Shop light wiring

[StevenW]

I have ordered T5 light fixtures for my metal building which have universal voltage ballasts that will accept 110 to 277 volts. The guy I ordered the fixtures from said the lights would use less current if wired for 220V. Can someone explain this?

[HayZee518]

as the supply voltage goes up, the amperage draw reduces by one half. efficiency operating at a higher voltage goes up. so if you wired it for 120 volts at say 8 amps, wiring it at 277 the amps would be 4 amps. wire size would drop to #14

[StevenW]

I already have the circuit wired as 110V, 20A with 12/2 WG. Would I have to change the wiring at the switch to make it 220V? I know I would have to either add a second 20A single pole breaker or replace with a double pole breaker.

[HayZee518]

no, the circuit will draw one half what it would at 120 volts. do you have a three phase service? that would be the only reason to have 277 volts for lighting. if you don't then stick with the 120 volt

[HayZee518]

other than efficiency there would be no other reason to use the 277 tap on the ballast. a three phase service 120/208-277 would be needed for 277. voltage of 220-240 wouldn't save you anything. you'd actually measure 277 volts to the neutral with a meter.

[StevenW]

I don't have a 3-phase service. I'm looking for max efficiency and if using 220V would be any more efficient than 110V I would do it.

[StevenW]

I was thinking the electronic ballast would auto-detect the incoming voltage and operate at anything between 110 and 277V.

[HayZee518]

if that's the case try it! the wiring would be off a two pole breaker.

[StevenW]

Would the light switch wiring be the same as 110V, just make the neutral a hot?

[HayZee518]

switch wiring would be the same as a 120 circuit. BUT you've opened up a new "ball of wax." the switch has to be 277 volt rated for a tungsten load.

[StevenW]

Well my light fixtures were finally delivered and I hung and wired them yesterday. Initially they were on 120V, but today I added another breaker and moved the neutral and marked it appropriately. Now the lights are running on 240V. Yes, the electronic ballast auto-detected the input voltage and my light switches were HD switches from Lowes that are good to 277V.

If nothing else, it's different. Thanks HayZee518!


I was going to post pictures but..."You are only allowed to post URLs to other sites after you have made 15 posts or more."

[StevenW]

Here you go...

[mrcaptainbob]

Ligthting...

Nice job! I learned something, too. Did not know new lights could be driven from either voltage and self accomodate...thanks!

[StevenW]

Well it would depend on the ballast. Here is the spec sheet for the ballast used in my lights...http://www.ace-ballast.com/articles/...-A2_54T5XS.pdf

[HayZee518]

Look it all the "fun" toys!