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What size of circuit breaker should you use for a lighting circuit?
Wiki User
∙ 14y ago
To correctly size a lighting circuit, you must know the total power that the circuit will draw, in watts. For example, if there is 7 lights on a circuit, each light consumes 100W, that gives you a total of 700W on the circuit. Then you must know the voltage that is being supplied to the circuit. For this example, 120VAC will be used. To calculate the current needs for sizing the breaker, use the formula P=E*I, where P=watts, E=voltage, I=current/amps. So, in this example, P=700, E=120, I is unknown. After working the formula, you have an answer of 5.83 A. Breakers generally come in sizing increments of 5A.....5A, 10A, 15A, 20A, etc. The answer for this example was 5.83A, so the 5A breaker is obviously not enough. The next size is 10A, which is more than the calculation, but you must also consider that breakers are designed to operate at 80% capacity for periods of time over about 3 hours. So for an office atmosphere where the lights will definitely be on for longer periods of time than residential (in most cases), you would need to make sure that the total Amps needed is equal to or less than the 80% of the breaker size you have chosen. A 10A breaker is only designed to provide 8A of capacity for longer periods of time. So for this example, a 10A circuit breaker would be properly sized. You must also abide by the NEC code for maximum number of fixtures on any particular circuit. Refer to NEC for that information. If you were to change the light fixtures to a larger size, such as 200W each, you would then find that you need to also change the breaker and possibly the wire size that is run through the circuit, to maintain compliance with NEC.
Wiki User
∙ 14y ago
Wiki User
∙ 10y agoA breaker is sized indirectly by the load current. The breaker is used to protect the wire from being overloaded by amperage. Wire is sized by the load amperage. The procedure is, use the load amperage to find the correct wire size that will carry that amperage safely. Size the breaker so that the amperage on the wire doesn't exceed the rated capacity of the sized wire.
The only time a breaker is over sized above the wire's rating is when a motor is connected into the circuit. Then the breaker is over sized by 250% of the motors full load amperage. This is to compensate for the starting current of the motor which can get as high as 300% above the motor's run current.
Wiki User
∙ 15y agoIt's the wiring that determines the max amps.
14 gage - 15 amp (or less)
12 gage - 20 amps (or less)
Wiki User
∙ 12y agoTypically residential and many commercial applications use a 15 amp service for lighting circuits. They use 14 AWG wire.
Wiki User
∙ 11y agoThis is set-up by the "National Electric Code", which says; 14 gauge wire, 15amp. 12 gauge, 20amp beaker, ect.
Wiki User
∙ 15y agoWire size is governed by the load ampacity.
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What is the standard to select circuit breaker?
Add up your amps to calculate your breaker size. Add up your loads (amps), divide by 0.8, and choose that size breaker. If that number does not correspond to a standard size breaker you go to the next higher standard size breaker.
Is the main circuit breaker is a sum of the sub circuit breaker?
Typically yes because that is what makes sense. However, the subpanel could have the same size breaker as long as the panel were rated for that amperage and the wire sizes were appropriate.
What type of circuit breaker is required for a 240 v branch circuit?
the circuit breaker used will be miniature circuit breaker(MCB) maily used in homes.Answer for USA, Canada and countries running a 60 Hertz supply service.A two pole circuit breaker is used for a load of 240 volts. It is sized, according to the load amps of the device, to protect the wires that supply the load current.
If you're installing a circuit that will contain receptacles in an industrial area and the first receptacle is more than 50 feet (15.24 meters) from the load center you should?
Connect the circuit to the appropriate size circuit breaker to meet the required amperage of the circuit. Turn the breaker on and use the circuit. Unless the circuit is of a very high ampacity, plus 200 amps, don't worry about voltage drop over 50 feet.
What breaker size do you use for a 270 Kw power rated equipment and power supply of 380 vac 3 phase?
I=270000/380/1.732 I=410A USE: 500A CIRCUIT BREAKER
How are Branch circuit protected?
Branch circuits are protected by the circuit breaker found in the electrical panel. Each circuit should have its one breaker. The breaker should be rated to protect the insulation of the wire, so you can determine the breaker size based on the circuit conductor size Example #14-2 should be protected by a 15 amp breaker
When installing a circuit breaker do you size the breaker to correct wire size or the device its controlling?
When installing a circuit breaker, you size the breaker based on the wire size. The breaker should be matched to the ampacity of the wire to ensure proper protection against overloads and short circuits. The device being controlled by the breaker is not a determining factor in sizing the breaker.
What size amp circuit breaker should be used for a home entertainment system?
You use the correct size breaker depending on the size wire in the circuit. If the circuit is wired with AWG #12 wire use a 20 amp breaker. If it is wired with AWG #14 wire then use a 15 amp breaker.
What size circuit breaker should be used for dishwasher and disposal?
A 15 amp dedicated circuit breaker should be used for the dishwasher. The disposal can be wired to the general kitchen 15 amp circuit.
What size amp circuit breaker should be used for a geyser?
Depends on how many amps it pulls and the size of the wire in the circuit.
What size amp circuit breaker should be used for a pool light?
The pool light is usually on a 15 amp circuit. The breaker feeding this circuit must have a GFCI rating.
What size amp circuit breaker should be used for 110 outlet?
The size breaker you use is determined by the size wire used in the circuit. If you use AWG #12/2 wire then use a 20 amp breaker. If you use AWG # 14/2 then use a 15 amp breaker.
Can a circuit breaker be tripped by using 20 amp sockets instead of 15 amp sockets?
A circuit breaker protects the wires that the devices are connected to. If the devices that are connected to the circuit are 20 amps the wire size should be #12 wire fed from a 20 amp breaker. This breaker should not trip unless the circuit is overloaded or a fault occurs on the circuit. If the devices that are connected to the circuit are15 amps the wire size should be #14 wire fed from a15 amp breaker. This breaker should not trip unless the circuit is overloaded or a fault occurs on the circuit. Putting 20 amp sockets on this 15 amp circuit will work but the circuit is limited to the amount of load that can be plugged in. You will not get the full capacity of the 20 socket because the breaker will trip at 15 amps.
What size in amperage circuit breaker should be used for a pool pump?
The sizing of the circuit breaker and hence the wire size to feed the pump are all dependant upon the amperage of the pump. This question can not be answered without that information.
A small appliance circuit will be protected by a circuit breaker rated at?
Yes, it will be protected by a circuit breaker or fuse. The normal rating of the circuit breaker or fuse is 25% more than the maximum current expected, or the maximum current allowed for the cable size, whichever is lower.
What is the standard to select circuit breaker?
Add up your amps to calculate your breaker size. Add up your loads (amps), divide by 0.8, and choose that size breaker. If that number does not correspond to a standard size breaker you go to the next higher standard size breaker.
How do you know if the AC breaker matches the AC unit starting demand load?
Read the literature for the ac condensing unit, or the tag on the outside of the unit. Minimum circuit ampacity= minimum breaker, wire and fuse size. Maximum circuit ampacity= the maximum size. Your circuit breaker, wire size and disconnect fuses should all be at or between those 2 numbers.
