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What is the minimum size wire on a 20A breaker?

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2008-08-24 01:46:39
2008-08-24 01:46:39

#12 AWG Copper. (The previous answer, "12/2 with ground", was incorrect. That answer specifies Romex. Not all homes are wired in Romex, and if they were, it would be acceptable to use any number of conductors inside the cable, including 12/2, 12/3, 12/4, and even the "new" 12/2/2.) If you receive free breakers with a "panel kit", and they are 20A breakers, keep in mind you cannot use them where a 15A breaker was previously. The wires on the 15A breakers is likely 14 AWG which can overheat and cause fire if installed on a 20A breaker. The 'weakest link' is supposed to be the breaker, not the wire. -------------- If you do not understand the work well enough to accomplish it yourself properly and safely, don't try it. Consult a professional electrician, as they are proficient enough to do it properly and safely.When working on electrical circuits and equipment, make sure to de-energize the circuit you will be working on. Then test the circuit with a definitive means to make sure it is off (multimeter with metal tipped leads, voltage tester with metal tipped leads, etc., not a non-contact tester, which is non-definitive.)

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If you have to ask here, you shouldn't be trying to wire in a 20A compressor. You will require a special circuit for the voltage and current with an independent breaker. Check your local code for the wire size or talk to a qualified electrician.

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No, this is not a recommended procedure. The breakers main job is to protect the wire that is connected to it. A 20A breaker will have a #12 wire (rated 20A) connected to it. A 30A breaker will have a #10 wire (rated 30A) connected to it. As you can see if you use a 30A breaker on a #12 wire you could overload the wire by 10 amps. I have seen an incident where the insulation has melted off of an overloaded wire, the wire short out and a fire start before the bigger size breaker tripped. DON'T DO IT.

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A #12 copper wire with an insulation factor of 90 degrees C is rated at 20 amps.

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depends on length of circuit, continuous duty or not. not knowing these factors i would say 12awg on a 20a breaker.

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You can replace a 15A outlet with a 20A outlet. However you need a circuit protected by a 20A breaker or fuse and 12 AWG wire to run 20A through the circuit.

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The 20A breaker can handle (25%) more power than the 15A breaker, because of this the wires used inside the walls is larger. Some circuits must be 20A, the laundry and kitchen are examples of 20A circuits.

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a # 12 wire is inadequate a typical 60gal electric water heater takes 20 amps this is a permanently connected permanently installed load this is too much for #12 wire it will never see less than 20A you must use the next larger size wire #10 20A fuse will blow in 20 minutes with 20A load it must be next larger size 30A fuse will protect #10 wire 25A fuse will carry 20A for indefinite period if you have several people who like to shower with warm water you will see 20A for 5 hour periods <<>> New homes will be wired for a 40 gallon tank. This will be a # 12 wire rated at 20 amps on a two pole 20 amp breaker. A 4500 watt tank will draw 4500/240 = 18.75 amps.

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150W = 240 volts * .625Amps. Assuming the 20A breaker trips at exactly 20A, 20/.625 = 32 lights.

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Technically it's a 20 amp load (20A x 240V = 4800W). However, you should not run a breaker at full load. The breaker is to protect the wiring from overheating and from short circuits. You should use 10 gauge wire and a 30 amp double pole breaker.

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Its a safety thing. 20amps on that thin of wire will heat the wire up too much. Its a fact; not a story. 14 amp wire is not ok to put on a 20 amp rated device!!!! your wire will burn before the breaker will trip and will start a fire!!!!

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In residential wiring applications the most used is 14 gauge wire for light switches as long as the circuit breaker or the fuse is 15A. If your lighting circuit is on a 20A fuse/circuit breaker then you need to use 12 gauge wire

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In a 20A double pole circuit breaker, although the breaker says 20A, the breaker is actually two 20A single pole breakers, joined together by one actuator.A double pole circuit breaker has two 120v branch circuits, hence where the 240v comes from. The two are independent 120v circuits to ground. Each branch remains electrically independent of each other, but with one common ground. Each of the two branches, on these two single pole ‘joined’ breakers, will handle 20A, for a total of 40A.For the more Technical:Ohms law causes the joined breakers to behave as if it were a 40A circuit, as far as the electrical panel is concerned, because there’ll be 40A going into the breaker, but splitting into two separate 20A circuits, or branches, of electrical current: 20A+20A=40A.Conclusion:In the past, this was easy to see because, each side was labeled with the number 20; however, more and more manufacturers are electing to control both breakers in a 20A double pole circuit breaker, with one single handle.Industrial Electronics, Computer Aided Design & Computer Aided Manufacturing

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Probably not, the pin configuration of a 30A dryer plug should be different from a 15 or 20A A/C plug. The demand draw of a dryer is higher than that a A/C unit and would trip the 15 or 20A breaker. By putting a bigger breaker on the A/C circuit would not be a good idea either because the wire size to the A/C plug would then be under sized.

