Overhead Garage Lighting electrical ?'s

[desjr]

I just finished a 36x60 building with a 14' ceiling, and am now starting to wire it up. Got a 200 amp service all ready installed to the building. I am going to use 12 lithonia 3 bulb florescent fixture. The specs on these are 35 watts per bulb, but the rating on the fixture itself is 85 watts, which makes no sense to me.

I am planing on running these on either 3 or 4 switch legs, on 20 amp breakers with 12\2 with ground wire. One may be a 3 way, not sure if I need it yet or not.

My calculations, if I am doing this correctly is that regardless of the wattage (85 or 105) per fixture, I have plenty of capacity for each circuit with no worries.

From what I see, I could potentially put all 12 fixtures on one 20a circuit and still be good.

BUT, I like to play it safe and check to be sure.

The fixtures are Lithonia LB 3/32MVOLT 1/3 GEB10IS lamps are 48" T8

Thanks for any and all help.

 

[wsmith8604]

By figuring these fixtures at 105w per fixture you will only have 1260 watts which will equal out to 10.5amps at 120volts....you only are supposed to load a breaker 80% of its rating which on a 20 amp will be 16amps....so yes you will be perfectly fine by doing that...imo i had rather use a 30amp just incase you want to or end up having to add more lights...always plan ahead on stuff like that...and dont buy the cheap switches pay a little bit extra on the front end amd save you from having to swap out later

 

[cybrdyke]

85 is the correct number for watts consumed by this fixture.
CD

 

[wsmith8604]

Even better....your only at 8.5 amps

 

[desjr]

Thanks for all the help everyone. Much appreciated. Hope to be able to return it some time.

Duane

 

[pattenp]

...imo i had rather use a 30amp just incase you want to or end up having to add more lights...

You can't put typical lighting on a 30A circuit unless the lamp holders are rated as heavy-duty. I doubt very much the OP will ever be using lighting that meets the requirements for being on a 30A circuit.

 

[cd36]

Where are you located? If in Canada I don't think you can even put them on a 20 amp circuit, 15 is max for lighting.

Sent from my HTC One using Tapatalk

 

[desjr]

The lights will be on either 3 or 4 circuits, depending on how I switch them. 1 switch for one circuit which will control 3 or 4 lights per circuit, daisy chained. never intended to put all 12 on one circuit, all though mathematical I could. The amount of fixtures as stated in the original post was and still is 12.

 

[wsmith8604]

You can't put typical lighting on a 30A circuit unless the lamp holders are rated as heavy-duty. I doubt very much the OP will ever be using lighting that meets the requirements for being on a 30A circuit.

NEC sizing rules. Secs. 210-22(c), 220-3(a), 220-10(b), and 384-16(c) all relate to the sizing rules for overcurrent protective devices (OCPDs).*@#$

 

[wsmith8604]

Ignore the *@#$...i have no idea why my phone did that

 

[pattenp]

NEC sizing rules. Secs. 210-22(c), 220-3(a), 220-10(b), and 384-16(c) all relate to the sizing rules for overcurrent protective devices (OCPDs).*@#$

What NEC are you reading from? In the 2011 NEC there is no 210.22 section. NEC 2014 210.22 was added but there is no (c). There is no 220.10(b) either. Read from NEC 2011 or 2014, section 210.23 (b) for 30A circuits.

 

[wsmith8604]

What NEC are you reading from? In the 2011 NEC there is no 210.22 section. NEC 2014 210.22 was added but there is no (c). There is no 220.10(b) either. Read from NEC 2011 or 2014, section 210.23 (b) for 30A circuits.

You are right....sorry i was looking at another forum that was talking abt similar topic and thats what one guy postd...but i did look up the 210.23 and still didnt see where its against code to put a lighting circuit on a 30 amp or where it would have to be hd fixtures (it may sound like im being a butthead but im seriously not)

 

[pattenp]

You are right....sorry i was looking at another forum that was talking abt similar topic and thats what one guy postd...but i did look up the 210.23 and still didnt see where its against code to put a lighting circuit on a 30 amp or where it would have to be hd fixtures (it may sound like im being a butthead but im seriously not)

I didn't say you can't put lighting on a 30A circuit. The type of lighting is restricted to lamp holders that are rated heavy duty. You see a lot of commercial lighting that's on 30A circuits, such as parking lots. Also read 210.21(a). Typical residential lighting does not meet the required watt rating for the lamp holder to be on a 30A circuit.

 

[wsmith8604]

I didn't say you can't put lighting on a 30A circuit. The type of lighting is restricted to lamp holders that are rated heavy duty. You see a lot of commercial lighting that's on 30A circuits, such as parking lots. Also read 210.21(a). Typical residential lighting does not meet the required watt rating for the lamp holder to be on a 30A circuit.

Oh ok gotcha...im sorry if i came off as a jerk

 

[pattenp]

Oh ok gotcha...im sorry if i came off as a jerk

I didn't see anything that you said would make me think that you were coming off as a jerk. We were just having a friendly debate.