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How can you run a 240V supply into your home when the circuit breaker is 120V?

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2015-07-15 18:28:57
2015-07-15 18:28:57
for USA, Canada and countries running a 60 Hz power service.A service drop to a home is done with wire that is called triplex. This means that there are three wires twisted together that go from the service pole to the mast head on your home. This is called a three wire system. There are 2 hot legs and a neutral. The voltage between the hot leg (one) and the neutral is 120 Volts. The voltage between the hot leg (two) and the neutral is 120 Volts. The voltage between hot leg (one) and hot leg (two) is 240 volts. The single pole breaker is a safety device that connects to the (load, at 120 volts) and returns from the load back to the neutral. The load in most cases will be lights, plugs small appliances. The two pole breaker is a safety device that connects hot leg (one) to the (load, at 240 volts) and returns from the load back to the hot leg (two) at the two pole breaker. The loads in this case will be oven, range tops, hot water tank, clothes dryer, and in many homes baseboard heaters.

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In USA 240V comes into your home even though most of your equipment is 120V. I say most because your clothes dryer for one, if you have an electrically-heated one, most likely runs on 240V. The answer to your question is that 2 legs (power lines) come into your house. One leg is colored Black, the other is Red.

Each leg is 120V to common (ground). The voltage is AC (Alternating Current) so it is always going from +120V to -120V on each leg. But at opposite times, so that at some point in the cycle one leg is +120V while the other leg is -120V. And if you measure the voltage difference between +120V and -120V you get 240V.

The US wiring system works like this: to turn on your lights you switch into one leg, the current goes through your wiring to your lights and back to common. But your dryer switches into one leg and returns the current to the other leg. If you look in your breaker box you see breakers on both sides. Looking straight across, these breakers are on the same leg (L1). The next set down the panel are on the opposite leg (L2). Adjacent breakers all the way down the panel are on opposite legs. A two pole breaker spans these adjacent legs and that is how you arrive at 240 volts. Your dryer is connected to a two pole breaker that taps into both Black and Red legs.

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To accurately specify a voltage, you have to specify two points to measure, and the voltage is the difference between the two. If only one point is given it is usually implied that the second point is a grounded or 0 volt point. In the U.S., the three wires that enter most homes can be thought of as at +120V, -120V and 0V relative to ground. The 0V line is the "grounded" conductor, sometimes also called "neutral" and must be well connected to the earth where the wires enter the building (and no where else!) The +120 and -120 are actually different phases of an AC voltage wave. So by choosing which two points to connect to, a load can receive 120V or 240 V. Since there are two ways to get 120V, the breaker panel is usually set up to distribute the load between the two 120V phases.

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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,

on electrical circuits, equipment or appliances,

always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB

SAFELY AND COMPETENTLY

REFER THIS WORK TO QUALIFIED PROFESSIONALS.

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Definitely not - it would burn out quickly and probably cause the circuit breaker to trip as well.

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In America, a 2-pole breaker is controlling 240V. 120V per leg.

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A 240 volt breaker can be removed and replaced with 2 - 120 volt breakers. The existing 240 volt breaker should not be used to supply 2 separate circuits.

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If the 220V circuit is dedicated, is to derate the circuit to a dedicated 110V outlet. Replace the 220V breaker with a 110V breaker and install a 110V outlet in place of the 220V outlet. If the original circuit was 20A or greater go with a 20A breaker and a 20A outlet as Airconditioners are fairly large loads. Do not exceed the current rating of the old circuit as that is all the current the existing wiring can handle.

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Theoretically that can be done with transformers, but the power available would still be limited by the circuit breaker on the original 120 v supply.

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You have to replace the wire (as you are increasing the current capacity), the outlet, and the breaker. Essentially you have to remove the old circuit and put in a new one. You can't reuse parts of the old circuit as you are increasing the current capacity and they would be underrated.

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In simple words, NO!!! On the first day of Electricity 101 they tell you if you do not know what you are doing, DON'T DO IT!!!

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I don't know if you are trying to ask if you can run a 240V panel off a GFCI or run a 120 V sub panel off of a GFCI. Can you clarify please,,,Thanks

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In the US, both 120v and 240v will be needed for your home, as different appliances need different voltages. Your TV needs 120V, while your electric dryer and stove will need a 120V/240V supply. If you have an electric water heater, or central AC unit, they will need a 240V supply.

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On a pure 240V circuit, no. There is no neutral. On a 240/120V circuit, yes. You have the needed neutral. Tapping 120volts off an existing 240volt branch circuit with a neutral is possible but is not a proper method. It does not comply with most electrical codes.

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A far as I know, you can't. If a wire is used in a 120v circuit, the wire itself is only rated up to 15 amps, therefore it can't carry a full load without tripping the breaker.

