Number of switches/circuit?

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ElectDesigner

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Ontario, Canada
We use 347V circuits for lighting in most buildings (in Canada), so most of the time we only need one or two breakers to cover lighting for a certain floor. I would just like to hear from the electricians/ contractors what it the maximum number of light switches that is practical per lighting circuit? and why? For example say you have a floor with multiple small offices let say 30 offices, assume the lighting loads in the offices is below the maximum allowed by code, would you prefer a single circuit with 30 switches or maybe two circuits with 15 each. Im just trying to figure out what is the most economic way of going about it.
 
Joethemechanic

Joethemechanic

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Location
Hazleton Pa
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Electro-Mechanical Technician. Industrial machinery
I still don't understand what the OP is trying to do. Is he trying to control 30 different groups of lights? All on one circuit? What would you do when you need to shut off one office to do repairs?

I got to tell you, getting bit by 277 is bad enough, 347 could seriously hurt you in a hurry.
 
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maghazadeh

Senior Member
Location
Campbell CA
ElectDesigner said:
We use 347V circuits for lighting in most buildings (in Canada), so most of the time we only need one or two breakers to cover lighting for a certain floor. I would just like to hear from the electricians/ contractors what it the maximum number of light switches that is practical per lighting circuit? and why? For example say you have a floor with multiple small offices let say 30 offices, assume the lighting loads in the offices is below the maximum allowed by code, would you prefer a single circuit with 30 switches or maybe two circuits with 15 each. Im just trying to figure out what is the most economic way of going about it.
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I don't think econmicly there is any different to go 30 sw 1 circuit via 15 sw 2 circuit.
But having 30 offices you need min. 30 sws. there is going to be corridors to these offices they should be switched seperately from offices.
Here in California we have laws called Title-24 (Energy conservation) which lighting load is part of it. If there is offices larger than 100 sq. ft. there shall be 2 sws min. per office and so on......etc... If your bldg. was here you had to start with 60 sws just for the 30 offices.
 
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ElectDesigner

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Location
Ontario, Canada
Thanks for the replies, I'm sorry if I was vague in my OP. Let me try again, so you have an office floor - all the corridors and reception areas have their own lighting circuits. So now we need to provide lighting for the offices, I can run the lighting for all the office room from one single 20A breaker (347V x 20A x 0.8 = 5552W available ) so say two 32W double lamp T-8 fixtures per room (2x32W x 2fix/room x 30rooms = 3840W ) so load wise we can feed all the office rooms off one 20A circuit. And lets assume each office room has one switch, so from panel "A" position 1 (20A breaker), our lighting circuits will be A.1.1, A.1.2, A.1.3 .....A.1.30 - in this case we have 30 switches off one breaker (or 30 parallel circuits). My question is from an installation point of view what is the practical limit on number of switches/parallel circuits off a single breaker ? Im just trying to figure out if there is any practical limitations to this approach? Keep in mind this is just a scenario not a real situation. Surely from a servicing point of view having more circuits for the offices would make sense as you dont want to cause a complete blackout - but also you don't want to be in a situation where you use 3 or 4 breakers that are only loaded to say 20% capacity - this would mean more breakers -more cost?.

Hopefully Im clearer this time. :huh:
 
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