I’d like to be able to use a 240v window a/c unit I have. The plug is 20A so I need a 20A circuit. My service panel has two unused 30A breakers, on different hot legs, but they are not physically next to each other, and can’t really be moved, in order to replace them with a 2-pole 20A breaker. I presume it wouldn’t be kosher to replace each 30A breaker with a 20A, as they couldn’t be turned on/off together?
My thinking was to run hots (and ground) from those two breakers to a new breaker box just for the a/c. I found a 60A “Enclosed Molded Case Switch Not Fusible, Typical use a/c disconnect” at the big box store. The switch clearly says no overcurrent protection. However a 2-pole 20A breaker looks identical to the original switch and fits perfectly.
Any reason this wouldn’t work and be safe/legal?
Thanks.
Thon
Replies
"I presume it wouldn't be kosher to replace each 30A breaker with a 20A, as they couldn't be turned on/off together?"
No, basically any load with two not legs on it has to have a 2 pole breaker (or 2 single pole with tied handles).
"new breaker box just for the a/c. I found a 60A "Enclosed Molded Case Switch Not Fusible, Typical use a/c disconnect" at the big box store. The switch clearly says no overcurrent protection. However a 2-pole 20A breaker looks identical to the original switch and fits perfectly."
Sounds like a Sq D QO box. I have done the same thing on line central air when I found that they ran it off of a 60 amp breaker, but the AC needs to be protected at 20 amps.
However, in your case you still have the same problem with using the disconnect/breaker. It is being feed by two separate single pole breakers.
Some one could think that it was dead after turning off just one of them.
"but they are not physically next to each other, and can't really be moved, "
Why not?
<"but they are not physically next to each other, and can't really be moved, "Why not?>This is an old Federal Noah (?) service entrance box (outside) with a 70 A breaker feeding an inside service panel (which is full, though house is TINY). The 70A is in the center of the box, with a single pole 30A, on either side of it--both unused. IIRC, the way the box is set up, moving the 70A to one side or the other will not allow it to catch both hots.I couldn't find the particular code that dealt with 2 pole breakers vs tied handles. Can you point me to it?Thanks.Thon
In the 99 NEC it is 240-20 (b)A circuit breaker shall open all ungrounded conductors.There are 3 exceptions. 1) multi-wire circuits where no load see both hots, 2) single pole breeakers with approved tie-handles. the 3rd one is ome 3 phase systems.
Can you just add a breaker or fused disconnect to the panel?
I 'think' that's what I'm attempting to do but doesn't appear it will meet code.Thanks.Thon
There are disconnects that use breakers almost everywhere here. Maybe local codes there are different.
Maybe we're miscommunicating but as I understand it, the problem is not the disconnect, but the service panel--where I need to have a double pole breaker. I understand Bill, and the code, to be saying that even though I might have a double pole breaker at the disconnect, that doesn't obviate the need for the same at the service entrance.Thon
Under some conditions it's legal to run an unfused tap from the output of the fused disconnect (or directly off the bus bars of the panel) to a separate breaker box.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
<Under some conditions it's legal to run an unfused tap from the output of the fused disconnect (or directly off the bus bars of the panel) to a separate breaker box.>What conditions?<I was referring to running a new disconnect from the service panel take off lugs. A better idea may be a small subpanel with a few extra spaces in it. Check local codes if you are doing this, some will, some won't allow that.>Isn't this 'essentially' doing what we've already discussed as being NOT code compliant? NO codes here, but I do want to do this in a code compliant way.What about the possibility of pigtailing the #6 house supply with #12 for the a/c, so they'd both be on the 70A main disconnect breaker? Then, the a/c would also have a 20A breaker downstream. Would that meet code, and what kind of connector would I need for the pigtail?Thanks.Thon