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No, you're fine. Breakers are mainly used to protect the wires (and people), not the appliance. The appliance should have its own overcurrent protection (a fuse usually). The 30 amp breaker will work in this case. First off, dryer outlets are usually 30A as a standard, just like normal wall outlets are 15A. Secondly, you want your expected load to be 80% of your breaker size. So, a 20A load would call for a minimum 25A breaker, they just rounded up to the standard 30A breaker. (Which has a maximum expected load, by this rule, of 24A.) Good question though.

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Please be more specific....simply replacing the breaker with a 20 amp may cause a fire; if the cable is sized for 15 amp and is overloaded. Your 15 amp breaker is probably feeding #14 wire. The use of a 20 amp breaker requires at least a #12 wire be used. Fire hazard if breakers and wiring are not sized correctly.

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If you have 12/2 wiring in this circuit and a 20-amp breaker controlling it, you can THEORETICALLY do it, but you've got another problem: according to code, if you've got a 20-amp breaker and a 20-amp outlet, you're only allowed to have one outlet in the circuit on the theory that a 20-amp outlet is going to have a 20-amp appliance plugged into it. If you want more than one outlet, you'll need to use 10/2 wire and a 30-amp breaker.If you are asking this question, it implies you are not qualified to do the work. Hire a licensed electrician!If the breaker is not already 20A, then absolutely not! An existing 15A breaker will have #14AWG wire to the outlet(s). For a 20A circuit, you must have a MINIMUM of #12AWG. If you try to push 20A through #14 wire, you could start a fire, not to mention it is illegal.15A and 20A outlets are wired exactly the same, one just has a higher rating than the other.A regular 120V outlet is already single-phase.So, your question really is: Can an existing 15A, 120V circuit be converted to a 20A circuit by simply changing the breaker and receptacle to 20A? : No, the breaker, wiring, and receptacle(s) must ALL be changed to be safe and legal.If the breaker is already 20A, and the wiring is already #12, then no modification is necessary. You are good to go as-is.Tip: If your house has an outlet for a washing machine, check the breaker for it. Washing machines are supposed to have their own dedicated circuit, and that circuit is required to be 20A according to NEC article 210-11. You could use that outlet temporarily to do your welding.IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOBSAFELY AND COMPETENTLYREFER THIS WORK TO QUALIFIED PROFESSIONALS.If you do this work yourself, always turn off the powerat the breaker box/fuse panel BEFORE you attempt to do any work AND always use a meter or voltage indicatorto insure the circuit is, in fact, de-energized.if the wire is #12 or higher, then yes you can swap the breaker and receptacle. however, without ripping your drywall apart there is no guarantee that is #12 the entire run. back to your panel. if ihe wiring is open and you can verify its indeed 12 gauge....go for it.

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Yes, the breaker can be changed. The breaker is sized to protect the wire that is connected to it. A #10 conductor is rated at 30 amps. Any load draws what it needs to operate. It is oblivious that if the 20 amp circuit breaker is tripping then the breaker is too small for the connected load. That is probably why the #10 conductor was used in the first place. It happens quite often that if the correct breaker size is not available then a substitute is put in its place. In this case a 20 was used instead of the correct 30 amp breaker.

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Yes. The breaker can be smaller, but not larger than the circuit it is protecting. The situation you describe would normally be protected by a 20A breaker, but what you suggest is fine. You couldn't go the other direction and use a 30 A breaker because it wouldn't protect the lesser rated components.

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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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Go to your distribution panel and shut off the breaker that you think is the circuit in question. If the circuit becomes de-energized then the breaker you just turned off feeds that circuit. Look on the handle of the breaker and the number you see is the amperage of that circuit. <<>> Determination of a 15 or 20 Ampere circuit is normally indicated by a combination of a 20A breaker and a 20A dedicated outlet. A 15A circuit normally has multiple outlets; not typical in a 20A 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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Use the Watts = Amps x Volts formula. Most appliances will have the wattage on the nameplate. Nameplates that have the amperage on them will be the size of the breaker that should protect that device. There is an exception for motor loads, breaker size is 250% of full load amps. Divide the watts by the voltage and you will get the amperage of the device. This amperage will govern the size of the breaker to use. Breakers start at 15A, then 20A,30A,and 40A for most branch circuits in a house.

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A 6-20R is 220V, 15/20A correct? If the outlet is within 75ft of the panel you need to run 12-2 to the outlet from the panel. I would recommend 12-3 as you can then upgrade to a 120/240V outlet later and you are not using a white wire as a hot. If you do use 12-2 wrap the white wire with electrical tape to show it's not neutral. Then just wire the outlet as a normal 220V outlet to a 20A 220V breaker.

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A disconnected or broken wire along the path somewhere. If you have 5 outlets (in a row) on a breaker and the wire breaks at the 3rd outlet, the first two outlets will still work but the others will not. Rodents are known to gnaw on wires and that can cause the break. Or maybe a wire just came loose from a recepticle.


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