doin the electrical wiring in my basement
first how many lights can i put on a 15 amp circuit, using can lights and since its a basement will probably go with the max bulbs (75 watts) and wanted used the existing circuit which now has 6 light on it….. (3) in the basement (2) in the spare room and (1) in the garage. Doing the math 1800watts/75watts = 24 lights, is this correct?
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Replies
I wouldn't load the circuit more than 80% of capacity. 80% of 15 amps = 12 amps, 12 amps x 120 volts = 1440 watts, 1440 watts/75 watts = 19.2.
So, 19 - 6 = 13 additional lights, max.
My electrician likes to cut it off at 6 I think, 8 tops.
Eric
I Love A Hand That Meets My Own,
With A Hold That Causes Some Sensation.
There are two criteria for a circuit. One is that it shouldn't use more than 75% of the amp rating. The second is that you can only have a maximum of 10 items. 8 lights, 2 switches. 4 lights, 4 outlets and two switches. Etc...
Ron
Is that code or somebody's rule of thumb?
Just to clear things up, the official Code position is that there is no limit to the number of lights on a residential circuit. In commercial, however, each receceptacle outlet is 180 VA [volt-amps which =s watts].
The mathematics would be easier if we adapted a 100 volt/200 volt system.
~Peter
> The mathematics would be easier if we adapted a 100 volt/200 volt system
True, but incandescent lights would be dimmer and last a long time. Motors would run hot, and not last very long. Changing that kind of thing gets very hard when you have a big installed base.
Back in 1937, LA finally joined the rest of the country in converting from 50 to 60 Hz. They had a big program to replace or modify people's electric clocks.
-- J.S.
Here in Ontario it's code, 12 per 15A circuit, light and recep, switches don't count.
The idea I think is you could calculate your load based on 60W or 75W lamps but what if the new home owner wants to change them all to 100W.
Also recep to the outside should be on a separate circuit, on GFCI. I believe garage needs to have its own circuit too.
I hadn't heard that one before either, although it's not a bad idea to limit the number of devices on a circuit.
Tomchark brings up a good point about someone changing the size of the bulbs later, but from the original post it sounds like the can fixtures are rated at 75W max.
I also assume there aren't any other devices (outlets, etc.) on this circuit, it's just the existing lights mentioned plus any new lights.
Yeah, you should do your arithmetic based on the assumption that someone is going to come along and increase bulb wattage 25-30%. Also, for a new circuit, assume that someone will decide to add another light or two to the circuit in the future.
You could always add more cans but replace all the bulbs with compact florescents.
Yes, the next guy is gonna come along and use 100 watt incandescents but for now it'll give you alot more light.