sanity check please - another electrical question

[Jon Prouty]

Hi All,

Just picked up a 18,000 BTU AC unit for my garage shop to replace an old piece of junk unit. This is a window unit so I did not even think of the power requirements until I got to work and looked up the reviews on-line and saw that it is a 240v unit. Hmmm... I have no 220 (240) outlets in the garage but I do have a dryer outlet on the other side of a common wall to the garage. I can't expense an electrician to run 220 out to my garage to run this ac so I plan to do the following:
Get a good 12 guage extension cord form the BORG and the approriate plug to connect to my dryer receptacle and the appropraite receptacle to mate to the AC unit. Badda boom, badda bing, cut the ends and wire up the new ends. White and black to the side lugs and green to the D shaped ground for the dryer side and match the colors on the AC unit. Easy peasy right?

I will drill a hole through the wall to have my new cord run through (before putting on on end).

I will have to swap plugs with the wife but such is life - dryer vs garage AC.

Any problems with my logic here? Only worry is not drilling through a wire in the wall.

Sanity check please?

Thanks!
Jon

[Dan Hintz]

Electrically, there's nothing wrong with this setup...

Code wise, you are breaking several rules in one shot, not to mention opening yourself up to a lawsuit and a good way to be denied homeowner's insurance claims should something go wrong.

Extension cords are not allowed to be run through/in a wall. Extension cords are not allowed to have their ends lopped off and used as a permanent power source. I won't get into the other code violations on this one as those alone will end any claims...

[Jon Prouty]

Electrically, there's nothing wrong with this setup...

Code wise, you are breaking several rules in one shot, not to mention opening yourself up to a lawsuit and a good way to be denied homeowner's insurance claims should something go wrong.

Extension cords are not allowed to be run through/in a wall. Extension cords are not allowed to have their ends lopped off and used as a permanent power source. I won't get into the other code violations on this one as those alone will end any claims...

Permanent power source... I would say this is a temporary summer situation. Not a permanent installation?

Can I daisy chain off the existing dryer outlet and put a box in the wall next to the existing but facing into the garage? Obviously only running one unit at a time (dryer or AC unit). This would get me by the cord through the wall aspect.

Thanks!
Jon

[Dan Hintz]

Permanent power source... I would say this is a temporary summer situation. Not a permanent installation?

Can I daisy chain off the existing dryer outlet and put a box in the wall next to the existing but facing into the garage? Obviously only running one unit at a time (dryer or AC unit). This would get me by the cord through the wall aspect.

Thanks!
Jon

Lopping off the end of the cord and wiring it to the box makes it "permanent", regardless of how long you intend to leave it that way.

But yes, adding another box with proper Romex wiring between the two is the appropriate way. Granted, it wouldn't pass code muster if the A/C is considered a permanent fixture due to the lack of proper gauge wire/breaker for both at the same time... you'd have to tell the guy you want to move the dryer from one place to another from time to time, hence the dual plugs. Still, if you have no plans to sell it that way or get it inspected, you'll be fine. Just make sure you don't run both at the same time as you'll wear out the breaker tripping it so often

[Jon Prouty]

I guess in my original plan I wouldn't be wiring it to a box, rather I would be making an extension cord. That would have a plug on the end that would mate to the exisitng receptacle. Seeing as this is a code problem to have an extension cord through a wall, I suppose an extension cord made from Romex would be just as bad. Most of the cord would be out of the wall and the flexure at the dryer end would be numerous times.

I think wiring up another box is the way to go.... I would only need a couple feet of Romex, a box and an outlet.

Time to contemplate this a bit more.... I really appreciate the feedback (sanity check).

Jon

[John McClanahan]

Your dryer is probably on a 30 amp breaker. To be safe, the wire should be 10 gauge.

John

[Roger Frazee]

Jon

You should reconsider. What plug is on the factory power cord for the a/c? Most likely at 240 volts it's a 6-15p with an LCDI. The power cord will not be protected by the 30 amp breaker being utilized by the dryer branch circuit. The simple fact is your plugging a 15 amp a/c cord into a 30 amp circuit. Not a good idea.

Is there anyway you can rededicate one of your 120 volt 15 or 20 amp circuits to a 240 volt circuit?

