Emergency Lighting Issues

[dpm457]

Recently my company hired contractors for a large-scale LED retrofit project (6000+ lamps). They are all 3 lamp T8 2x4 fixtures. The "plan" for the EM fixtures was to wire line voltage (277v) to the two outside tombstones for the LED lamps and then use a normal and EM ballast with a Fluorescent T8 lamp on the center pair of tombstones. This probably isn't the best method but my company wanted to save cash. Now- after 4 months of performing my OSHA required monthly 30 second test, all of the fixtures passed the test. Keep in mind that I was only using the test button for these inspections. During a scheduled building shut-down I decided to conduct the annual 90 minute inspection and a vast majority of the EM fixtures did not even attempt to turn on- just dark. Because it wasn't a 100% fail rate, I know this set-up works. However, I cannot determine the difference in the wiring between the working fixtures and the failed ones. So my question is: Why would the EM ballast and lamp operate while using the test button but not on a total loss of power?

Signed,
So Confused!

 

[ron]

First would be to see what the test button does. Does it cut line voltage to the EM ballast or does it just start a test sequence not actually draining the battery?

 

[GoldDigger]

Measure the voltage on the input wires of the EM ballast. Possibly there is stray voltage which will not fire the lamps (and so appears to be an open circuit) but is keeping the voltage loss from being detected. But with the whole building shut down at the main I am not sure where the stray voltage would come from. What happens when you only turn off only the lighting breakers?

 

[dpm457]

Measure the voltage on the input wires of the EM ballast. Possibly there is stray voltage which will not fire the lamps (and so appears to be an open circuit) but is keeping the voltage loss from being detected. But with the whole building shut down at the main I am not sure where the stray voltage would come from. What happens when you only turn off only the lighting breakers?

I am not in a position to open breakers during business hours, but I have been using the quick disconnects to simulate power loss.

 

[dpm457]

First would be to see what the test button does. Does it cut line voltage to the EM ballast or does it just start a test sequence not actually draining the battery?

Thanks Ron. How can I determine what the button does? Check spec sheets or is there a test?

 

[GoldDigger]

I am not in a position to open breakers during business hours, but I have been using the quick disconnects to simulate power loss.

If the disconnect "works" that still leaves the possibility of stray voltages on the branch wiring. One step at at time sounds good.

 

[JFletcher]

I would take a second look at the wiring between a fixture that doesnt work on power failure/quick disco and one that does. Take pics.

 

[ron]

Thanks Ron. How can I determine what the button does? Check spec sheets or is there a test?

Since the existing fixture was custom wired with the new EM ballast, the wiring was hand made and needs to be inspected on a fixture by fixture basis.

Go to the website for the EM ballast manufacturer and get a wiring diagram (sometimes it is printed on the ballast itself) as see it it is wired as a charging power cutout.