277 volt ballast using 240 volts?

Unicks

Active Member
I recently stumbled upon the opportunity to pick up a bunch of 250 watt HPS industrial fixtures and bulbs for free. The only problem is they are rated at 277 volts. I cracked open the enclosure to see if the ballasts were multi-tap, but as far as I can tell they aren't.

Now my question: I happen to have a 240 volt source in my grow closet, so as an experiment I wired up one of the fixtures. They ignite just fine and burn indefinitely. Are there any adverse affects of running the fixture at a lower voltage than intended? Is there a significant reduction in light output?

Any help would be appreciated. Thanks.
 

mockingbird131313

Well-Known Member
Bump. Anyone with experience, or perhaps an electrician?
I chase sparks for a living. This will not work. Sometimes lights have a 120/277 tap arrangement. But, from what you said, you have a single phase of a three phase network to feed the lights. Residential wiring is two out of phase wires to create 240 volts.

There are different power converters used to make 240 residential into single phase 277 so people can operate and industrial drill press or small metel lath in your basement workshop. So you could go to an industrial machine supple company and find a solution to your problem.

But I would suggest you keep the lights and housing. Consider buying a new, replacement ballast that is rated at 120v or 120/277V. Before you install this in your house, wire it, set in in your driveway, and burn it for a half hour, to insure you do not over heat and start a fire.
 

Unicks

Active Member
I chase sparks for a living. This will not work. Sometimes lights have a 120/277 tap arrangement. But, from what you said, you have a single phase of a three phase network to feed the lights. Residential wiring is two out of phase wires to create 240 volts.

There are different power converters used to make 240 residential into single phase 277 so people can operate and industrial drill press or small metel lath in your basement workshop. So you could go to an industrial machine supple company and find a solution to your problem.

But I would suggest you keep the lights and housing. Consider buying a new, replacement ballast that is rated at 120v or 120/277V. Before you install this in your house, wire it, set in in your driveway, and burn it for a half hour, to insure you do not over heat and start a fire.
Thanks for the information. Can you point me to a site, or give me the name of a company that sells these 240 to 277 volt converters? I've done some searching on google but haven't come up with much. Thanks.
 

mockingbird131313

Well-Known Member
Thanks for the information. Can you point me to a site, or give me the name of a company that sells these 240 to 277 volt converters? I've done some searching on google but haven't come up with much. Thanks.
Ah yes. hdsupply.com and the Granger / Lowes site both have thick sections of lights and supplies. The key here is to dismantel your present fixture and take out the ballast. Find a replacement ballast with the same or smaller footprint.

Be careful and look for any capacitors. Even a small one will dischage you into next week, if you bump it.
 
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