sanity check please - another electrical question

[Roger Frazee]

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.

I concur that is not a 240 volt circuit but a 120 volt circuit. As you said if it is a dedicated home run it can easily be converted to 240 volts as long as there is room for a double pole beaker to be added to the panel.

You need to absolutely verify no other outlets on that circuit. Since it is a single outlet there is a great chance for that to be true. It is then a simple matter to convert it to a 240 volt circuit that will match the manufacturers required branch circuit requirements for the a/c.

Jon

The NEC specifically forbids any listed 15 or 20 amp rated cord and plug appliance like your window a/c to be operated on a 30 amp circuit. Below is a manual telling you as much. You are requied by the electrical codes to fololow the manufacturers instructions. Lots of things 'work' but not necessarily safely.

http://manuals.frigidaire.com/prodin...219a0951en.pdf

What Dan said earlier is true you can operate 15 amp appliances on a 20 amp circuit but his reasoning is incorrect. But that is where it ends.
If this is a new unit the manufacturer will tell you the same in the installation instructions. You risk fire at the A/c if the right conditions would suddenly exist.

Again you cannot connect to a 30 amp branch circuit with appliances that have 15 or 20 amp cords and plugs. This is a direct violation of the NEC and local codes.

The explanation will take some time and code references but it is not a matter of whether or not the circuit has more than enough power to operate the window a/c. I'll provide that if you like.

Simply put if the manufacturer wanted to allow you to put the window a/c on a 30 amp circuit they would have put a 30 amp plug on it..... It's not about voltage but the available amperage. The manufacturer is required to protect the compressor with an overload device and he protects the wiring of the unit (power cord) by sticking that 20 amp or 15 amp plug on the unit to force you to use a 15 or 20 amp branch circuit.

[Jon Prouty]

I concur that is not a 240 volt circuit but a 120 volt circuit. As you said if it is a dedicated home run it can easily be converted to 240 volts as long as there is room for a double pole beaker to be added to the panel.

You need to absolutely verify no other outlets on that circuit. Since it is a single outlet there is a great chance for that to be true. It is then a simple matter to convert it to a 240 volt circuit that will match the manufacturers required branch circuit requirements for the a/c.

There is room to add a double pole breaker in the box. Stupid question - how do I verify without a doubt that there are no other outlets on this circuit?

Is this something that needs to be done by an electrican or is this something that a (reasonable) homeowner can do?

I have done more reading and agree that I cannot plug this AC unit into a 30amp dryer circuit.

Thanks all again for the great support.

Jon

[Roger Frazee]

Hi Jon

Yep you can do this yourself. There is a excellent chance this circuit is dedicated by evidence the outlet is a single (not duplex) receptacle.

Basically get a voltage tester or lamp and turn off the breaker that supplies that receptacle. Check every outlet that could be reasonably supplied by this circuit. If any other outlets have lost power then it is not dedicated. Even if more outlets you may still be able to do this but we need the details.

I can post a diagram if this becomes a possibility. You can definitely do this yourself.

[Trevor Howard]

You can buy a tracer, basically a sender unit plugs into the outlet and then you go down your panel with a receiver unit that beeps when it finds the right breaker. Or a cheaper way is to switch the breaker off, then go around outlets within range of the Laundry room receptacle, and test for power.

If you go this route, will you still wire up a receptacle on the garage side?

[Jon Prouty]

You can buy a tracer, basically a sender unit plugs into the outlet and then you go down your panel with a receiver unit that beeps when it finds the right breaker. Or a cheaper way is to switch the breaker off, then go around outlets within range of the Laundry room receptacle, and test for power.

If you go this route, will you still wire up a receptacle on the garage side?

Going to use the lamp trick. Should be easy enough. (I am king of cheap).

I will move the outlet to the garage side of the wall.

I'm headed to the borg to get some supplies. I'm sure I'll have more questions later guys. Thank you again to everyone for the help.

Jon

[Dan Hintz]

Roger,

You're absolutely correct... I was under the (poor) assumption the A/C unit was properly plugged for a 30A circuit, hence my assertion that he was perfectly fine with plugging the unit into that circuit. My bad...



Jon,

An earlier post (around #12ish) made it appear that you were going to rewire the pictured socket to the 30A dryer circuit. This is not correct, as Roger pointed out, since the pictured socket is not rated for 240V. I assumed (again, poorly) that you were installing a new socket (one properly rated) and connecteing that to the 30A circuit... a new socket properly rated for a 30A circuit would not allow you to plug in a 120V appliance (at least not without a lot of heavy plier work).

[Roger Frazee]

Roger,

You're absolutely correct... I was under the (poor) assumption the A/C unit was properly plugged for a 30A circuit, hence my assertion that he was perfectly fine with plugging the unit into that circuit. My bad...



Jon,

An earlier post (around #12ish) made it appear that you were going to rewire the pictured socket to the 30A dryer circuit. This is not correct, as Roger pointed out, since the pictured socket is not rated for 240V. I assumed (again, poorly) that you were installing a new socket (one properly rated) and connecteing that to the 30A circuit... a new socket properly rated for a 30A circuit would not allow you to plug in a 120V appliance (at least not without a lot of heavy plier work).

Dan

Not a problem. Misunderstanding what the OP was doing is something I do all the time

Lets all put our heads together and help Jon get his new circuit run for his window a/c .... gotta be freakin hot in Arizona without A/c .... It's dang near unbearable here in Kansas.

