.

Not always

 

[justsam]

I would be more concerned about current limit and HP rating of switch since I assume it is switching compressor power and not just controlling a contactor.

 

[joe_padavano]

You might want to use a mirror.

I prefer to use a double pole switch (or other appropriate disconnect) on 240V circuits, actually.

If that poster is a respected electrician, then the post in question was very unclear as to it's intent.

 

[wyliesdiesels]

You might want to brush up on how 240V circuits are wired...

I take it youve never taken apart a baseboard heater line level thermostat that only switches one leg.

As has been said, u can switch off 240v equipment by switching one leg but if u need a means of disconnect such as for service, all legs need to be disconnected at the same time.

U scolded speedy pete and yet he is an electrician that does this every day. yes he knows how 240v circuits are wired as does Norcal and myself. What does that have to do with what has been said, which is code compliant? U clearly dont know what youre talking about

 

[justsam]

I take it youve never taken apart a baseboard heater line level thermostat that only switches one leg.
/QUOTE]

Or the thousands of of old mechanical Intermatic timers to control pool pumps. All SPST NO, and used around water no less!

Can you switch both sides, YES, because you are not breaking neutral, is it required, NO!

 

[wyliesdiesels]

240v equipment doesnt need a neutral so that doesnt make sense or apply.

 

[Rock knocker]

Somewhere, like maybe ET, a sparky is complaining about giving advice on a DIY forum. Like they say, no good deed goes unpunished.

 

[justsam]

240v equipment doesnt need a neutral so that doesnt make sense or apply.

Perhaps I was not clear in post. It is ok to switch both sides of a 240 circuit, however it is not required to do so. There is no neutral involved.

As opposed to a circuit using neutral, such as a 120 circuit, you may switch hot, but not neutral.

Bottom line is OP got his answer assuming switch is up to the task.

 

[Speedy Petey]

You might want to brush up on how 240V circuits are wired...

Really? Care to elaborate then?

The question was can a SP switch control a 240V receptacle.
Do you know what a means of disconnect is?
Are you aware that in this case the receptacle is the means of disconnect, NOT the switch?
In the case of the OP the switch is simply a control. Nothing more.

 

[Speedy Petey]

Perhaps I was not clear in post. It is ok to switch both sides of a 240 circuit, however it is not required to do so. There is no neutral involved.

As opposed to a circuit using neutral, such as a 120 circuit, you may switch hot, but not neutral.

This question really has nothing to do with whether a neutral is involved or not.

 

[sberry]

This is a good case where something may be able to be done legal but doesn't make it a good idea for everyone. If I was going to fug around with this in residential for a diy type would use a double pole and disconnect the power period.

 

[joe_padavano]

I take it youve never taken apart a baseboard heater line level thermostat that only switches one leg.

I have and obviously you are correct. The original question, however, was about switching an outlet, not a permanently-connected device. As noted above, there is often a difference between ************ and best practice.

 

[Smoker]

To me if I "turn something off" it means there's going to be no power to it. Period. I've had a shock from 220v because some clown didn't switch both hot wires and it lit up an ungrounded enclosure.. Not fun. Double pole switch, be safe, don't take ANY chances with this stuff.

 

[Rock knocker]

To me if I "turn something off" it means there's going to be no power to it. Period. I've had a shock from 220v and it isn't fun. Double pole switch, be safe, don't take ANY chances with this stuff.

That's what the disconnect at the compressor is for. The switch is only located in a convenient location.

 

[Norcal]

To me if I "turn something off" it means there's going to be no power to it. Period. I've had a shock from 220v because some clown didn't switch both hot wires and it lit up an ungrounded enclosure.. Not fun. Double pole switch, be safe, don't take ANY chances with this stuff.

If you got hit by 220V it was in a foreign country, in North America it is impossible to get hit by 240V or 208V unless you contact both legs.

 

[wyliesdiesels]

To me if I "turn something off" it means there's going to be no power to it. Period. I've had a shock from 220v because some clown didn't switch both hot wires and it lit up an ungrounded enclosure.. Not fun. Double pole switch, be safe, don't take ANY chances with this stuff.

The only way to get bit by 240v (220v hasnt been used here in decades) is by touching both hot legs.

If u touched an ungrounded enclosure that was energized, then u got zapped by 120v...

 

[Speedy Petey]

To me if I "turn something off" it means there's going to be no power to it. Period. I've had a shock from 220v because some clown didn't switch both hot wires and it lit up an ungrounded enclosure.. Not fun. Double pole switch, be safe, don't take ANY chances with this stuff.

If the switch is both the control and the means of disconnect, you are correct.

If there is a receptacle, and you relied on the switch thinking it would kill all power, AND didn't unplug the load, AND didn't check for no-power, you are an idiot and should not be working on electrical stuffs.

 

[Speedy Petey]

The only way to get bit by 240v (220v hasnt been used here in decades) is by touching both hot legs.

If u touched an ungrounded enclosure that was energized, then u got zapped by 120v...

I say this all the time when folks say they got "hit by 220". LOL!

 

[Dagny]

I use to correct people on this but quit because somehow they feel special having felt the higher voltage.

 

[nehog]

HD has DPST wall switches. They are not expensive.