DIY Home Improvement, Remodeling & Repair Forum > DIY Home Improvement > Electrical and Wiring > number of can lights for a 20 amp breaker




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Old 03-12-2008, 02:48 PM  
adagaue37
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Default number of can lights for a 20 amp breaker

I was wanting to put some recessed can lights in my entry and hallway for better lighting. I am considering the 4' Halo cans for remodeling. I was curious as to what the the recommended number of lights on a single circuit would be. I do not have a problem to put either a 15 or 20 amp breaker in and then running the new wire to the new lights. any help would be greatly apreciated.


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Old 03-12-2008, 03:01 PM  
speedy petey
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Use the actual rating of the cans, probably 75 watts for the 4", to figure wattage.
Use the 80% figure for the circuit load for lighting such as this.

20A@120v = 2400 watts x 80% = 1920 watts 75 watts = 25 fixtures
15A@120v = 1800 watts x 80% = 1440 watts 75 watts = 19 fixtures


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Old 03-12-2008, 03:52 PM  
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Wow, thanks for that explaination speedy petey. I didn't know that was how to figure how many lights on a breaker. Very good information to know!
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Old 03-13-2008, 09:32 AM  
adagaue37
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Thanks Speedy Petey i really do appreciate the information. along the same lines if I use an existing run and it is not just lights but a mixture of lights and outlets what would the rule of thumb be on that. and if I use the fluorescent bulbs instead of the spot bulbs would you see a draw back to that? I am wanting to use the fluorescent replacements where I can to cut down on electrical usage and cost. currently 90% of the bulbs in my house are fluorescent bulbs.
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Old 03-13-2008, 02:31 PM  
speedy petey
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In a home there is no limit to the number of receptacles on a circuit. We just use common sense when figuring circuits.
I try to keep it to no more than 8-12 receptacles. If there is lighting I just compensate for it.
Using the CFLs is a good idea, just still use the actual wattage rating of the fixture when figuring circuits.
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Old 11-20-2008, 11:16 AM  
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Default Simplified Explanation

Basically your total amperage will equal your watts divinded by the volts.

AMPS = WATTS/ VOLTS

Example:

So if you were using a 20 amp breaker, 50 watt light bulb and 120 volt line, you would use the following. Remember, you want to use only 80% of the breaker capacity just to be safe and save worries later down the line.

Amps per light = 50 watt bulb / 120 volt

Each light would use .416 Amps.

80% of the 20 amp breaker would be 16 amps. Divide the 16 amp breaker by
.416 amps per light.

20 amps / .4545 amps per light = 38 lights.

Theoretically, you could use 38 lights.
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Old 11-20-2008, 06:14 PM  
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you are not allowed to use a 20A breaker for a lighting circuit in a dwelling unit (residential occupancy). It is against code (CEC). You must use a 15A breaker. It is common practise to not install more than twelve lights on a 15A breaker, regardless of the wattage of bulbs you use.
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Old 11-21-2008, 04:46 AM  
speedy petey
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Quote:
Originally Posted by fluxcapacitor View Post
you are not allowed to use a 20A breaker for a lighting circuit in a dwelling unit (residential occupancy). It is against code (CEC). You must use a 15A breaker. It is common practise to not install more than twelve lights on a 15A breaker, regardless of the wattage of bulbs you use.
Keep in mind that "CEC" stands for the Canadian electric code. We do NOT have either of these restrictions here in the US.
Considering the OP is in the US I think this is important to mention.
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Old 11-21-2008, 09:38 PM  
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Default yes 20 amp

Here in the states we can run a 15 or 20 amp lighting circuit. But not larger than that. And are only held to the max rating of all lights combined for circuit sizing, not number of them. Good luck on all your projects fellas....
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Old 10-15-2010, 05:27 AM  
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Aren't normal canned lights wired with #14 wire? Can these be used in a 20 amp circuit?


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