We have a quantity of close to 90 RAAB Led Lights, 260W @277v. A large quantity have been burning out. 20 amp circuit and each circuit is below breaker rating. Speaking with the OEM rep, they say this is the first time hearing about this issue . They said check for surge and common neutrals. We did install a surge protector and during the installation we found that we have common neutrals and that there is up to 24 amps on it. There are 20 circuits involved here and it is a 100% lighting circuit. Nothing else is powered by these circuits. All on, all off. Question is: If it is 100% lighting circuit is the common neutral an issue? If so, how?

 

Welcome to AAC.
Start by breaking each circuit down into individual circuits. Test each individual circuit by itself. Check for voltage. Check for proper neutral and proper ground (if grounded). I've seen 277VAC but have never worked with it so I don't fully understand the circuit. Perhaps you get 277 from two of three phases - I just don't know. But run each circuit by itself and make sure the entire circuit is properly connected.

 

Welcome to AAC.
Start by breaking each circuit down into individual circuits. Test each individual circuit by itself. Check for voltage. Check for proper neutral and proper ground (if grounded). I've seen 277VAC but have never worked with it so I don't fully understand the circuit. Perhaps you get 277 from two of three phases - I just don't know. But run each circuit by itself and make sure the entire circuit is properly connected.

I appreciate the effort!

 

Under normal conditions it is not likely that any branch voltage is higher than the supply voltage. In a split phase system where there are two opposite phase branches and one common neutral, a poor neutral condition can certainly allow different voltages on opposite sides of the neutral.In that sort of instance there is a need to repair the neutral connection at whatever point it is week.

 

To investigate the possibility of voltage peaks you need to monitor AT THE DEVICE connections. Monitoring or measuringat other places may produce inaccurate results.