Running 240 with 120

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agezzi

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What is the break down on running 240v element on 120v. I know you can, but what is the the break down. Like what would a 3500w 240v element put out watt wise on 120v.
 
So it just cuts it in half? I have seen a thread before on the break down. But I can't find it.
 
Wait... Wait..

An element rated for 240V and powered by 120V delivers 1/4 the wattage.
The 3500W 240V element powered with 120V delivers 875W.
 
The entire commonly available series of 240V elements breaks down like this:

6000 Watt on 240V = 1500 Watt on 120V
5500 Watt on 240V = 1375 Watt on 120V
4500 Watt on 240V = 1125 Watt on 120V
3500 Watt on 240V = 875 Watt on 120V
2000 Watt on 240V = 500 Watt on 120V
 
It is probably too pricey but is it feasable to use a step-up transformer to power the 240V elements using standard 120V/20A power?

This would solve the impedence mismatch and you would get all the power from the 240V element.
 
Transformers that size cost silly money. And you'd still be limited to the current rating on the 120V circuit.
 
Can you move your neutral on that outlet to another breaker? If you can u now have 240.
 
It is probably too pricey but is it feasable to use a step-up transformer to power the 240V elements using standard 120V/20A power?

This would solve the impedence mismatch and you would get all the power from the 240V element.

To step-up to 240v 30A you would need 120V 60A. You can only get 240V 10A from a 120V 20A circuit.
 
Can you move your neutral on that outlet to another breaker? If you can u now have 240.

In principle, this can work, but you need to verify a couple things to do it safely when adding a breaker and powering the white as a second hot leg.

1) If there is more than one outlet on the circuit, and you rewire just one for 240 V, you run the risk of frying any 120 volt equipment plugged in elsewhere.

2) The wire gauge between the breakers and the receptacle will determine the maximum wattage of the element you can use.

If its 14 gauge like most home receptacles, it is limited to 15 amps of current. 240 V x 15 A = 3600 watts

If its 12 gauge like some home receptacles, it is limited to 20 amps of
current. 240 V x 20 A = 4800 watts.

3) Regardless of the voltage, 120, 240, or whatever, the wire size determines max. current. The circuit breaker has to be sized to the wire size, because the breaker protects the wire from an over-current condition.
 
In principle, this can work, but you need to verify a couple things to do it safely when adding a breaker and powering the white as a second hot leg.

1) If there is more than one outlet on the circuit, and you rewire just one for 240 V, you run the risk of frying any 120 volt equipment plugged in elsewhere.

2) The wire gauge between the breakers and the receptacle will determine the maximum wattage of the element you can use.

If its 14 gauge like most home receptacles, it is limited to 15 amps of current. 240 V x 15 A = 3600 watts

If its 12 gauge like some home receptacles, it is limited to 20 amps of
current. 240 V x 20 A = 4800 watts.

3) Regardless of the voltage, 120, 240, or whatever, the wire size determines max. current. The circuit breaker has to be sized to the wire size, because the breaker protects the wire from an over-current condition.

Well if he didnt know that every thing on that circuit would be 240, than he probably shouldn't do his own electrical. But either way he is fine at getting what he needs.
 
Can't just connect it to any old breaker either. Has to be on the opposite leg and the two breaker handles must be tied for common trip. By rights the grounded wire has to be marked to indicate it's a hot wire, and the receptacle has to be changed to a 240V style.

I agree about not doing the wiring if you don't know about wiring but by the same token just throwing something out there that is potentially dangerous is not prudent either.
 
Can't just connect it to any old breaker either. Has to be on the opposite leg and the two breaker handles must be tied for common trip. By rights the grounded wire has to be marked to indicate it's a hot wire, and the receptacle has to be changed to a 240V style.

I agree about not doing the wiring if you don't know about wiring but by the same token just throwing something out there that is potentially dangerous is not prudent either.

Isnt most electrical stuff dangerous? Lmao
 
Can you move your neutral on that outlet to another breaker? If you can u now have 240.