[Bernie May]

why not return the 220 unit and get a 110 version even if it is smaller. Not sure the size of your workshop or the degree of insulation. but we don't usually have to cool our shops to the level in a house and it is usually just one big room and does not involve all of the ducting. you can turn on your overhead air filter to help move the cool air around.
-bernie

[Dan Hintz]

The power cord will not be protected by the 30 amp breaker being utilized by the dryer branch circuit. The simple fact is your plugging a 15 amp a/c cord into a 30 amp circuit. Not a good idea.

It's done every day... I plug 14 Gauge wired appliances into 20A breakers (using 12 Gauge Romex) all of the time, there's no problem with it. The breaker is not there to protect the wiring of the appliance, it's there to protect the wiring within your walls. If the appliance has the potential to pull more current than it is hardwired for (i.e., the cord sticking out of the back), it's up to the appliance manufacturer to include some form of protection (breaker, fuse, etc.) within the appliance.

What would be wrong is changing the plug to fit into a differently-rated outlet.

[Jon Prouty]

why not return the 220 unit and get a 110 version even if it is smaller. Not sure the size of your workshop or the degree of insulation. but we don't usually have to cool our shops to the level in a house and it is usually just one big room and does not involve all of the ducting. you can turn on your overhead air filter to help move the cool air around.
-bernie

I have a small one (5k BTU / 110V) in there now and it does not do a great job. It is 115 here in AZ and my four car garage needs a bigger unit to cool to an acceptable temp. While fully insulated, the garage is hotter than I can deal with when working out there. Monsoons are here now so humidity is up where evap cooler is no good.

JP

[Jon Prouty]

Jon

You should reconsider. What plug is on the factory power cord for the a/c? Most likely at 240 volts it's a 6-15p with an LCDI. The power cord will not be protected by the 30 amp breaker being utilized by the dryer branch circuit. The simple fact is your plugging a 15 amp a/c cord into a 30 amp circuit. Not a good idea.

Is there anyway you can rededicate one of your 120 volt 15 or 20 amp circuits to a 240 volt circuit?

I don't understand... a 30 amp circuit should be more than necessary for a 15 amp AC unit. I would consider a 15amp circuit for a 15 amp requirement borderline. Wouldn't that trip the breaker everytime?

Your second point intrigues me though... I do have this outlet in my laundry room. This appears to be a NEMA 5-20R 20 amp dedicated outlet. Can I reconfigure to 220? What would be involved?

[Brad Sperr]

I don't understand... a 30 amp circuit should be more than necessary for a 15 amp AC unit. I would consider a 15amp circuit for a 15 amp requirement borderline. Wouldn't that trip the breaker everytime?

Your second point intrigues me though... I do have this outlet in my laundry room. This appears to be a NEMA 5-20R 20 amp dedicated outlet. Can I reconfigure to 220? What would be involved?

If that outlet is on a dedicated, home-run circuit back to your panel, you could use the grounded (white) conductor as the second line conductor for a new 220 circuit. You might have to reposition some breakers to make room for a new double pole breaker to ensure that the two lines are on opposite legs of the service. Be sure to mark the grounded conductor with a Sharpie to indicate the change. Technically, you're still required to have a dedicated 20amp circuit serve your laundry room, though.

[Dan Hintz]

If that outlet is on a dedicated, home-run circuit back to your panel, you could use the grounded (white) conductor as the second line conductor for a new 220 circuit. You might have to reposition some breakers to make room for a new double pole breaker to ensure that the two lines are on opposite legs of the service. Be sure to mark the grounded conductor with a Sharpie to indicate the change. Technically, you're still required to have a dedicated 20amp circuit serve your laundry room, though.

It's already a 220V circuit, so both lines are being used.

[Brad Sperr]

I'm assuming that's a picture of another receptacle in the laundry room. The NEMA 5-20R is not rated for 240V, so that should be a 120V circuit. You would need a new receptacle if you were to convert that circuit to 240V.

[Jon Prouty]

I'm assuming that's a picture of another receptacle in the laundry room. The NEMA 5-20R is not rated for 240V, so that should be a 120V circuit. You would need a new receptacle if you were to convert that circuit to 240V.

correct - this is another unused receptacle in the laundry room. I think having this converted would be a good solution.