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Yes, otherwise your double pole breaker will shut the other circuit off when one of them trips.

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No, you must break it down to a 120 volt supply.

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Assuming a 120V circuit then a 30A Single Pole. For a 240V circuit an 30A two pole. Of course anything smaller that a 30A is acceptable. 30A is the maximum allowed.

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A single pole 15 amp breaker can only be setup for 120v. You need a double pole 15 amp breaker, which looks like two 15a breakers attached with a bar across the two actuators. Each leg provides 120v, or in the case of your breaker, 240v across the two legs.

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The voltage has nothing to do with the gauge of wire needed to supply a given circuit. The size wire is determined by the amperage of the overcurrent protection device (circuit breaker, etc.) being used to supply power to the circuit.

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A two pole 20A circuit breaker can be used for any 240V load that requires 20A, with supply conductors no smaller than 12AWG. Since a clothes dryer typically requires 30A, and a range 40A to 50A, a 20A 240V circuit could probably be a window air conditioner, pool pump, or some other 20A 240V load.

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Answer for USA, Canada and countries running a 60 Hertz supply service.Yes, a 240v 50amp circuit can be changed to a 120v 30amp circuit. The wire for the 50 amp circuit should be a #6. This is more than ample for a 30 amp circuit. Remove the two pole 60 amp breaker and replace it with a single pole 30 and a single pole 15 amp breaker. One of the two #6 wires will be terminated on the neutral bus (if there is a white use it) and the other #6 will be terminated on the new 30 amp breaker. This will give you the required 120 volt 30 amp circuit. The new 15 amp breaker that was installed just to fill the hole from the two pole 60 amp breaker will give you a spare 15 amp circuit. >I have no idea what you are trying to do, but there is no way you can change 220v 50 amp to 120v 30 amp. You can take 220 volt input in the top of your circuit breaker box. Then half of one side will be 120v and half of the other side will be 120v. You can install a 30 amp fuse. You should hire an electrician.Before you do any work yourself,on electrical circuits, equipment or appliances,always use a test meter to ensure the circuit is, in fact, de-energizedIF YOU ARE NOT REALLY SURE YOU CAN DO THIS JOBSAFELY AND COMPETENTLYREFER THIS WORK TO QUALIFIED PROFESSIONALS.

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For a 7000watts or 7kw a 240V then it is 30 Amp

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Answer for the US: Breakers are rated in amps, not watts. However, a 15A breaker can handle 15 amps, or about 1800 watts (using 120V), or 3600 watts (using 240V). However, this is only rated for noncontinuous loads (those not lasting for more than three hours). For continuous loads (loads lasting three hours or more), one must derate the circuit breaker by 80%. So for continuous loads, that same breaker should only have 1440 watts (using 120V), or 2880 watts (using 240V) on it.

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It can't be "converted", you have to run a 220 line and have a 220 breaker and plug installed.

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Have an electrician wire you a proper line for the appliance. You were just kidding about the 100A, right? 10, or 20amp, not 100.

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You have three feed wires on US residential service: 2 hots and neutral. These wires are connected to a 240V center tapped transformer with the neutral connected to the center tap. So, you have 120V between either hot and neutral and 240V between the hots. There is no neutral in this circuit because the load doesn't require 120V, it draws 240V directly from both hots.

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For USA, Canada and countries running a 60 Hz supply service.1) An outlet for 240V is totally different from a regular 120V outlet. 2) The wiring for 240V is also much heavier than for 120V.3) The double pole circuit breaker necessary for 240V is different to the single pole breaker used for 120V.4) Anyway it is not clear why you would want to try to change a 240V outlet to a 120V type?5) If you could log in and add some more details below here so we knew your reasoning for wanting this change to take place, someone may be able to assist you much further.The reason why I need to do this is because there is only one 3-prong 240V outlet in the water heater closet feeding an inline water heater and I want to install an instant hot water recycling system which runs on 120v I so need the extra power outlet.If you want to keep the existing 240V water heater then you cannot add another outlet to the circuit, not even a 240V one, let alone a 120V one!The wiring and its circuit breaker is only rated to carry the current for one water heater and nothing else. If you add another appliance to the circuit you risk causing a house fire: the breaker may buzz but not trip so that the wiring gets hotter and hotter until something catches on fire!So, if you are planning to buy a new hot water recycling system it surely deserves to be installed safely and correctly?So why not, for your instant hot water recycling system, have a licensed electrician install a separate 120V circuit with the correct breaker, the correct-sized cable and the correct outlet near to the existing 240V outlet?As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.Before you do any work yourself,on electrical circuits, equipment or appliances,always use a test meter to ensure the circuit is, in fact, de-energized.IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOBSAFELY AND COMPETENTLYREFER THIS WORK TO QUALIFIED PROFESSIONALS.


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