Lighting circuit for tech school.

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Crabcakes&football

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I have an extra credit assignment for school, we have a scenario dealing with the lighting circuit. We have 23 lights that are 200 watts each, at 120 volts. We have 2 single pole switches, one switch controlling 10 lights and the other controlling 13 lights. Since each light draws 1.6 amps I can only put 10 light on a 20 amp circuit, 80% of the breaker load. Either this is a trick question or I the answer is go with a 30 amp breaker.
 
Is the question asking you to figure the scheme? Do you have constraints to stay within or can you do anything as long as its code compliant?
There's ways to switch a load without that load running through a switch.

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We were given how many lights to use and their watts.and how it's switched. The task is to setup ,breaker, wire size. Since there's 2 switches I'm think each switch will be it's own circuit. But then I came across one switche will have 23 lights on it. Also forgot to add there are 2 with emergency ballast ,1 night light and 2 exit signs.
 
You keep adding to the question. Can you post the actual question with all the information. We need to know things like, are the lights a continuous load? Are you limited to a certain size breaker?
 
Little Bill said:
You keep adding to the question. Can you post the actual question with all the information. We need to know things like, are the lights a continuous load? Are you limited to a certain size breaker?
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We have 22 lights that are 200 watts each, at 120 volts. We have 2 single pole switches, one switch controlling 10 lights and the other controlling 12 lights. Since each light draws 1.6 amps I can only put 10 light on a 20 amp circuit, 80% of the breaker load. The task is to setup ,breaker, wire size. Since there's 2 switches I'm think each switch will be it's own circuit. But then I came across one switche will have 22 lights on it. Also forgot to add there are 2 lights with emergency battery ,1 night light 24/7 and 2 exit signs.
 
Crabcakes&football said:
We have 22 lights that are 200 watts each, at 120 volts. We have 2 single pole switches, one switch controlling 10 lights and the other controlling 12 lights. Since each light draws 1.6 amps I can only put 10 light on a 20 amp circuit, 80% of the breaker load. The task is to setup ,breaker, wire size. Since there's 2 switches I'm think each switch will be it's own circuit. But then I came across one switche will have 22 lights on it. Also forgot to add there are 2 lights with emergency battery ,1 night light 24/7 and 2 exit signs.
Click to expand...
Now you saying 22 lights and you started out with 23 in your OP. I don't think you would need to include the EM ballast, night light, and exit since they won't be switched.
 
Little Bill said:
Now you saying 22 lights and you started out with 23 in your OP. I don't think you would need to include the EM ballast, night light, and exit since they won't be switched.
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It's 22, I corrected it. That's correct, my main question is with all those lights at that wattage, 2 20 amp circuits won't be enough. If I put each switch on its own circuit.
 
I've heard in that past lighting circuits at one time could be on a 30A breaker, never did it myself, It may of been for 277/480.

Not to confuse matters though, This is were me and the text book would clash.

In my world 20A x 120v = 2400w 2400w/200w lights = 12 lights I wouldn't want a breaker to operate at 100% even though they can, but why push it. so use your 80% now were at 10 lights .. Bottom line you now know you can safely operate 10-200w lights with 1-20a circuit per design.

Lets say the 2 exits are another 200w ea .... 400w
23 lights at 200w .................................................4600w the emergency ballast or night light wouldn't really add anything.

total 5000 w / 120 = 41.66A

Either 3 Circuits using as mentioned above 1-two pole and 1- single pole switch or
2 single pole switches controlling 2 coils of 2- pole contactors.

That would be my resolve.
 
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