bgott
Veteran Member
Most of the outlets and breakers I've bought lately have been marked Al/Cu. It's in little bitty print so you have to look hard.
Converting a 240v Outlet to 120v
- Thread starter MikePA
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EdKing
Platinum Member
Most breakers work by using 2 different type metal bars. The metals expand at different rates as they heat up, causing the braker to trip. The amount of heat generated is a function of the power being dissapated in the circuit. Power = Votlage x current, so 110v x 20a = 2200 watts of power. 220v x 20a = 4400 watts of power. While one side of a 220 breaker may trip at 20a, I simply don't trust it to trip in time to prevent something bad from happening. You might get lucky, and it will trip in time, but why take the chance ? In 20 years of working with electricity, and 5 years as a voluntier(sp) fire fighter, I have seen what can happen when things are "Mickey Moused" to get them to work. To me it just isn't worth the risk.
heehaw
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ok, i'm cornfused, i thought the size of the breaker was related to the size wire used??? no matter 120v or 240v?
so why change breakers?
heehaw
so why change breakers?
heehaw
Inspector507
Super Member
<font color=blue>.....Power = Votlage x current, so 110v x 20a = 2200 watts of power. 220v x 20a = 4400 watts of power.</font color=blue>
But you can't have 220v running through one side of the breaker. So you will always have 110v x 20a = 2200 watts x 2. 2200watts available for EACH phase. Most 2 pole breakers have an internal common trip, so if either phase hits the 20a mark both sides trip off
But you can't have 220v running through one side of the breaker. So you will always have 110v x 20a = 2200 watts x 2. 2200watts available for EACH phase. Most 2 pole breakers have an internal common trip, so if either phase hits the 20a mark both sides trip off
centex
Gold Member
There are two pole breakers that are no more than two single pole breakers riveted together with a pin that ties the levers together so that if one side trips the other side is opened mechanically by the one that tripped. That is the style of breaker that is used for my house. If the pin that ties the levers together is removed then you are left with two single pole breakers riveted together but electrically independent. I had to do this when the breakers became unavailable. I think there is now a source for the brand of breaker that I use but it is some third world copy that is very expensive and that I would not trust. I have spares that I stocked up on though. The two pole breakers that are molded in one body with a single lever could share a common trip mechanism but it would have to work on either pole and this type of breaker could obviously not be separated but both legs would have to be protected by the trip mechanism to allow for grounds in the load that could unbalance the legs. I can visualize a situation where a 220V load opened and one leg was grounded through the load. Since this could be either leg, the overload protection has to work for each leg independently but both legs have to be opened when the device trips.
hayden
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I don't think we ever heard what size breaker is in there to begin with. If it was a big AC unit and the 220 outlet was a 30A outlet, then the breaker will need tobe downsized, not because of the wire, but because of the new 110V outlet capacity.
Another way to state it is to check the wire size, and be sure the breaker doesn't exceed the wire or new outlet capacity. Normal 110 outlets are rated for 15A, but it's within code to wire them to a 12g, 20A circuit, so in practice the wire size sets the breaker limit. 12g = 20A, 14g = 15A.
Another way to state it is to check the wire size, and be sure the breaker doesn't exceed the wire or new outlet capacity. Normal 110 outlets are rated for 15A, but it's within code to wire them to a 12g, 20A circuit, so in practice the wire size sets the breaker limit. 12g = 20A, 14g = 15A.
fractal
Gold Member
A couple of points
1 - disclaimer - I am not an electrician - I have wired my own house according to the NEC and had it inspected and the inspector said I did everything right, but I am not a licensed electrician.
2 - your circuit breaker must be sized to protect the wire in the walls. It is OK for the circuit breaker to be smaller than the wire can handle but not more. So, the first issue is - what size is the wire? This should be written on the sheath of the wire somewhere and determines what you can do from here.
3 - I can think of two ways to solve your problem depending on how many WIRES are in the box (not how many were hooked to any plug).
3a - if you have 4 wires (usually white, black, red and bare or green), you can simply connect the white, black and bare (or green) to a 110v outlet of the appropriate rating and tape off the red wire. This is your simplest alternative and the one I would suggest if you have 4 wires in the box.
3b - if you only have 3 wires, you will have to rewire the breaker box as well. First, switch off the circuit breaker and disconnect the existing plug in the plug box. Then remove the black and white wires from the two existing 2 pole circuit breaker. Remove and reserve the 2 pole circuit breaker for later use. Add a single pole circuit breaker. Connect the hot (black) lead to the new single pole circuit breaker and the neutral (white) lead to the neutral bar. Do the same at the outlet. You will now have a 120 volt outlet properly wired.
So, in summary - find out what size your wire is and how many wires you have. Once you know that you will know what size circuit breaker you can use and whether you have to replace the breaker or whether you can use the existing one. It also tells you the type of plug you can mount in the box. Then, counting wires tells you whether you must replace the circuit breaker and rewire the pannel to get a 120 volt return to the box or whether it is already there.
1 - disclaimer - I am not an electrician - I have wired my own house according to the NEC and had it inspected and the inspector said I did everything right, but I am not a licensed electrician.
2 - your circuit breaker must be sized to protect the wire in the walls. It is OK for the circuit breaker to be smaller than the wire can handle but not more. So, the first issue is - what size is the wire? This should be written on the sheath of the wire somewhere and determines what you can do from here.
3 - I can think of two ways to solve your problem depending on how many WIRES are in the box (not how many were hooked to any plug).
3a - if you have 4 wires (usually white, black, red and bare or green), you can simply connect the white, black and bare (or green) to a 110v outlet of the appropriate rating and tape off the red wire. This is your simplest alternative and the one I would suggest if you have 4 wires in the box.
3b - if you only have 3 wires, you will have to rewire the breaker box as well. First, switch off the circuit breaker and disconnect the existing plug in the plug box. Then remove the black and white wires from the two existing 2 pole circuit breaker. Remove and reserve the 2 pole circuit breaker for later use. Add a single pole circuit breaker. Connect the hot (black) lead to the new single pole circuit breaker and the neutral (white) lead to the neutral bar. Do the same at the outlet. You will now have a 120 volt outlet properly wired.
So, in summary - find out what size your wire is and how many wires you have. Once you know that you will know what size circuit breaker you can use and whether you have to replace the breaker or whether you can use the existing one. It also tells you the type of plug you can mount in the box. Then, counting wires tells you whether you must replace the circuit breaker and rewire the pannel to get a 120 volt return to the box or whether it is already there.
There were 4 wires in the box. Red, black, white and green - the green was connected to the box. The breaker consisted of two, twenty amp breakers that were connected with a small pin. I could get the breakers apart far enough to remove the pin. After turning both breakers off, I removed the 240v outlet, connected the black and white wires to a 110v outlet, put a wire nut on the red wire and now we have another outlet in the kitchen. Thanks to all for your help!
Inspector507
Super Member
Mike,
Thats the way I wish all my little projects would go /w3tcompact/icons/laugh.gif
Jerry
Thats the way I wish all my little projects would go /w3tcompact/icons/laugh.gif
Jerry
Wingnut
Veteran Member
I did almost the same thing, Mike. I converted from an electric stove to a gas stove, and from electric water heater to gas. Left me with two 240v circuits .... so I split both into 120v and had 4 extra circuits to play with (of course, I also changed out the breakers). Made it easy to have a separate circuit for outside (they'd never completed that circuit) and for the computer room ... without complete new runs.
