277 volt vs 120 volt lighting

If the building has a 480V/277V service and you have a lot of lights to install, then the contractor can use smaller wire with 277V lighting but will have to use more expensive lighting panels. Also you will not be putting the extra current load on your existing step down transformers if you use 277V.

I would talk to the contractor and the owner and ask them each to present thier case. As far as the lighting goes, there really isnt much difference. 120V installations tend to be cheaper and safer if you have enough power at that voltage.

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And conversely, if you don't already have a 480/277V service, 277V lighting make no sense at all. It is mainly a convenience for facilities that have 3 phase 480V 4 wire service because phase to neutral is 277V, so no transformer is needed. If your facility has 1 phase service, or 208V 3 phase service, then 120V lighting is what you want. The electrician probably already knows this. The owner probably has no clue.

The building does have 3 phase 480 volt...so a transformer is needed but whether 277V or 120V lights a transformer would be required. Correct? Is there a cost savings on initial cost of 277V lights vs 120V lights? Is there life cycle cost savings? Thank you.

Is the 480V a wye (3 phase + neutral)? If so, you don't need a transformer for the 277.

Your missing the point. if the service is 480 3 phase then you need a transformer for the 120 loads. depending on the load on the transformer the lighting might push it up one size.

other than losses through the transformer to step down the voltage to 120 I am not aware of any real difference.

With out a intimate knowledge of the installation and rate structure and a couple of hundred other things I know of no good way to make a recommendation.

Fixtures will cost the same no matter what voltage you buy.

The main advantage of 277V. lighting circuits (assuming 277V is readily available) is that you have less voltage drop, the means to do longer runs (from panelboard to fixture), and more fixtures can be attached per circuit breaker (vs. 120V lighting circuits). In the long run, if done properly, this leads to economies of scale and allows for a cheaper, more economical, and efficient installation.

The 277V. circuits use less current (for equal amounts of light on the equivalent 120V circuits) and you may be able to get away with installing a smaller lighting panelboard than otherwise might be necessary.

Beachcomber

277 volts is better as long as you have qualified people servicing the installation. If you are going to use general maintenance persons to do any electrical work, 120 volts is much safer.

The installed cost of 277 volt systems are lower. (Assuming you have a

480/277 volt 4 wire system.)

I would say that 277 save you probable 1% on the transformer loss.... and the wire loss.....

If you are designing something new, and it's a small establishment, do you need 277/480V service at all? Such service is normally necessary only for large loads.

If, for whatever reason, you get 277/480V service, you'll need a 480V/120V transformer for outlets and most small loads anyway. Using 277V lighting rather than 120V lighting means you don't run as much through the transformer, so it acts less as a space heater, and you may be able to specify a smaller transformer than you otherwise could. 277V lighting will lose less power through resistance losses in the wiring as well. Compare the fixture prices as well.

| The main advantage of 277V. lighting circuits (assuming 277V is | readily available) is that you have less voltage drop, the means to do | longer runs (from panelboard to fixture), and more fixtures can be | attached per circuit breaker (vs. 120V lighting circuits). In the | long run, if done properly, this leads to economies of scale and | allows for a cheaper, more economical, and efficient installation. | | The 277V. circuits use less current (for equal amounts of light on | the equivalent 120V circuits) and you may be able to get away with | installing a smaller lighting panelboard than otherwise might be | necessary.

To clarify, you could have more lights on the same circuit, reducing the number of circuits and thus the number of slots in the panel. The higher voltage panels are slightly larger for the same number of circuits when compared to the 3/4 inch Square-D QO/NQOD and Cutler-Hammer CH series if you went with 208/120 for everything. For 480/277 you would use panels like Square-D NF or Cutler-Hammer PRL2.

| 277 volts is better as long as you have qualified people servicing the | installation. If you are going to use general maintenance persons to | do any electrical work, 120 volts is much safer.

He shouldn't be having general maintenance people doing any electrical work in a commercial/industrial setting unless they are licensed as electricians by the appropriate authority, in which case they should be able to handle anything up to 600 volts.

Or are you referring to general maintenance persons doing things like changing light tubes?

But I'd definitely say go with 277 volts for all the fluorescent and HID lighting unless putting them on 120 volts would be less than maybe 60 amps. Shouldn't need any other kind of general lighting in most cases.