Wiring Nema 6-50 outlet with switch?

[PT Doc]

I'd like to have a switch as part of the wiring from the compressor to the 6-50 receptacle. The circuit will be 6/2 50A. I have seen metal cover plates that have an outlet opening and a skinny switch opening. Can this be done?

Also, what type of box should I use for the 6-50 outlet? Metal or plastic? Flush with drywall or surface mounted? Thanks

 

[dittle fart around]

Install a disconnect box like this one from Platt they are a commercial and industrial electrical supplier.
View media item 11639That's the switch. surface mount it and attach outlet directly to the bottom of the switch. If your walls are open run the wire in the studs. Make holes in the studs for each conductor. The conduit required for surface mount should be large enough for the two 6's and ground probably 2" or more. Also consider running a trough. Easier than conduit mounts to wall with an cover the full length.

 

[PT Doc]

No other smaller/cheaper option? Thanks

 

[TWX]

To my knowledge, there aren't any consumer-type switches for anything above 20A. All industrial/commercial.

I used a box with all discrete parts for the outside-mounted 6-50R at the old house, but at the new house I just used a surface-mount 6-50R that didn't need anything other than the pipe fitting. That one is inside and out of the weather, and it was a lot cheaper to not have to buy the box, the cover, and the receptacle.

I frequent a used building supplies place around here called Stardust Building Supplies. They sometimes have used panels, switches, etc. You might look to see if a similar type of place is local to you, as this kind of stuff generally doesn't go bad.

 

[dittle fart around]

Use the breaker as your switch. Surface mounted conduit to box.

 

[dittle fart around]

No other smaller/cheaper option? Thanks

There is no such thing as cheap commercial wiring. The requirements are there to protect equipment first the employee second and are set up to protect the lowest common denominator. Nothing personal.

 

[Charles (in GA)]

Get an A/C disconnect box from HD or Lowes, about $10-$14. They make them for 30 amp and for 60 amp. Some are pull out type, you really don't want that if you are going to be using it all the time. They make a swtich type, look for one of those.

Charles

 

[PT Doc]

Neat option, but not cheap:

http://www.amazon.com/gp/aw/d/B003AU8QVC/ref=aw_d_detail?pd=1&qid=1315769772&sr=8-11

 

[TWX]

That's pretty cool! I may have to get myself one of those for my air compressor. I was tempted to use a 20A switch (compressor would run at 120V 20A but would trip the breaker when it got up to higher pressure, so I figure 240V is probably running well under 20A) but I've never gotten around to it. That switch looks like it would actually do it right without requiring me to keep using the circuit breaker as the switch...

 

[PT Doc]

Here is another option, but even costlier:

http://www.amazon.com/gp/aw/d/B003B8Z9YU/ref=aw_d_iv_hi?is=l

 

[eriksalo]

I second the motion to use an A/C switch or SPA switch. They are small, cheap and can be had with 50A breakers. You can also get a GFCI version for a few more dollars.

Home Depot or Lowe's should have a selection.

 

[mrb]

They sometimes have used panels, switches, etc. You might look to see if a similar type of place is local to you, as this kind of stuff generally doesn't go bad.

actually it does go bad, and its illegal to install used material without written approval from the AHJ (the building official, not inspector looking the other way or missing it)

EDIT, i might be wrong here -the new material requirement might be local. That said, using used breakers is not a good idea.

 

[StaggeringGoat]

Can't beat this price...
http://www.homedepot.com/h_d1/N-5yc...P_PARENT_ID&storeId=10051&Ntpr=1&ddkey=Search

 

[Delta74]

lots of good options and idea's here, another option ( 100 bucks ) you could use a contactor with a 120 v trigger, could use a standard light switch to power your compressor or add a light like others have done, so when you walk out of the garage you just hit the switch and its dead, could use a 3 pole and use lines 1 and 3, just never break a neutral if you deceide on this route.

http://www.galesburgelectric.com/GE-CR353EE3BA1-50A-Definite-Purpose-Contactor-Standard-3-Pole.html

lots to check out thats just a quick example, can get 2,3,4 poles, and the coils anywhere from 24 volt and up, so lots of options. and put it in a box say 10 by 10 by 4 so you have lots of room to wire it, its covered and everyone aka inspector is happy.

