wiring question

[SGKent]

Need to add an additional 240 volt circuit in the work Tuff Shed for a backup compressor.

View media item 16905
Right now the top 240V switch is about breast height. It controls a 240V 20A socket. Both the socket and switch are out of the reach of little goblins should there ever be any around.

Because of shelves in the way etc to add another similar circuit near it would end up with the new switch and socket below the existing socket which would be within the reach of little goblins. I was thinking the optimal solution would be to replace the switch box with a dual box of some kind and add a second switch within it, then move the existing 110V circuit elsewhere while reusing that box for the new 240V receptacle.

The issue in my mind is that even if code allows it, it probably isn't kosher to run two 240V circuits into a dual box because someone could flip a breaker, verify no voltage on one of the switches and get hurt from the voltage on the second circuit coming into the same box or in a fault, power could travel from one circuit to the other.

Does anyone have a simple solution for running multiple switches side by side where each box holding a switch could maintain a seperate conduit and isolated space? The solution has to be something a local hardware Lowes or HD would stock. Or if there is no such solution, would it be acceptable to use a standard dual gang box and handle-tie the two pairs of 240V breakers together so that if one is switched off the other does too?

 

[SGKent]

anyone have experience with this issue?

 

[pattenp]

I'm not sure of code issues with running two circuits to the same double box. I would probably just run the 120V and 240V circuits to two separate boxes to be on the safe side.

Edit: I think NEC 210.7 covers this. Where two or more branch circuits supply devices or equipment there needs to be a means to simultaneously disconnect all of the ungrounded conductors at the point where the branch circuits originate. Meaning you'd have to tie the breakers together.

 

[SGKent]

I'm not sure of code issues with running two circuits to the same double box. I would probably just run the 120V and 240V circuits to two separate boxes to be on the safe side.

The 120V is unswitched and can be moved. I need to add a 2nd 240V circuit. What I would end up with is a pair of 240V breakers and switches. After moving it I can reuse that 120V box for the new 240V socket. I am trying to protect the next person who goes in that box (and myself) 10 years from now if I forget each switch is on a seperate 240V breaker. What I am wondering is if there are multi-gang boxes where each gang is considered seperate. Or I can maybe redo framing to make room for another set of boxes.

 

[pattenp]

Look at edit to my post if you haven't noticed it..

 

[ishiboo]

The 120V is unswitched and can be moved. I need to add a 2nd 240V circuit. What I would end up with is a pair of 240V breakers and switches. After moving it I can reuse that 120V box for the new 240V socket. I am trying to protect the next person who goes in that box (and myself) 10 years from now if I forget each switch is on a seperate 240V breaker. What I am wondering is if there are multi-gang boxes where each gang is considered seperate. Or I can maybe redo framing to make room for another set of boxes.

Nothing against code having two separate circuits in there, just make sure they are 100% separate circuits... i.e., don't share an undersized ground or neutral between them.

You could also mount two steel boxes next to each other on the plywood. Or use one large box with a divider (made for separating low/high voltage circuits.)

I put a little note tag on the inside if there is something important... i.e., my upstairs is all new but due to rewiring the kitchen receptacles wire which was in the ceiling now goes to junction boxes in the walls, and I have a separate breaker box upstairs that feeds everything BUT those kitchen receptacles and a whole-house smoke/CO alarm system. So I have a small label on the panel which lets people know that those are "hot" even with all the breakers in the main panel "off".

 

[ishiboo]

I'm not sure of code issues with running two circuits to the same double box. I would probably just run the 120V and 240V circuits to two separate boxes to be on the safe side.

Edit: I think NEC 210.7 covers this. Where two or more branch circuits supply devices or equipment there needs to be a means to simultaneously disconnect all of the ungrounded conductors at the point where the branch circuits originate. Meaning you'd have to tie the breakers together.

That's only for two circuits running to the same device or equipment... i.e. a large machine cannot have two separate 240v breakers.

