Careful when buying eBay PC cables...

[watercooled]

Not sure if this is the best section, feel free to move it if not.

I ordered a 24pin extension cable for a project I'm working on, and it involves stripping one end of the cables, or I probably wouldn't have noticed this.

One is an 18AWG cable on a reel from Farnell, the other is an 18AWG cable from the extension, guess which is which.



The Farnell is the tinned copper (silver conductor) one, if you hadn't guessed.

Yeah, that's just not 18AWG, not even close. Maybe they thought the measurement is supposed to include the insulation? You'd think so, how thick it is relative to the conductor! And all the insulation colours are wrong, they've used yellow, red and black alternately for the whole thing, ignoring what the cable actually carries; it's arguably far less important than the first issue, but it's a pain for me, and why did they even bother using different colours?

Will it matter? Probably not if you're not pulling much power through it, but the wires could potentially generate a fair bit of heat if, for example, your GPU pulls power from the motherboard. Voltage drop could also be an issue.

At least they're copper...

[Biscuit]

Wow that is bad!

A crappy little cable like that is just the kind of thing you think 'il just get it off ebay for a quid'

Lesson learned i guess!

[Agent]

Have you seen the (alleged) Cat5e ones that sell for about £3 for 25 meters? They're just as bad.

[Biscuit]

yeah i picked some up, one of the connectors broke so i went to crimp a new one on it and it was impossible as the cables are so loosely twisted you cant get the individual cores to the same length so they get right into the end of the connector. You always end up with a bad crimp and one of them slips back into the insulation... piss poor.

Lesson i learned - always nick my cable from work

[watercooled]

It's something I may start referring to as the 'cable plague'. Along with Cat5e cables, I also recently bought a microUSB cable as the one supplied with my phone is inconveniently short, but it just kept dropping the connection, popping up all sorts of strange errors at either end. I started a thread about it a while back for advice, as it's really hard to know what's going to be crap, massively overpriced crap, or decent. I ended up getting one from Asda which generally works OK but still occasionally drops the connection.

Hang on to cables you get supplied with decent quality devices!!

[watercooled]

I don't have any callipers to check the actual diameter of the conductor, but I've just compared it against some 7/0.2 (roughly 24AWG) cable, and it's even thinner than that!


Oh and if you're wondering what the background is, it's a place mat. Just the closest dark object to get good contrast with the wires.

[Agent]

I dread to think how much current that could actually take.

[watercooled]

Just sent a message to the seller to let them know, apparently they were also unaware, are going to investigate and are sending me a replacement to try.

As I said in the message, I wasn't after a refund and was just informing them of the problem, but they're sorting it anyway.

Unfortunately, not many people are likely to check this.

[Manehead]

Nice find. Just shows you get what you pay for... (or not as the case may be)

[watercooled]

Unfortunately, it's still quite possible to end up with rubbish when you pay through the nose for cables.

It would be nice if there were a decent, reliable source for reasonably priced but decent quality cables. I mean there probably are some, but it seems most places just source no-name cables as cheaply as possible and hope they get away with it. But saying that, even well-known brands can produce rubbish cables.

[deejayburnout]

probably a cheap Chinese knockoff.

Seen this sort of cutting corners with fake 'Wylex' RCDs. They looked the part but were build shabby. Most of them didn't trip and didn't even disconnect them from the power.

Always say you get what you Pay for. Were you charged top dollar for them?

[watercooled]

Not exactly; two quid. But whatever you pay, you shouldn't receive fraudulent products.

[deejayburnout]

Not exactly; two quid. But whatever you pay, you shouldn't receive fraudulent products.

Totally agree with you there.

I wouldn't expect £2 cables to be very good though.

[watercooled]

Yeah exactly, it's way below the recommended minimum gauge in the ATX spec. Cable ratings are fairly conservative but I can see some systems greatly exceeding the recommended 3A or so for those cables. I wonder how fire-retardant the insulation is?

You occasionally see people posting on forums with details of melted ATX connectors when their SLI/Crossfire setup pulled too much current through the motherboard, and the resistance in the connector combined with the high current causes it to heat up, so the ATX cable can potentially carry a lot of current.

As Biscuit said, I didn't really think much of it when I went to buy it, you just assume it will be OK. What also gets to me is printing 18AWG on the wire itself when it so clearly isn't. Resistance/voltage drop is also a problem for what I want it for

Edit: ATX spec is 6A per circuit (per wire essentially) which is already way above what I'd trust these wires with, but I expect some enthusiast boards will easily exceed that on at least 12v.

[watercooled]

Bought this one from Amazon: http://www.amazon.co.uk/StarTech-com.../dp/B000FL60AI

18AWG for GND, +5v and +12v
16AWG for 3.3v
20AWG for others, which is fine.

So I'd happily recommend that one over the eBay lucky dip.

[watercooled]

Sorry to keep bumping this thread, but I did a bit of testing outside with a bench PSU.

The wires are ~25cm, and I tried with 5A as it's perfectly reasonable to expect that could flow through a single conductor in some systems, and it's the max my PSU can provide. Voltage drop over the length was about 1.3v initially, but with the wire essentially dissipating 7W or so, it quickly heated up. This increased the voltage drop to around 1.5v after a short while but the breeze seemed to keep cooling it; I left it on for a minute or so but didn't see any smoke, however the insulation was too hot to touch and much more flexible within a few seconds of powering up. It's pretty cold out so that probably helped it; I'm not sure how it would cope in a warm PC case in the middle of a bundle of other cables with possibly twice that current flowing through it.