Inrush or Surge? How to Protect Against Either?

Brentgi

Active Member
Good afternoon everyone!

I have a small issue that I am facing and am hoping that I can get some more definitive insight on the problem that I'm having.

I've got a handful of Chroma-Q inspire fixtures that are used as house lighting. Overall, I love the fixtures and have been very pleased with them.

However, in the year and a half that they've been installed, I've had two fixtures go dead on me. The first on was under warranty and was repaired at no cost by the manufacturer. The second one, however, is outside of the warranty period and we have to pay for repairs to the fixture. If this continues to happen at this pace, the cost of repairs will negate one of the reasons why we went to LED fixtures in the first place.

I thought the first failure was a fluke and was glad that it was still under warranty. The second failure, however, has me asking a few more question. I will explain below and I'll appreciate any feedback that you might have for me.

Both fixtures failed during either power-off or power-on. It's hard to tell. The first fixture went bad during a crazy storm last year and power to the building was interrupted. When power was restored, the fixture was dead. The second fixture died during a circuit reset (we have work lights that are connected to breakers in the same panel, and it seems that someone might have switched off the breaker for house lights when they switched off the work lights). When power was restored to the house lights, the 2nd fixture was dead.

My first thought was inrush... But after doing some research and reading pages and pages of forum posts, I think that this is less likely the culprit (inrush will just trip the breaker, right?).

My second thought was surge... What's the likely hood of experiencing power surge during a circuit reset? Would this cause a random fixture to die?

Here's how they are powered:
-3 fixtures each on a 20amp circuit breaker.
-No surge suppression or any dry contacts between the breaker and the fixture

Any practical suggestions on how to prevent this is the future?

Thanks!
Brent

EDIT
Todays Lesson: Never jump to conclusions without getting on the lift for yourself to check things out. I had reset the circuit TWICE and the fixture still did not come on. When I got to the fixture, I simply unplugged it and plugged it back in. AND NOW IT WORKS! WHY?????? Total head-scratcher here...
 
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Wild guess but I would say the Caps were discharged and for some reason and not supplying the fixtures PSU with enough juice to turn the fixture on.

With smarter tech this shouldn't be an issue and would leave me to believe the PSU is on its last leg. If you are handy enough you can swap out the PSU since the fixture is out of warranty.
 
Todays Lesson: Never jump to conclusions without getting on the lift for yourself to check things out. I had reset the circuit TWICE and the fixture still did not come on. When I got to the fixture, I simply unplugged it and plugged it back in. AND NOW IT WORKS! WHY?????? Total head-scratcher here...

Yup. Sounds about right. Occam's razor is a cruel mistress. Was it the PowerCon connector that you reseated or a connector that plugs into the wall? If the PowerCon is suspect, I would pull the cable connector end apart and check the internal terminations. Make sure the crimps or screws are ratcheted down and everything looks kosher. If there's no hint of a problem with the cable itself, possible where it plugs into the wall is a bad receptacle that's had the contacts on it roached and isn't making good contact. Or if there's any 2P&G involved it may be time to spread some pins.
 
Wild guess but I would say the Caps were discharged and for some reason and not supplying the fixtures PSU with enough juice to turn the fixture on.

With smarter tech this shouldn't be an issue and would leave me to believe the PSU is on its last leg. If you are handy enough you can swap out the PSU since the fixture is out of warranty.

Even after only 1.5 years of use? Interesting. I guess it's probably over 10k hours of use on the PSU, since they are always on (the fixture, not the LEDs). Still seems like a relatively short lifespan.

Yup. Sounds about right. Occam's razor is a cruel mistress. Was it the PowerCon connector that you reseated or a connector that plugs into the wall? If the PowerCon is suspect, I would pull the cable connector end apart and check the internal terminations. Make sure the crimps or screws are ratcheted down and everything looks kosher. If there's no hint of a problem with the cable itself, possible where it plugs into the wall is a bad receptacle that's had the contacts on it roached and isn't making good contact. Or if there's any 2P&G involved it may be time to spread some pins.

I reseated the connector that plugs into the ceiling. It's a twist-lock connector. Never considered checking the outlet. I'll have to give it a look next time I'm up there as well as checking the plug itself.
 
Not outside of the realm of possibility the twist-lock connector wasn't fully seated when it was plugged in and the most recent gust of wind, seismic event, or vibration from thunder, nearby mechanical equipment, or construction next door was just enough to wiggle the connector to lose contact.

If you still have the lift in place you could inspect the contacts and make sure there's no sign of arcing or scorching on the pins that you might see from a loose connection and exercise the twist-lock a couple times to see if it's locking as well you think it should be. Beyond that, I wouldn't look any further unless it happens again. Almost certainly unrelated from the circuit breaker getting flipped.
 
Like I said wild guess. Power outages do some pretty weird stuff.

I lost my whole led rig one day cause of a power outage. It reset one of the fixtures into slave mode and pissed the rest of everything off to the point where I had to kill power cause they would just randomly turn on. Sure as shooting it was the second to last damn fixture that I checked before finding that out.

Power outage has also eaten two of my PSUs in two different fixtures. So it's not unheard of for something like that to happen.

However Mike is prolly right. Check the outlet and check the plug inside and out.
 
Power interruption can also lock up the microprocessor in the thing. Usually, this will happen if the power is off for a very short period of time. Too short a time and the caps in the unit will not fully discharge resulting in the microprocessor NOT doing a reset, but stuck with bad data from the power drop off. Unplugging the unit then plugging it back in will reset the processor, thus fixing the problem.
 
My first thought was inrush... But after doing some research and reading pages and pages of forum posts, I think that this is less likely the culprit (inrush will just trip the breaker, right?).

Correct. Inrush is the effect the fixture has on the electrical system. I seem to remember a retailer touting "inrush protection" for his gear and was quickly corrected. Inrush is a "pull", not a "push".
 
To expand on the connector aspect of the troubleshooting. I would also check the internal wire clamp screws to make sure that they are still tight. The copper strands tend to compress over time so it is conceivable that the screws could now be loose. I would check that on both ends of the cable.
 
Regarding the subject line of the original post, it would be convenient to have a power strip with a built-in inrush current limiter. Does that exist? I can only find the raw electrical components online.

It can't be done. An inrush limiter has to be designed specifically for the load applied to it.

If this really becomes a problem, then manufacturers need to solve it by designing products that don't have stupid amounts of inrush. The proper place to address this is with good power supply design.
 
Regarding the subject line of the original post, it would be convenient to have a power strip with a built-in inrush current limiter. Does that exist? I can only find the raw electrical components online.
Here you go: http://www.mouser.com/ds/2/168/920-325D-LR-245176.pdf
So, they predate WWII and have been in use for many, many years. So, there are two very important things to understand about them:
1) They operate VERY VERY HOT. Did I say they were Hot? As in, they really have to be isolated from anything that might melt or burn. They are made to be hot. When cool, they have a high resistance, as they heat up, the resistance plummets.
2) They have to be matched (with some latitude) to the load.
 

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