Control/Dimming Circuit popping question

[JaredU123]

So we currently have about 20 1000w scoop lights for our house lights. On one pair (for the most part there is 2 fixtures per circuit) the circuit has been popping the past few days. After some trouble shooting I've discovered the circuit only pops if we use the bump button on our etc expression 3. I Re-recorded the sub with the max levels at 98 and then made it a timed submaster and that seemed to fix the problem. I removed the fader time and tried the bump again and it popped again.

Any idea on why this could be happening?

 

[josh88]

How many amps is the circuit? If it's 20 that's probably the issue. Derating it leaves you right around where you are for your load and the inrush could be what's tripping it.

If my math is right you're have a load of 16.6 amps and derating a 20 amp circuit puts you at 16 amps. Someone correct me if I'm wrong, it's still early.


Via tapatalk

 

[JaredU123]

Our electrical engineer came in yesterday and said the same thing. They are 20amp circuits, however they've been like this for years without issue and we're only having issues with that one circuit.

I figured it was the inrush that was tripping it which is why I set them on timed faders so that if someone happens to push the bump it won't just pop automatically. Seems to be helping. We're having another meeting with the electrical engineer today, and hopefully we'll be switching to dimmable LEDs Soon anyways.

 

[Chris15]

I reckon that particular breaker is going bad.
The inrush on a breaker that's no longer what it once was means it's tripping earlier than it used to...

 

[JaredU123]

Thanks so much for your help! I'll see if we can't replace it. Time to talk to the boss man.

 

[DavidNorth]

What dimmers are you using? Some dimmers have fully rated breakers, can handle 20A continuous current and should not be tripping under cold inrush. Cold filaments, especially tungsten, if these are tungsten, can draw up to 14x their rated current for the first three cycles and not many breakers are designed to properly handle this. This is way different than continuous breaker rating, though.

Did someone recently change a lamp?

David

 

[JD]

Second vote here for a funky breaker. Sounds like you have 9 other circuits set up the same way and only this one is giving you trouble. Sometimes breakers just get that way.

 

[WooferHound]

Look at the bulbs, the filament may be sagging and becoming partially shorted. This should make it noticeably brighter than the others.

It's a Filament of your imagination . . .

 

[porkchop]

Before you start throwing money at the problem I'd do some basic troubleshooting. If possible, swap the dimmer module with another one and try the bump cue on both modules. If that's not possible swap the fixtures and try it that way. This way you're cutting the problem in half. If it follows the dimmer then you can reasonably assume that the problem is the dimmer module, if it follows the fixtures look there, and if it goes away welcome to the wonderful world of trying to fix kinda broken.

 

[BillConnerFASTC]

Why not put an ampmeter on the circuit and see if its drawing more than the rated wattage or more than other circuits? Seems easiest and surest. Also, I'd want to know if something in the circuit was adding resistance, more than just getting rid of problem.

If swapping dimmer modules is easy, that would be a good test, and see if fault moves. Somehow, I imagined some low bid bolt in dimmers which would also make magnetic breakers less likely.