[Roger Frazee]

Going to use the lamp trick. Should be easy enough. (I am king of cheap).

I will move the outlet to the garage side of the wall.

I'm headed to the borg to get some supplies. I'm sure I'll have more questions later guys. Thank you again to everyone for the help.

Jon

Hi Jon

Thought I would throw up this diagram at the end of my reply for you to reference while you get ready to run your new circuit.

Your going to be inside your breaker box. If you have not been in one before then get your head on right and stay focused. If your panel has a main breaker in it...turn it off. It generally is considered added safety if you turn off all your smaller branch breakers first to avoid disconnecting a high amperage combination of loads. Remember though the main breaker lugs will always be hot. With luck you may have a remote main breaker in which case you can de-energize everything in the panel.

Your going to look at the single pole breaker that is protecting the circuit to the laundry. Determine what you need to do to open up a space either above or below that breaker or if the wire will reach just install a double pole breaker in two open slots.

Word of caution a tandem "twin breaker " is not a double pole breaker and will not facilitate 240 volts ... so be sure you have a double pole breaker. Any problem with that understanding be sure to ask us here.

Once once you determine where you want the new breaker then remove the black wire from the existing single pole breaker. I prefer in most cases with small conductors to install the wires into the new breaker first .. then place it into the panel. How you do this varies so just study things a bit and you see how that is done. Be sure your wires are the correct length to connect to the breaker. If the wire or wires are too short then make pigtails with wirenuts.

So connect the white wire and the black wire to the circuit breaker. To be code compliant take a black magic marker and color a bit of the white wire black where it connects to the breaker. this identifies it as a white wire being used as hot. Doesn't matter which wire goes to which lug. Install the breaker ... your done.

Put the cover back on... then main breaker back on then all the branch breakers back on. Be sure the rest of the a/c circuit is completed before energizing.

Rest of the circuit looks like the diagram below. You will be extending the branch circuit from the existing receptacle in the laundry room. Just connect white to white, black to black and connect the equipment grounding. Do not use extension cord. Remove the 120 volt receptacle and put a blank cover over the box ...you must have access to the junction.

Hope this all makes since

[Jon Prouty]

Hi Guys... just want to thank you all again for the assistance. What a group of great folks here.

I thought I would put up a sketch to clarify a bit more the issue so that we're all on the same page. Also took a picture of the AC box electrical requirements.

I stopped by the borg and got everything I need except the breaker - guy recommended that I bring in the 110 breaker so that he can get me the right 220 for my box.

I think this will work out okay... you ain't kidding about needing the AC, it is HOT here in AZ.

Thanks!
Jon

[Jon Prouty]

Roger - thank you so much!!! All makes perfect sense. The guy at the borg said not to worry about flipping the main breaker off - that made me a bit nervous. I think I'd rather have that off.

Only other thing is that I will use a 6-15R rather than a 6-20R.

I should be golden now - I hope.

JP

[Dan Hintz]

Jon,

The very first thing I did when I moved in with my SO was have them replace the main panel (circa '72) with one containing a main breaker. Granted, I haven't used it yet, and I've already installed/replaced quite a few circuits in the house, but it's nice to know it's there.

[Roger Frazee]

Roger - thank you so much!!! All makes perfect sense. The guy at the borg said not to worry about flipping the main breaker off - that made me a bit nervous. I think I'd rather have that off.

Only other thing is that I will use a 6-15R rather than a 6-20R.

I should be golden now - I hope.

JP

Your welcome Jon

Turn off the main ... this removes several points where you may short a screwdriver or bare end of a wire. Any exposed buss will also be de-energized. You may have to reset some clocks etc ... but better than
.

6-15R is fine and what is needed for the a/c plug

Since the wire is 12 awg or should be since the existing 120 volt 5-20R receptacle is a single one and dedicated home run just continue the extension to the new location with 12 awg. The manufacturer is showing a connection to a 6-15 then you can if you want just install a 15 amp double pole breaker on the 12 awg.

[Jon Prouty]

okay, last question I think. I was thinking of running an extension cord from the AC to the new plug location. However, since it is a garage, I could run 12-2 Romex in a conduit along the wall and put a handybox in the right location for the AC to just plug into. Cheaper than making an extension cord and probably a better install anyway. I'll make the first connection from the wall to the splice in a handybox so that should be to code.

Good idea?

Looking forward to a cool garage this weekend.

Jon

[Roger Frazee]

okay, last question I think. I was thinking of running an extension cord from the AC to the new plug location. However, since it is a garage, I could run 12-2 Romex in a conduit along the wall and put a handybox in the right location for the AC to just plug into. Cheaper than making an extension cord and probably a better install anyway. I'll make the first connection from the wall to the splice in a handybox so that should be to code.

Good idea?

Looking forward to a cool garage this weekend.

Jon

Yep good idea, the manufacturer warns against extension cords but it looks like your distance is not very far.
Conduit is better and code compliant ... I like EMT but that choice is yours. You be using metal boxes so ground the boxes.

Generally it is better to run individual conductors of thhn wire ( solid or stranded) in conduit.

1/2" conduit is too small for 12 awg romex and you would violate conduit fill requirements.

I wouldn't ding you though if you use 3/4 emt or pvc with a run of 12 awg romex.

If you run 12 awg thhn you can use 1/2" conduit.

[Dan Hintz]

Thumbs up from me... (as if it mattered )