BUILD Please review my Intel Skylake FreeNAS build

[TheKiwi]

If you do want the SATA adapters, get crimped not moulded ones.

GOOD

BAD

 

[jgreco]

Yeah, but doing a nice job with the crimper gives you that opportunity for supple, flexy goodness.

 

[jgreco]

If you do want the SATA adapters, get crimped not moulded ones.

GOOD

BAD

Disagree; the good quality moulded ones provide better strain relief.

 

[jgreco]

and while we're at it, those look like IDC style, not crimped, SATA power connectors.

 

[TheKiwi]

Disagree; the good quality moulded ones provide better strain relief.

Disagree. Most power supplies use crimped (or more correctly, idc?) connectors, and the whole fire issue comes from the single-piece moulded ones being bad quality. Look around - the majority of the time people have issues is with the moulded ones (google image search for "sata adapter fire"). They are bad news.

 

[jgreco]

Of course the cheap ones are bad news. I never suggested to use the cheap ones.

IDC is definitely less desirable than crimped. IDC involves slicing through, displacing insulation, and relies on a "spring" effect to maintain a connection to the wire. Conceptually:

This sort of terminal is prone to bad things happening because of mechanical stresses on the wire causing shifting and variations within the terminal, plus the area of the terminal that is actually in contact with the wire is fairly minimal. In the telecom world, generally IDC connections are only considered for solid wire (66, 110, etc) because they're so effing prone to failure with stranded. If you have a right-angle SATA power connector with a little plastic cover on it, that's probably an IDC connector like this:

That's a shitty prebuilt modular cable. The pins used are actually a dual IDC which pierce the insulation in two different places.

Crimped is a whole different ballgame:

where you actually have a large section of the terminal crimped AROUND and into the stranded conductors, plus another section of the terminal wrapped around and grasping the insulation, forming one of the best connections you can get short of soldering.

This is what it looks like:

But the thing with these is that they're still somewhat prone to individual pin rip-out, because there is only a metal or plastic tab holding them in place. By comparison, the moulded ones are held in place by moulded plastic. The good quality moulded ones are by far the toughest customers as connectors go.

 

[TheKiwi]

Of course the cheap ones are bad news. I never suggested to use the cheap ones.

IDC is definitely less desirable than crimped. IDC involves slicing through, displacing insulation, and relies on a "spring" effect to maintain a connection to the wire. Conceptually:

This sort of terminal is prone to bad things happening because of mechanical stresses on the wire causing shifting and variations within the terminal, plus the area of the terminal that is actually in contact with the wire is fairly minimal. In the telecom world, generally IDC connections are only considered for solid wire (66, 110, etc) because they're so effing prone to failure with stranded. If you have a right-angle SATA power connector with a little plastic cover on it, that's probably an IDC connector like this:

That's a shitty prebuilt modular cable. The pins used are actually a dual IDC which pierce the insulation in two different places.

Crimped is a whole different ballgame:

where you actually have a large section of the terminal crimped AROUND and into the stranded conductors, plus another section of the terminal wrapped around and grasping the insulation, forming one of the best connections you can get short of soldering.

This is what it looks like:

But the thing with these is that they're still somewhat prone to individual pin rip-out, because there is only a metal or plastic tab holding them in place. By comparison, the moulded ones are held in place by moulded plastic. The good quality moulded ones are by far the toughest customers as connectors go.

Sure, good moulded ones would be best. But with the amount of bad, underspecced moulded connectors out there I can't recommend letting them near your build.

With IDC and crimped ones you have a better chance (in the current market) of getting a properly designed connector, as long as you don't physically abuse them.

 

[jgreco]

Sure, good moulded ones would be best. But with the amount of bad, underspecced moulded connectors out there I can't recommend letting them near your build.

You already recommended IDC. From my perspective, that's bottom of the totem pole (aside from cheap molded, which isn't even in the running). IDC is most likely to develop a problem after someone wrestles with the cables a few times. Crimped is about the best we can do here in the shop because we lack a way to do injection moulding for SATA.

It isn't just the moulded ones that burn, by the way, they'll all burn. The SATA power connector is a little more prone to arcing due to an imperfect connection, which is basically a precursor to heat and fire.

Looks like a crimped connector to me.

I think the reason we tend to see more fires with the moulded ones is because all the cheap SATA Power "Y's" are moulded, probably with second-rate connectors at that, so suddenly you have start current for two drives worth of drives (4 amps) being pulled through a terminal not rated for much more than that (4.5A IIRC).

And damn it, now I can't find the cite for that. Thought it'd have been listed with the terminals.

http://www.molex.com/pdm_docs/sd/675810010_sd.pdf

Okay well I'm going to grinch at something else for a bit because digging through data sheets sucks.

 

[TheKiwi]

You already recommended IDC. From my perspective, that's bottom of the totem pole (aside from cheap molded, which isn't even in the running). IDC is most likely to develop a problem after someone wrestles with the cables a few times. Crimped is about the best we can do here in the shop because we lack a way to do injection moulding for SATA.

It isn't just the moulded ones that burn, by the way, they'll all burn. The SATA power connector is a little more prone to arcing due to an imperfect connection, which is basically a precursor to heat and fire.

Looks like a crimped connector to me.

I think the reason we tend to see more fires with the moulded ones is because all the cheap SATA Power "Y's" are moulded, probably with second-rate connectors at that, so suddenly you have start current for two drives worth of drives (4 amps) being pulled through a terminal not rated for much more than that (4.5A IIRC).

And damn it, now I can't find the cite for that. Thought it'd have been listed with the terminals.

http://www.molex.com/pdm_docs/sd/675810010_sd.pdf

Okay well I'm going to grinch at something else for a bit because digging through data sheets sucks.

Fair enough. You may be right that cheap moulded ones are just more common. I think we can both agree that the situation with spliters overall is pretty bad.

 

[jgreco]

I think we can both agree that the situation with spliters overall is pretty bad.

No. The splitter ones are the devil's spawn.