 

[eriksalo]

lots of good options and idea's here, another option ( 100 bucks ) you could use a contactor with a 120 v trigger, could use a standard light switch to power your compressor or add a light like others have done, so when you walk out of the garage you just hit the switch and its dead.

I do this exactly with my 7.5 hp Speedaire compressor except I use a low voltage contactor. The compressor is 90 feet from my workspace (so I can't don't hear it) and I can just switch it on and off with a simple low voltage switch.

 

[Aceman]

actually it does go bad, and its illegal to install used material without written approval from the AHJ (the building official, not inspector looking the other way or missing it)

We install used equipment all the time without any issues. I can't even imagine asking the inspector for written consent everytime a customer wanted to save a little money and have us install something used out of our inventory. Most of the time it's meterbases, gutters, pump panels, starters, etc that we'll install used if we need too.

 

[mrb]

We install used equipment all the time without any issues. I can't even imagine asking the inspector for written consent everytime a customer wanted to save a little money and have us install something used out of our inventory. Most of the time it's meterbases, gutters, pump panels, starters, etc that we'll install used if we need too.

hmmm, im going to have to do some digging. It might be a local thing for me, i thought it was in the NEC that material had to be new.

hopefully you dont install used molded case breakers....

 

[PT Doc]

lots of good options and idea's here, another option ( 100 bucks ) you could use a contactor with a 120 v trigger, could use a standard light switch to power your compressor or add a light like others have done, so when you walk out of the garage you just hit the switch and its dead, could use a 3 pole and use lines 1 and 3, just never break a neutral if you deceide on this route.

http://www.galesburgelectric.com/GE-CR353EE3BA1-50A-Definite-Purpose-Contactor-Standard-3-Pole.html

lots to check out thats just a quick example, can get 2,3,4 poles, and the coils anywhere from 24 volt and up, so lots of options. and put it in a box say 10 by 10 by 4 so you have lots of room to wire it, its covered and everyone aka inspector is happy.

This sounds like it would work out the best for me. Can you elaborate a bit on what I would need. I'm going to run 6/3 write but will not be using 1 them for now. I want to run from the sub panel (50a)to some switch and then from there to the nema 6 50 receptacle. Could I have the switch be a larger decora rocker type switch? How would this be wired? Would the contactor ned to be just a 2 pole in this case? Could this contactor be put into 2 slots of a 3 gang box and the rocket switch take the 3rd spot?
Thanks for the info.

 

[eriksalo]

Hi PTDoc;

The contactor (relay) can be thought of as two separate circuits. The first is the load or "high current" circuit. The second is the control or "low current" circuit.

For the load circuit, you wire the contactor in just like it's a switch. The two hot wires go in one end, are switched on and off by the contactor and come out the other side. Just like Delta74 said, don't put the neutral (or ground for that matter) into the switch, it should never be disconnected. The three gang contactors are pretty common. If you get one, it will work just fine but you only need to use two gangs, just don't put any wires into the middle switch circuit, that won't hurt the contactor. Make sure to use a contactor rater in amperage as large or larger than the breaker controlling the circuit. Larger is just fine, smaller isn't. Also, the contactor needs to be rated to 240 volts AC.

For the control circuit, first make sure that you contactor "coil" is 120V AC. This means that the contactor is switched on an off by a 120V AC signal. There are many types of contactor coils. Some are 24V DC, some are 12V DC, some are 120V AC, some are 240V AC, some have an interchangeable coil. You get the idea, you are looking for 120V AC and that should be easy to find.

