PSA - keep your power cords raised, not touching your Kingbright

N

nygaff1

Well-Known Member
As the title suggests, keep the cable raised. The heat sink melted right intothe sheething. Who knows how much longer I had before it melted through and shorted the circuit. This didn't even occur to me as a possibility - and I have been in entertainment lighting for 20 years...

Thank god I went into the tent to shift some things around and found this. It was the new 240w 2022 LMB201 diode fixture. My slightly older 480w with a smooth sync is cool to the touch in comparison.

They sent me a new cable, which will absolutely be installed with a cable tie and nothing resting on the fixture. Im just super grateful I learned this lesson the easy way.
 

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A light shouldn't get anywhere near hot enough at that wattage to melt rubber.

I've got a 240w QB and it rarely gets over 50c-60c on the hottest point. Which is well over 100 degrees Celcius less than the melting point of the material used.

The rubber used in these cable sheaths has a melting point of around 170-190c.

That is insane to see. Would not expect that at all.
 
VincenzioVonHook said:
A light shouldn't get anywhere near hot enough at that wattage to melt rubber.

I've got a 240w QB and it rarely gets over 50c-60c on the hottest point. Which is well over 100 degrees Celcius less than the melting point of the material used.

The rubber used in these cable sheaths has a melting point of around 170-190c.

That is insane to see. Would not expect that at all.
Click to expand...
Yeah, that was my thought too... it wasn't even st full, dimmed to ~60%

My IR temp gun read 119f on this one, but that doesn't explain the temp jump to melt the butyl rubber. Odd indeed.
 
Rurumo said:
This is good advice for any light, there is just no reason not to lift them up off the fixture, just takes a few seconds.
Click to expand...

Exactly what I was going to say.

Keep any and all cords and cables away from your lighting, it's heat sinks & driver/transformer units. Not just the power cables, but also any ratchet straps or anything.

4809110_grow-journal-by-leastexpectedgrower.jpg

Here's from when I was setting up my HLG 225's a while back. Note that even the loose hanging ratchet lines all get secured up at the ceiling of the tent.
 
nygaff1 said:
Yeah, that was my thought too... it wasn't even st full, dimmed to ~60%

My IR temp gun read 119f on this one, but that doesn't explain the temp jump to melt the butyl rubber. Odd indeed.
Click to expand...

I wouldn't place any bets on some companies cutting corners on materials...but I'd also say that if your cable is in contact with the heat sink, then it's not cooling as it should, and you're creating a hot spot on your sink and all bets are off.

Edited to add that in any case, most of us use our lights unattended (I mean,I don't know anyone who sits in their grow room/tent 18 hours a day or even 12 hours a day) and it's such a simple thing to keep your lighting hardware clear so you don't have to worry about it. Even when I've left for a few days up to nearly two weeks I do a visual check to make sure that my lights are clear, all other electrical is raised and that if there is a water run away situation it's not going to cause problems.
 
VincenzioVonHook said:
A light shouldn't get anywhere near hot enough at that wattage to melt rubber.

I've got a 240w QB and it rarely gets over 50c-60c on the hottest point. Which is well over 100 degrees Celcius less than the melting point of the material used.

The rubber used in these cable sheaths has a melting point of around 170-190c.

That is insane to see. Would not expect that at all.
Click to expand...
HLG?

I have the 240 watt HLG and noticed same. I have the cords on the heat sink but as others have pointed out it's a good idea to lift them regardless.
 
GrodanLightfoot said:
Um..

I tested this theory long ago because I was afraid the nylon ropes would melt at 100%. Total BS

View attachment 5169871

But youuuuu just made me climb a ladder and check anyway. Troll succeeded. No fucking melted plastic,of course not. Got me!
Click to expand...

Depends on the light design & wattage entirely. The 225's I use are basically overclocked QB96's running at 225W. The sinks on them heat to an excess of 200F degrees. If they were running at 100w it would be a different story.
 
Rufus T. Firefly said:
HLG?

I have the 240 watt HLG and noticed same. I have the cords on the heat sink but as others have pointed out it's a good idea to lift them regardless.
Click to expand...

Yeah, the HLG are literally made in the same factories. This was a Kingbright branded unit. I'm guessing I got the 240w unit comparable to HLG's new black fixtures.

it's much hotter than the domestically assembled 480w fixture with a smooth heat sync that i got on ebay.
 
GrodanLightfoot said:
Um..

I tested this theory long ago because I was afraid the nylon ropes would melt at 100%. Total BS

View attachment 5169871

But youuuuu just made me climb a ladder and check anyway. Troll succeeded. No fucking melted plastic,of course not. Got me!
Click to expand...
Lol. Better safe than sorry for sure. But I do have to say the horizontal aluminum bars on your light^ probably help dissipate more of the heat. Also your driver isn't attached to the heat sync like mine is.
 
ComfortCreator said:
Every comment here is good imo, rare :)

My 2c is it's always good practice, if you run any lights that you arent comfortable holding your hand on the heatsink, run a fan over the heatsink.
Click to expand...
I know right? Refreshing indeed :D

Just to clarify, this was a new addition to the tent. I checked it about a week later. Should have daily, but that's my mistake. Also, there was a clipon pointed towards the top of the ballast. I can't imagine how hot that actually got :(
 
That's crazy that it would get that hot. People are always saying HID lighting is a fire hazard but I can set anything on top of my hood and there's absolutely no chance it will melt.

Good catch though. It could have eventually caused a serious problem.
 
nygaff1 said:
Yeah, the HLG are literally made in the same factories. This was a Kingbright branded unit. I'm guessing I got the 240w unit comparable to HLG's new black fixtures.

it's much hotter than the domestically assembled 480w fixture with a smooth heat sync that i got on ebay.
Click to expand...
No they are not made in the same factories.

You've got something wrong . Only time I've seen this I when the pcb has the copper exposed by a pan head screw that's got a sharp edge and causes a short circuit making the heat sink incredibly hot very quickly.
Either that or kingbrite have sourced some dodgy cable, which I doubt they would do because they have a solid rep.

I would take the unit out, check the screws holding the boards to heatsink and unscrew to check for copper showing.
If there is any a nylon washer under the screw should fix it.
Another option is a lot of the heat sink is not in proper contact with the board.

Some of my non QB higher powered leds get pretty hot but never that hot unless there's a fault.
 
nygaff1 said:
Yeah, that was my thought too... it wasn't even st full, dimmed to ~60%

My IR temp gun read 119f on this one, but that doesn't explain the temp jump to melt the butyl rubber. Odd indeed.
Click to expand...
The other option is the wire in the cable is broken or connector not fully connected creating arcing which has heated it up and the weight of it sat on the heat sink has melted it into it.
As in , its melting from the inside not out.

I did this once with a 1000w hps many moons ago.
The male was not fully connected to the female, walking in and black smoke coming from cable as both parts were melting
 
coreywebster said:
The other option is the wire in the cable is broken or connector not fully connected creating arcing which has heated it up and the weight of it sat on the heat sink has melted it into it.
As in , its melting from the inside not out.

I did this once with a 1000w hps many moons ago.
The male was not fully connected to the female, walking in and black smoke coming from cable as both parts were melting
Click to expand...
It may not be arching but just a high resistance at the connector. Either way, I agree.

It's always a good idea to feel connectors and cables to check for excessive temps.
 
Last edited:
My heatsink and driver would get pretty warm. But not like that. Also, I did install cpu fans atop the heat sink blowing across it and the driver. 1 fan for each light. Super cheap and worth it to keep operating temps within reason.
 
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