1. Electrical question - 220v

If I have a device that is 220v I need a switch to turn it on and off.

The 220v circuit is 2 hot wires - really nothing else is needed. A ground is a nice to have, and I will ground.

Do I need to break both hot leads? I think I should break both. In a 110v I need to only break only one lead.

Sooo, on a 220v circuit, what does a switch look like, assuming relatively low amperage (2a) What does a switch look like for 15a
Is this a double pole single throw switch (DPST)?

Can you post links to Amazon possible switches for those 220v circuits?

2. Leo, you have it right DPST is what you want, Carling makes a very good switch , a little more costly, but a good product.
https://www.amazon.com/s/ref=nb_sb_s...ST%2Caps%2C144

3. Correct, break both leads using a DPST switch. Looks like Charles has you hooked up on the link.

4. If you want to live on the edge, you could get one of these "safety" switches

5. You can also get wall switches
https://www.amazon.com/Leviton-CS220.../dp/B000U39UC6
https://www.amazon.com/Leviton-MS302.../dp/B002MPQ51O

Push button switches
https://www.amazon.com/Woodstock-D41.../dp/B005W17GZE

https://www.amazon.com/Woodstock-D41.../dp/B005W17FRS

The reason you want double pole is that in a 110v circuit only one "leg" is hot - so if you interrupt that leg you can't complete the circuit with either the neutral or the grounding wires. You also want to interrupt the hot leg in that case, if you find a switch that is switching on the neutral its a hazard condition because the circuit is still energized and needs to be fixed asap. With 220 both wires are hot, so you can complete the circuit from either of them to either a grounding wire or to the earth itself (because that shares a common ground). This is also why its a BAD IDEA to do things like wire together two 110v switches or breakers, because if one trips and the other doesn't the load can all go through the untripped side overload the rest of the circuitry (i.e. the wire) quicker than the breaker can trip causing a flash and thus a fire.

6. Originally Posted by Brent Dowell
If you want to live on the edge, you could get one of these "safety" switches

Aww, that's fine looking. Be sure to throw those with verve so they aren't left doing the arky sparky dance. I've welded a couple of those shut by being hesitant

7. FANTASTIC - Great suggestions.

I know what to do now

8. Originally Posted by Brent Dowell
If you want to live on the edge, you could get one of these "safety" switches

Ahhhh YES - Double Pole Single Throw.

This is what I had in mind.

9. One thing to consider (based on the type of equipment you're using)... is a magnetic interlock switch. Basically they will shut off if the power is disconnected and NOT turn back on if the power comes back. They are substantially more expensive though. I don't know your use case here, but it might be a consideration depending on the possible projected failure modes....

For example:
http://www.grizzly.com/products/Magn...campaign=zPage
http://woodworker.com/1hp-5-8amp-1ph...su-923-950.asp

Grizzly has a nice selection of switches overall..
http://www.grizzly.com/search?q=(categoryid:275010)

If you're looking for a more central maintenance disconnect something like this
http://www.homedepot.com/p/GE-60-Amp...0RCP/100674085
actually works pretty well.. It would be used if you have an piece of equipment that you want to completely cut _all_ power to for infrequent periodic maintenance (commonly things like hard wired air compressors or dust collectors). The nice thing about this sort of disconnect is that you can LOCK the disconnect so no one can re-energize it without removing your lock (common practice in industrial settings - search "lock out tag out" for more). I wouldn't use it for something you needed to disconnect more than say monthly as the interface isn't really rated for a high duty cycle.

10. I've used this switch on several tools for about three years. They work great!

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