This is a strange area. And I am only guessing the reason why.If you have fues, then this would be no problem (unless there is someing in the code that say that they have to be next to each other). As fuse can (and typically will) blow just one side.But a fuse is not used as a disconnect. The idea is that you have not only the overload feature in the breaker, but also a SWITCH. and when the switch is thrown then the circuit is expected to be dead.Now some panel have lugs or spaces for lungs on the bus bar that allows the "panel" to be extended. To so that you need wiring and a sub-panel that is rated for the whatever the first panel is rated for (it might be that is has to be rated for main breaker in the first panel or if the first panel is a sub-panel the feeder breaker, which ever is less).I assume that you are using the QO200TR or TRNMhttp://ecatalog.squared.com/catalog/173/html/sections/01/17301019.htmlPS, ignore the list prices.The only technical problem is that it is rated for a maxinum of 60 amps and you need 70 to be LEGAL.But that panel is not only have the place for a 2 pole breaker so it is unlikely that any one put enough load on it to over load the that box.Your old panel most likely is not setup with lug space on the bus bar so that is out.I am guessing that you could legal tap the feeder to the panel, but really not sure. Doing that has the same technical problem of the disconnect only being rated for 60 amps.(BTW, the who idea of using that disconnect as an overload is probably illegal unless SQ D has listed it for such use. But you won't be the first doing this.)If you do tap the feeder then I think that there are wire nuts that you can use for that size. If not split bolts and lots of tape are available. There are also block with setscrews that can be used.So the question is which rule(s) are you going to tweak to do this.AFA overloading/fire safety I don't see much of a problem. The main one is personal safety of some one that works on this in the future. Also the AC is plugged in and not hardwired so that will be the main disconnet.And this disconnect is going to be right next to the panel so that helps.I think that the options would be to tap off the feeder (or bus bar if avaialable) then there is no expectations of a disconnect before the box. But I am not sure, went back to read the whole thread and I am confused if this box is panel is the sub-panel or not and if there is a disconnect ahead of the feeder for this box.The other is to do what you orginally wanted to do but by CLEARING INDICATING show that the two breakers feed that one disconnect.If there are holes in the handle a tag, with information on it, that has a string that goes through both breakers.Or colored tape on the side of the panel that runs up the beside the breakers and then has an arrow head point to the two breakers and at the bottom a note.The only totally correctly, clear solution would be to replace the panel.
Edited 6/11/2006 10:16 am by BillHartmann
Now I've got you guys as confused as I am! <G> What I have outside is what I called a service entrance (or service panel), and is the main disconnect for the house. It has the 70A breaker and two 30A single poles. It is from here that I wanted to run the branch for the a/c. The sub-panel, inside, which I mentioned is full, is tiny, has only 4 120v circuits, and is presumably 60+ (?) years old.No fuses in any boxes.Hope that clarifies my misleading terminology. Please let me know if that changes any of your advice.<The only totally correctly, clear solution would be to replace the panel.>I pretty much came to that conclusion yesterday. Probably wouldn't cost me much more than what I thought of doing, anyway, though from a time/aggravation stand-point it will be quite a different story.Thanks again.Thon
OK, replace the sub panel then. Should be fairly easy, and the old one is probably not so good anyway.
"Hope that clarifies my misleading terminology. Please let me know if that changes any of your advice."Not so much the terminology is it just a confusing situation.With that being the main panel then you can't tap the feeders.Other than that the other options, stand.New panel sounds the best. Not only does it solve the immediate problem, but uses breakers that you can get, etc.
Since your main disconnect is outside, your service panel is essentially a sub panel. I would seriously consider a larger subpanel. If you choose the disconnect with a breaker, I would connect it with #4 copper wire to the takeoff lugs on the old subpanel. Do not connect the disconnect with #12, as that surely would not meet any code. Local codes vary, so check them first.
I was referring to running a new disconnect from the service panel take off lugs. A better idea may be a small subpanel with a few extra spaces in it. Check local codes if you are doing this, some will, some won't allow that.
Rearange the other breakers in the panel.
Take out the the two 30 amp breakers and shift the other breakers up, down, and/or right to left until you have two open spaces one above the other. There is ussually enough slack in the wires to most breakers to allow rolling them up or down a space or two. If not just remove the wire from two breakers and make pig tail with wire nuts and some more wire to get them to their new spots.
You don't have to bother the neutrals or grounds on the the circuits you move. Just the hot wires on the breaker. If you don't feel comfortable doing this, hire an electrician. It shouldn't take himmuch more than a half hour on the job, so you will pay his minimum.
Dave