T8 LEDs started working intermittantly after three months of working reliably

Question

About three months ago I replaced a single 4 bulb florescent light fixture with four Sylvania Type B T8 LEDs. I bypassed the two ballasts involved so they cannot be part of the problem. The lights have worked flawlessly since then, but yesterday all four bulbs stopped working simultaneously (After flipping the switch to turn them on they flickered for less than a second and then would not turn on). This morning (about 10 hours later), I tried turning them on again, and they worked -- for about two hours (and through a dozen or so on/off cycles), but now they won't turn on again. The fixture is mounted in our bedroom walk-in closest, on a 12' ceiling that's a pain to work on. We probably turn these lights on half a dozen times a day on average.

I thought LED bulbs would be much less of a hassle than florescent, but I only had to replace/service the fluorescent bulbs three times in 20 years. I figured LEDs would last for a decade at least, but these LEDs only lasted three months. What gives!?!

Just wondering if anyone had any idea what might be going on. I have no reason to believe the wall switch has any problem, but I have encountered individual LED incandescent-style bulbs that occasionally stop working for a while and then suddenly work again. Is this a normal feature of LEDs? That they just randomly stop working for hours?

Answer 1

Since they are direct-wire/ballast-bypass, the four "tubes" are completely independent individual entities. Imagine if you bought four toasters, put them in your kitchen and one toaster stopped working. Well it's that toaster obviously. But if all 4 stopped working? 4 simultaneous failures? I don't think so. Clearly, not the toasters.

So, go back and check your wire nut connections on all those splices, including back at the switch, and including the neutral. Remove any tape, hold the nut and pull firmly on each wire one at a time. (scale it down a bit for 18 AWG wires, they're not that strong).

If any wires pull out, it had a poor physical connection. That also means a poor electrical connection which causes the above, but also, arcs and starts fires. Tape is bad news in wire nut connections. It usually means the installer has not developed good technique (typically: not tightening nearly enough), and is using tape as a crutch. This breeds arc faults.

If there are "back stab" connections on the switch or at prior points in the circuit, those can fail just like this also. They usually "fail safe" but I wouldn't count on it. I have no idea how backstabs got UL approved.

Answer 2

I would be looking for a bad connection, unfortunately it will probably be in the small ~18 awg wire going from hot or neutral up in the fixture since that was what was changed and there is no mention of prior problems.

Why will it work intermittently? This is one of the tell tails of bad connections

The advantage to direct wire LED’s in this case is 1 lamp may fail and the other 3 will continue to function.

to say something is ok based on age a voltage spike could damage them however since you have 4 direct wire lamps it would be rare for them all to fail at the same time.

I would be looking for a bad connection, unfortunately it will probably be in the small ~18 awg wire going from hot or neutral up in the fixture since that was what was changed and there is no mention of prior problems.

Why will it work intermittently? This is one of the tell tails of bad connections

The advantage to direct wire in this case is 1 lamp may fail and the other 3 will continue to function. But if the main hot or main neutral connection fails all 4 lamps will fail.

This is one place I recommend wego lever locks first because in my experience most linear lighting fixtures (the 4’ style) will be modified 2-3 times over the life of the fixture or that has been my experience in the past. Lever locks work with fine gauge wires and larger fixture wires because each wire has its own clamp.

The LED’s should outlast the fluorescent in many cases provide more visible light at 1/2 the wattage.

Don’t give up on the LED’s I doubt they are the problem most likely a bad connection.