277 volt standards


Old 03-09-19, 10:43 AM
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277 volt standards

Hi guys

Can you give me some feedback?
I installed some 277 volt rated LED lights on a system that measured 281 volts. After about a year, several of the lights failed and kept failing. Then after measuring the voltage over a period of two weeks, it showed spikes of over 300 volts on weekends. So who is at fault here? Should I not have assumed 277 volt rated would be fine? Should 277 rated handle this with some wiggle room? Should the power company be liable?
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Old 03-09-19, 10:56 AM
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277V mains devices must accept +/- 10%. LED's= FAIL.
Old 03-09-19, 11:09 AM
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Welcome to the forums.

Spikes on the 277v line could be from devices in your place shutting off.
Power company is rarely responsible for spikes like that. They maintain +/- 10%.

I had installed a fire alarm in a commercial business that was just refitted. They had installed all 277v recessed LED lighting. There had been a power failure. When power was restored...... half the fixtures were dead. Who's responsible ? They're still fighting it.

I'm leaning towards poorly built/protected LED drivers based on the crap I've seen.
Old 03-10-19, 02:11 PM
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I agree with PJ on this one, the LED drivers I have seen all came from China and I've seen more than a few go bad.

Further, a commercial/industrial facility with a 277/480 volt service could easily have 50, 75 or 100 HP (or larger) motors starting and stopping all of which send surges all over the facility when starting. Utility companies rarely will accept liability for surges, but I have seen them accept liability for a continued over voltage condition. As I recall from almost 40 years ago, I believe the voltage was around 144/288 in a residential neighborhood for a few hours, maybe overnight. Only once do I remember a seriously high surge that blew the bushings off the top of two 34.5 KV oil filled transformers on Easter weekend back in 1987. This is something you never forget, it sounded more like hand grenades going off close by. I was with two others outside the fence at the substation when the second bushing blew. The force sort of picked us up and threw us back about 5 feet. Talk about a "Come to Jesus Moment"! The utility accepted liability by offering to rent to the owner a mobile substation mounted on a flatbed trailer till the owner could get the transformers repaired.
Old 03-10-19, 02:38 PM
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China; at work we are in conversion with a transformer manufacturer who had a 1MV transformer let go. The tap changer caused the explosion. This equipment is large enough to power a mid sized city.

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