# how many lights in a circuit as per code

Discussion in 'Electrical and Wiring' started by pedrito, Oct 3, 2010.

1. Oct 3, 2010

### pedrito

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It is my intention to place 24 pot lights around

the perimeter of the house.

24 lights of 50 watts, having of total of 1200

watts.

1200 watts divided by 120 volts gives me 10 amps.

I have placed a new breaker of 15 amps. Wich lead

me to think that I will be OK.

The question that I have is: How many lights I am

allowed asper code in one circuit.

IT is 12 lights ONLY????

2. Oct 3, 2010

### mudmixer

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Your calculations based on planned bulb sizes are worthless if some one decides to use 60, 75, 100 or 150 watt bulbs. That is why they have codes to protect future owners or you from yourself if you decide to change the size of bulbs in the future. What if you decide to add a ceiling fan with 4 bulbs next month?

An electrical professional or an electrical inspect could help you because I am not that familiar with the details, but I do know what makes sense.

Dick

3. Oct 3, 2010

### delstu

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It depends on local codes. In most cases it is not the number of lights but the total load on the circuit. There is probably a percentage of circuit capacity allowed but not being an electrician I don't know the percentage.

4. Oct 3, 2010

### JoeD

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The limit of 12 is in the Canadian code code. However if it is lights only the limit can be exceeded if you use the max wattage of the fixture and keep it under 80% (1440 watts). It must be only lights. There can be even on receptacle or you are limited to 12.

5. Oct 3, 2010

### ceclmc

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You can load a circuit up to 70% continuous load. The number of lights is really not important as long as you size the circuit accordingly. It works out that way for receptacles also. You have no control over how many things someone will plug in to them you just have to size the breaker and wire correctly so that it doesn't present a fire hazard. Just as you cant control what size light bulbs someone installs, you have to size the circuit so that the breaker will protect the size wire that you install. A 15 amp breaker and #14 wire should work nicely for your project. You will not exceed the 70% continuous load.

Chuck

6. Oct 4, 2010

### speedy petey

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First off, it is 80% in the US for a continuous load, not 70%. Also, in a residence, receptacles and lighting are taken into account in the demand load calc. There is NO limit to number of lights or receptacles on a circuit.
That said, if you have a circuit with many lights it is obviously a good idea to size it according to the amount of lights that will be used at the same time.
Outdoor or security lighting are some of the few things in a residence that would actually be considered a continuous load.

7. Oct 4, 2010

### JoeD

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The OP is in Oshawa. In Canada we have a limit of 12 outlets on a circuit with the exception of a lighting only circuit where can use the max wattage value of the fixture to calculate the number of fixtures.
Also lighting must be a 15 amp circuit. You are not permitted to put lighting on a 20 amp circuit.

8. Oct 5, 2010

### speedy petey

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Wouldn't it be SO nice if folks put that information there from the start.

9. Oct 7, 2010

### hornetd

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Chuck
Do you want to explain were you got that seventy percent (70%) figure.
--
Tom Horne

10. Oct 8, 2010

### ceclmc

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Per the NEC 210.19 Over current protection devices are supposed to be sized for 125% of continuous current, which means that they are expected to carry continuously 80% of rated current.

I made a mistake when I put 70%.

The corresponding rule for over-current protection is given in NEC 210.20(A). It states that the Over current protection device rating is to be not less than the noncontinuous load plus 125% of the continuous load.

According to the definition in Article 100, continuous load means that it continues for 3 hours or more.

I hope that clears up my mistake. Sorry

Chuck

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11. Oct 8, 2010

### hornetd

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Chuck
Thank you. I was concerned that the committee had adopted a new lower standard.
--
Tom Horne

12. Oct 8, 2010

### speedy petey

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Just a small clarifications, but one that is pretty important.

A continuous load is one where "A load where the maximum current is expected to continue for 3 hours or more."

Very little in a home would actually be considered a continuous load. Some things, like electric heat and water heaters must be considered a continuous load, but I am referring to lighting and receptacle circuits.

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