Great way to start an electrical fire. It isn't that much more trouble to do it right and be safe about it. Besides, if you have room in your panel for two 120V breakers, you have room to swap those out with a 240v breaker. Breakers are relatively cheap, like 10 bucks or less.
 
I'm installing a 5500W element.

Is 1375W enough to maintain a 5 gallon boil? If so, that means I could have a simple switch to switch my element from 240V to 120V (using the neutral wire) when my beer reaches boil. That would be a very simple control setup.
 
Great way to start an electrical fire. It isn't that much more trouble to do it right and be safe about it. Besides, if you have room in your panel for two 120V breakers, you have room to swap those out with a 240v breaker. Breakers are relatively cheap, like 10 bucks or less.

How is he going to start an electrical fire by switching the neutral to a hot?
 
I'm installing a 5500W element.

Is 1375W enough to maintain a 5 gallon boil? If so, that means I could have a simple switch to switch my element from 240V to 120V (using the neutral wire) when my beer reaches boil. That would be a very simple control setup.

You can install a 3 way switch to connect one side of your element to neutral or the other hot leg. The common - off colored screw goes to the element and the other two screws go to neutral and the other hot leg.

The trick will be finding a 3 way switch that's rated for 240V & 23 amps. You won't find one at Lowes or Home Depot. You will burn out a standard house lighting 3 way switch.
 
You can install a 3 way switch to connect one side of your element to neutral or the other hot leg. The common - off colored screw goes to the element and the other two screws go to neutral and the other hot leg.

The trick will be finding a 3 way switch that's rated for 240V & 23 amps. You won't find one at Lowes or Home Depot. You will burn out a standard house lighting 3 way switch.

They actually have cheap 30A switches, but they aren't 3-way. I might use one of these as a 'master off' switch for my panel:

http://www.homedepot.com/p/t/100356...toreId=10051&N=5yc1v&R=100356941#.US0O91cpFck
 
Oh yeah my advice was real reckless but good try tho.

The OP asked what the wattage would be running a 240v element at 120v.

You responded to someone who is obviously not well versed in electric circuits, "Can you move your neutral on that outlet to another breaker? If you can u now have 240."

You included no disclaimers around exceeding the capacity of the circuit, marking a neutral wire that is now hot, understanding how to achieve it with split phase 240v, not undertaking it without the requisite knowledge or the help of an experienced electrician, etc.

If the OP had just gone ahead and done it, shame on him. I will not judge whether you were reckless. However, you were quite cavalier about suggesting an approach that was probably not going to be very helpful given the existing wire gauge on the 120v circuits, and could prove quite dangerous for a novice to undertake.
 
You can install a 3 way switch to connect one side of your element to neutral or the other hot leg. The common - off colored screw goes to the element and the other two screws go to neutral and the other hot leg.

The trick will be finding a 3 way switch that's rated for 240V & 23 amps. You won't find one at Lowes or Home Depot. You will burn out a standard house lighting 3 way switch.

http://shopping.yahoo.com/771707327...ade-self-grounding-back-and-side-wired-ivory/
 
I'm hesitant to add anything that may confuse the installation even more, but I vote for that 2-pole 240V breaker to be a GFCI type, since we're dealing with (wet) environments? It may also be code in many localities.

I had a whole house's electrical system run through the oven elements because of a non-tied 2-pole fuse setup (buss fuses). Speaking of an unintentional rheostat.

IMO, bridging phases, reassigning wires, etc., should be left to people who really know what they are doing and do so only in extreme cases as temporary patches, when there are no other options.

To help the OP, I know from experience that a 750W element (only 75W less than the 1/4 powered 3500W one) does not have enough power to heat even a few gallons of water to boiling point or even keep them boiling.
I have a 750W self-contained "heat stick" with built-in thermostat and although 120 degrees is the maximum setting it is also about the limit of its heating capacity to keep up with the heat loss at that temperature in a metal tank.

Even 1500W may be too skimpy. YMMV.
 
Just for comparison, a standard stove burner is rated at 2400w.
Since a stove burner it is not immersed into the liquid, i would say you only get about 50% efficiency whereas an immersion heater u get 100%, or close to.
 
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