IEC 320 C14 Strange Wiring in Device From Japan

[ambd1]

Hi,

I hope you are well. I am new to the forum, so I thank you in advance for you help.

I have a tube amplifier from Japan that came with a very strange wiring in a fused power switch IEC 320 C14. I am located in the United States. I have already dealt with the difference in voltage between Japan and the US, but I am having trouble understanding why the power switch came wired in this strange way.

This is the front side of the fused power switch.

Please find below what I believe is the correct wiring for a fused power switch IEC 320 C14 for the United States.

And, below is the wiring for that power switch in this Japanese amplifier. I have marked some connections with yellow and red, only as reference to the cables coming from inside the amplifier, as I do not know yet which one is neutral and which one is hot.

The fact that the jumpers for hot and neutral coming from the IEC do not go to the same positions (as per the correct wiring) on the switch side would only matter if this switch when OFF only cuts the live/hot wire connection, right? If the power switch actually cuts both, neutral and hot, when OFF then it does not matter where the jumpers go on the right side, as long as both go on the narrow (lower) pair of electrodes, is that correct?

But, why the cable in yellow is connected to the fused hot? sort of bypassing the power switch? I know Japan current is mostly not polarized, but in the United States, what would be the correct way of wiring this for the amplifier?

Any help would be greatly welcome.

Thanks,

Alan

 

[Diver300]

It's usual to have the fuse and switch in the live side, but there will be no difference in behaviour if one or both of those is in the neutral connections. If the neutral is turned off by a switch or by a fuse, the whole mains side will be live, but unless there is a problem with the isolation, that make no difference.

Many mains power connectors are not polarised. Mains connectors in much of Europe are not polarised, and the C7/C8 connectors aren't polarised. Bayonet lamps aren't polarised. If there is ever a fuse or switch after a non-polarised connector, the switch and fuse can end up on the neutral side.

If unpolarised connectors are not likely to be used, there is no incentive for a manufacturer to keep the switch and fuse in the live side, as the user can just plug it in the other way round.

The lamp need both live and neutral connections to work, so if the switch contains a lamp, the assembly will need both live and neutral connections.

The switch can be double pole to isolate both live and neutral.

In the end, as long as the switch and the fuse are both in series with the supply, it doesn't matter which lead they are in. If you want to rewire the back of the inlet to keep the fuse and switch in the live side, go ahead.

 

[ambd1]

It's usual to have the fuse and switch in the live side, but there will be no difference in behaviour if one or both of those is in the neutral connections. If the neutral is turned off by a switch or by a fuse, the whole mains side will be live, but unless there is a problem with the isolation, that make no difference.

Many mains power connectors are not polarised. Mains connectors in much of Europe are not polarised, and the C7/C8 connectors aren't polarised. Bayonet lamps aren't polarised. If there is ever a fuse or switch after a non-polarised connector, the switch and fuse can end up on the neutral side.

If unpolarised connectors are not likely to be used, there is no incentive for a manufacturer to keep the switch and fuse in the live side, as the user can just plug it in the other way round.

The lamp need both live and neutral connections to work, so if the switch contains a lamp, the assembly will need both live and neutral connections.

The switch can be double pole to isolate both live and neutral.

In the end, as long as the switch and the fuse are both in series with the supply, it doesn't matter which lead they are in. If you want to rewire the back of the inlet to keep the fuse and switch in the live side, go ahead.

Thanks for your help.

But, and I apologize if this should be evident for me, so you are implying that in this case the red cable is the live/hot, right? Because if the yellow cable is live/hot then when the power switch is in the OFF position, the yellow cable will not be affected by the switch since it is not connected to it.

And, then, what would the safe/proper way to wire this to be used in the United States?

Thanks,

 

[Diver300]

if the yellow cable is live/hot then when the power switch is in the OFF position, the yellow cable will not be affected by the switch since it is not connected to it.

And, then, what would the safe/proper way to wire this to be used in the United States?

The if the yellow wire is live / hot, and the switch is off, the yellow cable will not be affected.

However,
1) the appliance will be turned off as there is no return path
2) It doesn't matter that all the live / neutral connections are now live because you should never rely on a switch to make stuff safe to work on. There is no substitute for unplugging.

 

[Diver300]

And, then, what would the safe/proper way to wire this to be used in the United States?

Any method that has a fuse and a switch in circuit is safe and proper. Either the fuse or the switch can turn off the appliance, and all of the hot/neutral wiring should always be considered live unless unplugged.

I suppose that the best would be a polarised plug, a double pole switch and a fuse in the live, but there is no practical advantage.