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Power cable wire thermal capacity

B

BaneSilvermoon

Junior Member
I wasn't sure what thread to put this in.... actually I'm not even sure I should be asking at Anandtech heh, but I thought I'd check in-case anyone around here knows. I'm sure there are some modders around who have some electrician knowledge.

I'm trying to find out what kind of heat ... I guess the "wire insulation," if that's even correct terminology, on a PSU can handle before it starts melting.

Basically, if I were to take one of these wires out of one of those 4 pin molex connectors and sit it against a piece of 150 degree (f.) metal for a couple days, would the wire insulation melt?

I figure this should be easy to find online but I'm having trouble working together all the correct terminology to find what I'm looking for heh.



::edit::
I guess I'm looking for a thermal operating range rating? Fan thermal sensors are pretty much the same type of wiring as far as the insulation right? And they can safely be placed within the fins of a heatsink that may be pulling heat off of a 200F processor.
 
Your question is kind of like asking "What color is a car?" ...depends.
It depends on what whom ever bought the wire spec'd. There is no "standard" heat rating for wire insulation.

If possible (enough room?) you could add sleeving of known thermal properties.

If the CPU is 150°c, the HS will be much cooler.
What, exactly, are you doing?
 
Planning on making a simple support for a heavy heatsink in an upright case. I've been trying to come up with the best way to tie it to a steel support beam in the top of my case and I noticed there is an opening along the 12 heat pipes that runs down through the entire heatsink.

Your typical wire on a 4 pin molex is the exact same size as said opening. Seems to be about 20 gauge. So I was thinking, rather than run a bare steel wire in my case as I had originally planned, which just doesn't seem like a great idea to me. I could get a long insulated wire off an old power supply and use it to tie the heatsink off.

I'm sure those openings are there to aid in airflow around the heat pipes but I wouldn't think blocking one off would effect it to drastically. But doing it that way leaves whatever wire I use pressed directly up a copper heat pipe, almost for the entire length of the heat pipe. So I figured temperature should be a concern.

I wouldn't want melted wire insulation cruising around in there. And for that matter if the insulation melts off then I might as well have just used the bare 20 gauge Galvanized wire in the first place.

Of course I just heard the operating temperature of nylon zip ties goes up to 185 degrees.... so maybe I should just go that route heh. Wouldn't think Nylon would transfer heat into whatever I tied them into either. For that matter they could just be looped into more zip ties.... ghetto looking.. but it works.

Still wire would be preferable if it's feasible.
 
Put a piece of Styrofoam between the wire and the metal. You can carve it out to match perfectly. A heatsink is not going to get hot enough to melt Styrofoam and will insulate the wire from any heat.

Edit:

I just pulled out my Mouser catalog and looking at the different suppliers of wire that could be used in a power supply, the lowest temp on any of it is 80C. So I would just put a tie on it and go with that. If your heatsink reaches 80C you got bigger problems than the wire.
 
Any decent wire should have the temperature rating stamped right on it, but it may be small enough it's hard to read. One PSU I happen to have out has all external wiring rated for 90C = 194F, but the actual melting point is probably higher.
 
I don't think I've ever seen a PS with wire rated less than 80deg C, and that's the safe operating temp, can probably take considerably more before melting, but it's not guaranteed for it's (300v, which isn't even close to being in a PC) rating or longevity over that temp.

If anything in your PC is >80deg you've got bigger problems!
 
+1 for mindless1 - all the PSUs I have the temp and other rating's printed on or embossed into the wire jacket about once a foot. I've not seen PSU wiring without that but I don't get many 3rd or 4th string PSUs through here... I'd think UL has a standard for such things. The printing can be small and/or in a low contrast color that makes it hard to read. Here's a rundown of what I have here: Enhance PSU w/ server-length cable bundles - 90 C; Antec (by Seasonic) EA380 - 80 and 90 C; Zippy HP26550PE (G1) "gaming" version - 90 C on 18ga, 80C on smaller gauge, short ends; Sparkle FSP250 - 80 and 90 C. Nothing in a case should get that warm under normal conditions. I use zip ties when I want to support a heavy heatsink - easy to link if extra length is needed...

.bh.
 
I knew there would be some good answers around here heh. I never bothered to actually look at a PSU since I didn't have one on hand that isn't in use. I was just messing with the cables in a 6 to 4 pin adapter I had sitting around. I should be mounting this thing tomorrow and I think I have decided to just go with zip ties at this point. Simply because the actual act of tying off a cable securely AND to the perfect length, all without applying unnecessary tension is going to be exponentially more difficult than clicking a zip tie a couple notches in until it's snug.
 
::update::

So I couldn't find any zip ties that were long enough while still fitting in between the fins... actually even the tiny ones didn't really fit either..... and I hadn't gotten any CPU cable since I had decided against using it. And of course due to poor planning I had my motherboard out of the case before I realized any of this. So I just went against my own judgement and used the Galvanized steel wire I had originally intended to use. I'm still iffy about having steel wire running through my computer... but the heatsink is in now.

And so far I'm already seeing an 8 degree drop in my cores idle temps. Haven't taken the time to get stress test temps yet.

::edit::
Max temp during a 2 hour OCCT test, small, went from 60C to 42C 😵
 
Originally posted by: Colt45
I don't think I've ever seen a PS with wire rated less than 80deg C, and that's the safe operating temp, can probably take considerably more before melting, but it's not guaranteed for it's (300v, which isn't even close to being in a PC) rating or longevity over that temp.

If anything in your PC is >80deg you've got bigger problems!
Click to expand...

My hd4850 runs at 89C. heatsink runs too hot to touch.
 
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