#2

[DrobinsonPE]

Looking at the picture I think you are fine. If you straighten the wires out in a line instead of looping back with the connectors right next to each other, and you look at the connections from one end I think you will find that the wiring is the same on both sides. wires appear to cross because you have the wiring looped back instead of straight. I drew a picture.

[PhilF]

Originally Posted by DrobinsonPE

Looking at the picture I think you are fine. If you straighten the wires out in a line instead of looping back with the connectors right next to each other, and you look at the connections from one end I think you will find that the wiring is the same on both sides. wires appear to cross because you have the wiring looped back instead of straight. I drew a picture.

EXCEPT, if you compare it to a standard AC cord by ohming it out, it is indeed backwards.

I reiterate, DO NOT use it.

[Xyzzy]

Before we posted here for help we contacted the manufacturer. They claim it is okay.

Here is their response:

Thank you for your patience, we now have an update from our engineering team (PSU).

For ATX psu it doesn't matter which pin has hot or neutral for safety issue.
The switch is just a circuit breaker to disconnect the system from cabling while system is on/off.

The funny part is they don't address the fact that we measured 125V to ground in both switch positions.

[Xyzzy]

Our original message to them:

I traced out the power with a continuity tester on the PSU harness in my case. It swaps the hot and neutral wire and as a result the switch on the back of the case has no effect. This doesn't feel very safe. Can you help?

[DrobinsonPE]

Originally Posted by PhilF

EXCEPT, if you compare it to a standard AC cord by ohming it out, it is indeed backwards.

I reiterate, DO NOT use it.

If I understand the original picture correctly the problem is not in the cable. The problem is that the receptacle is wired backwards. See attached picture.

[Xyzzy]

Are we testing this wrong?

We tested our wall receptacle and our PSU cord.

Blue = Ground
Red = Hot
Green = Neutral

FWIW, in a previous life we took a two-year community college program to become an electrician. We never did use that for a job and we really didn't learn much.

But, we learned three things we will never forget:

1) Be safe!
2) Be safe!

and…

3) Be safe!

If we recall correctly, the NEC was mostly (99%?) about safety. (Our instructor kept harping, daily, on section 250 - grounding - for some reason! It got to the point that the entire class, when asked any non-obvious question, would reply "Grounding! Article 250!")

[DrobinsonPE]

I would think that this is how the connections should be if the cable is wired correctly. You can use your DMM to check the continuity between the two ends of the cables in your picture. You should have continuity red to red, green to green and blue to blue.

is your second picture mirror imaged? Based on this set of pictures the cables might be miswired.

[Xyzzy]

Originally Posted by DrobinsonPE

I would think that this is how the connections should be if the cable is wired correctly. You can use your DMM to check the continuity between the two ends of the cables in your picture. You should have continuity red to red, green to green and blue to blue.

Agreed. What we posted is what we actually measured. We used a continuity check for the cable and an AC check for the receptacle.

[PhilF]

Originally Posted by Xyzzy

Before we posted here for help we contacted the manufacturer. They claim it is okay.

Here is their response:The funny part is they don't address the fact that we measured 125V to ground in both switch positions.

It isn't funny. Their engineers do not know what they are talking about.

The reason you are measuring the 125V in either switch position is because the miswired plug assembly is placing the switch in the neutral line! Fusing or switching the neutral line only is one of the biggest mistakes that can be made in electrical engineering.

Third time's a charm: DO NOT use that cable assembly!

EDIT: OTOH, if you want to take the simplest approach for a fix, cut the receptacle off and splice it back on with the blue and brown wires reversed (black and white wires if made in America, which is highly unlikely). That way you will have it fixed, then you can sit back and relax as you watch that company crash and burn. Pun intended.

[lavalamp]

As long as your EARTH (aka ground) pin is correct you're fine. The case and anything metal you can touch is grounded with this pin.

[PhilF]

Originally Posted by lavalamp

As long as your EARTH (aka ground) pin is correct you're fine. The case and anything metal you can touch is grounded with this pin.

That simply isn't true in the USA.

In the UK, you have 220V mains, meaning 2 "hots", and one earth.

In the US, we have that split into a HOT and NEUTRAL, both are separate from EARTH.

In a 120V appliance, one of the worst things you can do is switch the NEUTRAL line, which is exactly what happens when the HOT and NEUTRAL gets reversed.

Really, guys, I know what I am talking about here.

DO NOT USE THAT CABLE!!!

I hope I wasn't unclear.

Google it, you will find this:

"The neutral wire is connected to ground at the breaker box, which is connected to physical ground nearby. If you switch the hot line and leave the neutral, then the whole device will be at neutral potential. That's OK. If you switch the neutral, then the whole device will be at hot potential. In theory that's OK since all of that is supposed to be insulated. However, stuff happens, and by switching neutral instead of hot you have removed one layer of safety. That is not a good idea."