Very warm, almost hot wires

[exploziv]

Get some WAGO wire clips (221 series), take a very good look for polarity then proceed on replacing that connector (by exposing new wire, do not reuse last few cm near the burn). You can also buy a fully insulated electric box and wire nuts for it to make it fully waterproof (by putting the wago clips inside the box). If you don't need fully waterproof just take a cable tie and secure the 2 wires together near the wagos so no mechanical force can go to the wago clips. You can then wrap the assembly in electrical tape if it needs to be able to take the ocassional water spray/splash, or if you want to be able to touch it without any worries while powered up.

 

[Ca++]

I can see the brown is nearest, and that's perhaps blue at the back (or was before it burnt). What is the green stuff over each?

 

[exploziv]

Could it be copper corrosion? Or part of the connector melted?

 

[Ca++]

I have noticed more and more Chinese copper/brass, is actually plated steel. The kind of plate thickness, that the screw terminal could remove. A then steel contact has a terrible ccc.

I'm probably reading ahead a bit too much.

 

[exploziv]

Because I am a curious guy myself, and also having a light with this connector nearby, I went to see how it looks inside.
Seing the screw has kind of a cutting edge, I thought maybe they overtighten it and it will cut the wire. I did overtightened it to the max, no cutting happened. It would probably cut the individual strands of copper if they weren't tin dipped before.
The contact part of the connector seems to be brass or similar alloy, I have scratched it with all my force and I couldn't see any diferent metal in there.
Only theory I can throw out there is that they fail from being under tightened, and maybe arcing melts the tin a bit and the problem only gets worse from there. Mine were a bit less tightened that they should have been for my liking, but not enaugh that it could cause problems. And this is a light I used before with no problems.
I will soon check my bigger light to see how that looks in there, will report if I find anything new/diferent.
Oh, and there should't be any green stuff in there, unless they fogot to tin dip, or it melted away and exposed the copper.

 

[Absorber]

The saga continues. Mars did step up and send a new oversized connector. Started a grow and connector was normal temp and I stopped checking it until a few weeks before harvest. The temp was very hot. I could barely touch it. I don’t know what’s up with this light but something clearly is. I opened it up now and All wires were secured. Screws were tight. But it’s lucky I didn’t catch fire. The little remaining plastic wire coating was melted and brittle. I feel very lucky. Now wtf to do with this turd of a light.

If your wires were tarnished from heat before you replaced the plug ,replacing the plug is a short term fix as the cable has lost some of its current carrying capacity once it's burnt .
And if you are seeing green on the wires it can happen when copper wires sweat though I've generally only seen it in old household wiring that's been overloaded and running for 40+ years .

 

[blondie]

As for the screws being under tightened, not possible in this case. I’m going to get a wago connector and see if that works or maybe better time to upgrade.

 

[exploziv]

If you used the burned wires doen't even matter how well you tightened it. Actually, with untinned copper, they should not be overtightened cause you can risk severing some of the strands. Thats why I recomended the wago solution, it's easy to use and it regulates the force itself (they made for 0.4 mm2 to 4 mm2 wires), and they clip all of those perfectly with just a flip of the lever. And they work with bare wire, stranded or solid type.
That being said, you need 2 wago connectors, one for each side. All the holes on one are connected together.
Don't know if they have ones with 2 holes, or at least they aren't very usual to find, but the ones with 3 holes should be easy to find. You can leave one unconnected with no problems. They are rated for tens of amps and once clipped on fresh exposed wire if you pull on it and it doesn't come out that means it's properly connected.