Question: I'm trying to convert my lantern torchlight into a LED one, using a COB 10 Watts LED.
The LED look something like this, although won't be the exact one.

[![enter image description here](https://i.stack.imgur.com/y1Y4Q.jpg)](https://i.stack.imgur.com/y1Y4Q.jpg)

Is this heatsink suitable for a 10W LED? I found it in my storeroom, most probably scrapped it from my old CPU..

It's 9CM in diameter and around 1.5CM thick. If this can be used, can it be used without a cooling fan? Since the battery will be running on batteries, I'm trying to save as much power as possible.

And do you guys have any suggestions on how to mount the LED onto the heatsink? I'm thinking of drilling two holes then mount it on using bolts and nuts. It'll be great if I can just use thermal glue to glue it on, but I'm not sure whether it'll hold..

[![enter image description here](https://i.stack.imgur.com/93pY8.jpg)](https://i.stack.imgur.com/93pY8.jpg)
[![enter image description here](https://i.stack.imgur.com/pmIBI.jpg)](https://i.stack.imgur.com/pmIBI.jpg)

Answer: 
The usual source is TIA/EIA-568, which also describes the cat5e and cat6
cables used for Ethernet. I believe normal house wiring is cat3 under
that standard.

I'm not sure 'PE' (does that mean polyethylene?) is a specified insulator or sheathing material, though. There are both PVC and other (plenum-rated) sheathing materials for cat5, so the standard is unlikely to be very specific.
PE is resistant to UV, PVC isn't (or rather PE is *more* resistant to UV than PVC). Therefore PE is used outdoors.

PE, though, is more expensive than PVC, so PVC is chosen for indoors.

Yes, you can use PE indoors, but at a cost (so why would you?). You can't, though, (or shouldn't) use PVC outdoors since it degrades over time.