This does not mean you can not have two circuits switched separately in the same box, that's fine. As a courtesy to anyone who may work on it in the future, I label stuff like that, but I'm no professional electrician so nobody is likely to work on what I do for a long time

 

[pattenp]

Yeah.. after posting that code section I was thinking it was a stretch, because the box isn't a device or equipment.

That's only for two circuits running to the same device or equipment... i.e. a large machine cannot have two separate 240v breakers.

This does not mean you can not have two circuits switched separately in the same box, that's fine. As a courtesy to anyone who may work on it in the future, I label stuff like that, but I'm no professional electrician so nobody is likely to work on what I do for a long time

 

[SGKent]

You could also mount two steel boxes next to each other on the plywood. Or use one large box with a divider (made for separating low/high voltage circuits.)

All great ideas -

It sounds like what I am looking for then is maybe a dual or triple gang box with a divider(s) to keep circuits apart. Or use one large box with a divider (made for separating low/high voltage circuits. "Divider" is the key word I need to look for.

Or I can maybe fab a plywood panel in there with several boxes screwed to it.

 

[ishiboo]

All great ideas - Is a divider something commonly found at say HD or Lowes, or something more special order?

I know Lowes carries the Carlon SuperBlue boxes, which are just about the nicest plastic boxes you can buy, and the associated low voltage dividers. I think only the larger gang steel Raco's are set up for dividers.

I would just not have one though and go with a large box, it's going to be harder to try and keep each 240v apart in a single gang than have them both mixed in a double gang.

 

[SGKent]

I know Lowes carries the Carlon SuperBlue boxes, which are just about the nicest plastic boxes you can buy, and the associated low voltage dividers. I think only the larger gang steel Raco's are set up for dividers.

I would just not have one though and go with a large box, it's going to be harder to try and keep each 240v apart in a single gang than have them both mixed in a double gang.

Thank You. Last question. Each circuit will have its own ground sized for that individual circuit (probably either 12/2 w/gnd Romex or stripped from the Romex coat as I have plenty of that now and it is a high quality American made Romex). Can I just tie both grounds together inside the dual gang box etc so all the grounds are together at that spot or is someother solution better? The cable will be in metal conduit as well.

 

[cderalow]

why not just replace the 120V box with a combo switch/220V outlet in a 2 gang metal box? that way switch and outlet are right there, everything remains separate, and all you need is a new box & coverplate.

 

[SGKent]

why not just replace the 120V box with a combo switch/220V outlet in a 2 gang metal box? that way switch and outlet are right there, everything remains separate, and all you need is a new box & coverplate.

awesome idea. Totally eliminates the whole headache. Thank you. Brilliant. I can even reuse the existing conduit. All I need do is pull new wires if the ones in it now are undersized. Then add a 110V circuit on the other side of the door - easy.

 

[6768rogues]

Need to add an additional 240 volt circuit in the work Tuff Shed for a backup compressor.

View media item 16905
Right now the top 240V switch is about breast height.

I can't find the breast in the picture. I am sure it would help your post get attention.

 

[SGKent]

I can't find the breast in the picture. I am sure it would help your post get attention.

cute

 

[pentavolvo]

any reason for the switch on the 220 line

 

[SGKent]

it turns the main compressor on-off when I need to use it. I guess I could use that switch box for one socket and the other for the second then go back to using the manual lever on the compressors to turn them on. It is just so much easier to flip a switch than pull out the lawnmower etc to get far enough back in the shed to turn the back compressor on.

 

[Steevo]

I'm thinking electric fence or mine field to deter the goblins from ever reaching the shed.

 

[SGKent]

I'm thinking electric fence or mine field to deter the goblins from ever reaching the shed.

creative

 

[cderalow]

awesome idea. Totally eliminates the whole headache. Thank you. Brilliant. I can even reuse the existing conduit. All I need do is pull new wires if the ones in it now are undersized. Then add a 110V circuit on the other side of the door - easy.

what is it they say, sometimes the simplest solution is to just not think too hard about it?