Why don't manufacturers use standard color coding when it is available?

[BobA]

Ok this should have been a no brainer.   The power supply for my ATA/SATA interface died.  I  use it alot to transfer data from disk drives that I don't want to put into a USB to SATA case and for older ATA drives.  So I cut the connector off of another PS that had a din connector on it. I get red yellow and black wires and then I cut the molex style connector off the old PS and it has red white and black.   So I guessed at red to red, yellow to white and black to black.  WRONG. When I check the connector with a volt meter the red was 12V  white and yellow 5V and gnd was gnd.  These were little switching PS bricks that you cannot open.

If you look at any molex drive connector in a PC red is always 5V and yellow is 12V.  WTF?

Then I looked at a fan with an adapter.  It has red and black wires but the adapter feeds the red from a 12V yellow molex wire. Of course it is  a 12V fan but why use red and black unless they are saving a couple of pennies?

[boardjunkie]

'Cause no law says they *have* to.....

[SavannahLion]

'Cause no law says they *have* to.....

It's not law, but doesn't ISO have something about it? Or maybe it's bundling and banding, not usage..... nevermind.

In any case, one of the earliest lessons I learned about electricity is, trust what the voltmeter says, not what the color code says.

[BobA]

Yes always check with a voltmeter.  That is how I found 5V and 12V switched on the connector.

[SavannahLion]

Yes always check with a voltmeter.  That is how I found 5V and 12V switched on the connector.

Yes, always poke it before committing.

[VanillaGorilla]

I usually just lick the wires. 12v is always tangy-er!

[Mario]

I usually just lick the wires. 12v is always tangy-er!