Now, you can think of the 120V AC contactor "coil" just like a light bulb and you can wire it that way and use any regular household 120V switch. When the coil has 120V applied (e.g. the switch is on) then the contactor will make the connection of the large wires and your compressor will operate. When there is no voltage applied (e.g. the switch is off) the contactor will not connect the large wires and the compresor won't work. There are contactors that are "on" until you apply voltage to the coil but they aren't as common. You will want a contactor that is "open" when the voltage is off.

Regarding the question of putting the contactor in a "three gang" box, I'm assuming you are thinking of a box with three "breaker" slots. If I'm correct in my assumption, than you can not do this. Those boxes are fom circuit breakers. Many contactors come in a box or you can get an empty electrical box and put it in yourself. If your switch is close to your compressor, why not just get a spa disconnect as some of us have suggested? The reason to do the contactor is so that you can put the switch far away from the compressor and have a "remote" switch for turning it on and off.

I hope this helps.

 

[PT Doc]

Hi PTDoc;

The contactor (relay) can be thought of as two separate circuits. The first is the load or "high current" circuit. The second is the control or "low current" circuit.

For the load circuit, you wire the contactor in just like it's a switch. The two hot wires go in one end, are switched on and off by the contactor and come out the other side. Just like Delta74 said, don't put the neutral (or ground for that matter) into the switch, it should never be disconnected. The three gang contactors are pretty common. If you get one, it will work just fine but you only need to use two gangs, just don't put any wires into the middle switch circuit, that won't hurt the contactor. Make sure to use a contactor rater in amperage as large or larger than the breaker controlling the circuit. Larger is just fine, smaller isn't. Also, the contactor needs to be rated to 240 volts AC.

For the control circuit, first make sure that you contactor "coil" is 120V AC. This means that the contactor is switched on an off by a 120V AC signal. There are many types of contactor coils. Some are 24V DC, some are 12V DC, some are 120V AC, some are 240V AC, some have an interchangeable coil. You get the idea, you are looking for 120V AC and that should be easy to find.

Now, you can think of the 120V AC contactor "coil" just like a light bulb and you can wire it that way and use any regular household 120V switch. When the coil has 120V applied (e.g. the switch is on) then the contactor will make the connection of the large wires and your compressor will operate. When there is no voltage applied (e.g. the switch is off) the contactor will not connect the large wires and the compresor won't work. There are contactors that are "on" until you apply voltage to the coil but they aren't as common. You will want a contactor that is "open" when the voltage is off.

Regarding the question of putting the contactor in a "three gang" box, I'm assuming you are thinking of a box with three "breaker" slots. If I'm correct in my assumption, than you can not do this. Those boxes are fom circuit breakers. Many contactors come in a box or you can get an empty electrical box and put it in yourself. If your switch is close to your compressor, why not just get a spa disconnect as some of us have suggested? The reason to do the contactor is so that you can put the switch far away from the compressor and have a "remote" switch for turning it on and off.

I hope this helps.

Thanks for the info and clarification. I think I'll be using the contactor for my setup. The dos disconnect is too big and these breakers bring used as on / of switches make me robert how long they will last. Thanks again.

 

[mrb]

youre going to need an enclosure for the contactor, which will be as big as or bigger than the disconnect box you dont want. And its going to cost you ~$100. Just use the breaker (if the breaker says SWD on it, its rated for switch duty) when it wears out replace it. If it dies every 2 years you have 20 years of breakers for the cost of the contactor (which may not last 20 years). Or use a small A/C disco.

Look for a Square D QO200TRCP its around $12 and is a very small 60 amp disconnect. Has a switch in it that looks like a QO breaker. Mount that and a 4S box next to it with your receptacle and you have a clean cheap setup.

 

[mrb]

here are the dimensions of the SQD. its small.
Depth: 3.88 Inches
Height: 6.50 Inches
Width: 4.63 Inches