Strange behavior on newly installed T8 fixtures

[StephenFreskos]

I'm new to the forum but have been using it for work related technical troubleshooting for quite some time now. I'm actively involved in energy efficient lighting retrofit design and construction and have managed millions of dollars worth of lighting upgrades. Not bragging, just a little background.

New fixtures: 1st Source T8 High Bays 4' - 4 lamp fixtures, with GE 74476 ballasts model #: GE432-MVPS-H, ballast factor 1.16, Program / Rapid Start, parallel wired, running on 120V. These ballasts have the Multi-Volt Technology auto-sense circuitry. I've used around 5,000 of these ballasts now.

Problem: Lights in certain fixtures in this room will completely shut off, then turn back on about 1 second later. It's fast enough that it's hard to catch if you're not staring at the ceiling. At first, it seemed to be happening to only 3 lights, all on the same circuit. Then I saw it happen to another couple lights on other circuits.

Background:
We upgraded 15, 300W incandescent light fixtures in this room. This building was built in 1949. The room I'm having a problem with was adjacent to part of the building that burnt down sometime in the '80s, although the room suffered no visible damage.
At some unknown point, new TWN was installed on the lighting circuits. No ground wire in the conduit.
We've installed the same ballast and fixtures in 4 other rooms in this building with no problems.
This room has a 6 pole relay, controlling the 6 lighting circuits in this room from a wall switch. Relay is 1959 vintage and mounted directly to the bus in a 1959 Westinghouse panel.

Since all we did was connect new light fixtures to the existing wiring, and my sub has rechecked his splices, I'm pretty sure it's due to an existing problem with the building wiring. We've checked all connections to the breakers and to the relay with no issues found. What's weird is that only one fixture will do it at a time. Not all 3 fixtures on the circuit blink out. So it couldn't be a corroded contact on the relay could it?
We haven't yet pulled the relay to examine the contacts.

Any ideas?
Anyone had problems with the Multi-Voltage 120-277 ballasts blinking out like this?

I'm starting to think there's voltage fluctuation on the line that puts the ballast into auto-sense mode for a second, causing the lights to blink off then back on...

Thanks.

 

[Dennis Alwon]

Well the first thing I would do is see if all the lights that are having this issue are on the same phase. If that is the case then change phases and see what gives.

Then I would hook one of the problem lights up directly to a panel--If the problem continues that it is likely this may be a manufacturing issue.

You can also take a fixture from the room that is not having the problem and install in the problem area and see what happens.

 

[ceb58]

If you can identify the ones doing it you may need to check the grounding. Have heard/read that some will not operate properly with out a ground. It could be a case of the ground being loose some where.

 

[StephenFreskos]

Dennis: Ok. Great suggestions. I'll be making this happen in the next week or so.

Ceb58: I suppose it could be an intermittent grounding problem. This makes sense. Unless the conduit has come partially apart or has corroded, then I wouldn't expect this to be the issue, but since there is no ground wire in the conduit, it is a possibility.

One issue here, is that the fixtures are very high off the floor and require lifts to remove and replace fixtures. Yuk.

Thanks
-Stephen

 

[sparkybac]

Have you considered contacting the ballast manufacturer and running the problem by them? They are usually pretty helpful.

 

[BullsnPyrs]

We have had a similar problem with T5 multi volt ballasts. The problem then was with the neutrals being overloaded and servicing multiple circuits on the same phase. What are your voltage readings at the fixtures? Hot to Ground, Hot to Neutral and Neutral to Ground?

 

[hurk27]

I had this problem in a retrofit job where we had a bad neutral on a multiwire circuit, as the voltage to neutral would fluctuate it would keep changing voltage in the ballast and for a split second the lamps would turn off?

 

[StephenFreskos]

Folks:
Much thanks. We haven't yet embarked into the fix for this problem. I had my electrician check his splices, check all the hot and neutral connections at the panel and check the relay connections. We checked voltage but didn't check hot to neutral and neutral to ground. The neutral IS serving multiple circuits.
Sounds like round two of analysis is in order. We were set to pull new conductors, this time including a ground, but the problem with this approach is that there isn't a good ground at the panel. We have to look further down the path for a good ground.
Cheers,
-Stephen
Construction Manager, Energy
AECOM

 

[ceb58]

Folks:
Much thanks. We haven't yet embarked into the fix for this problem. I had my electrician check his splices, check all the hot and neutral connections at the panel and check the relay connections. We checked voltage but didn't check hot to neutral and neutral to ground. The neutral IS serving multiple circuits.
Sounds like round two of analysis is in order. We were set to pull new conductors, this time including a ground, but the problem with this approach is that there isn't a good ground at the panel. We have to look further down the path for a good ground.
Cheers,
-Stephen
Construction Manager, Energy
AECOM

And what is the problem with the ground at the panel?

 

[broadgage]

I would suspect either bad ballasts, 5,000 good ones does not prove that number 5,001 will be good !
OR a bad neutral if this is a MWBC, a bad neutral will result in low voltage on one phase, perhaps low enough to cause the lamps to go out. The voltage would be high on another phase but the multi-voltage ballasts are probably fine with that so it has not been noticed.

I doubt that a poor or loose ground at the fitting is the problem, some flourescents need a ground to strike reliably, but absence of the ground wont make a lit lamp go out.

 

[jmellc]

Neutral or ground sounds like a culprit to me too, how easy would it be to run new conductors? How is your ground bad at the panel?

How about the contactor? Didn't you say it's a 1959 model? It may be on its last leg. Have someone stand by it & see if the coils lose their hold for a split second. Just a thought.

 

[Electric-Light]

You may have a power drop somewhere causing the ballast to reboot.

Incandescent, magnetic, and instant start will appear to "flicker" but programmed rapid start is designed to go through a pre-heat sequence at start, so instead of "flickering" it goes through a full starting sequence which explains ~1 second of outage.

 

[Electric-Light]

Since its past 15 minutes and I can't edit....

Since its past 15 minutes and I can't edit....

If it's long enough, it will reboot. Rebooting is something unique to programmed rapid start. T5 systems are also PRS, because the cathodes to fit inside the small tube can't be made as large and durable as what fits inside a T8 bulb. Krypton buffered fill gas as well as the narrower tube diameter raises starting voltage needed to start brute force (like T8 instant start).

No excuse for the underlying cause, but why did you spec out PRS? They're usually used for frequently switched applications like occupancy sensor, classrooms or single-user restrooms.

Incandescent, magnetic, and instant start will appear to "flicker" but programmed rapid start is designed to go through a pre-heat sequence at start, so instead of "flickering" it goes through a full starting sequence which explains ~1 second of outage.

Can you attach a Fluke 189 or 289 and monitor the events over time?