PSU Improperly connected from factory!?

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PSU Improperly connected from factory!?

Post by brutecai62 » Tue Nov 20, 2018 9:09 am

My A30 power supply died on the 2nd day of printer dc output whatsoever. was going to hook up a new one, but noticed on the original the L and N wires were reversed...verified 2 ways:
1. when powered on there is 120v between N and Gnd, negligible voltage between L and Gnd. (according to the labels on the power supply).
2. verified continuity between the N terminal on the power supply and the L (small prong) on the power cord.

I'm assuming I should switch those when connecting the new power supply, however the part I'm not sure about are two very small gauge wires that were attached to the N and L terminals of the power supply. Not sure what the wires are for, but the question is should I also reverse those, or does it matter? Originally the small blue wire was on N and the small red wire on L. The input power wires from the power plug were brown and blue with blue going to N and brown going to L...

perhaps the connectors were reversed on the power plug? Delivered from the factory, the configuration on the main power wires was:
brown - connected to L on power supply, connected to N on power cord
blue - connected to N on power supply and L on power cord
Yellow - connected to Gnd on power supply and Gnd on power cord.
Haven't checked if the connectors are all the same, but if so maybe I should just switch the L and N connectors coming off the power plug and leave everything else as it was?

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Re: PSU Improperly connected from factory!?

Post by _kaktus_ » Wed Nov 21, 2018 12:45 am


In order not to make a mistake, we first have to make a clear agreement on the markings and colours of the cables.
N - blue - neutral
L - black (or brown or grey) - phase
PE - yellow-green - earth (protective wire)

For me, GND refers to DC and not AC circuits and these terms should not be mixed with each other.

For safety reasons, it is very important that the yellow-green wire is connected to the PE terminal.
This is a guideline.[/u]

Now, underestimating everything else, we can conventionally say that the PSU should be indifferent whether you connect a neutral or phase cable to the N terminal. And the same applies to the L terminal.

Because how can you be sure that the wires are connected to the wall socket in a way that ensures the required polarity?

Of course, from your side, you can make sure that everything is connected as it should be. And let's stick to that.

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