I'm repairing a Kenwood Model 500 amplifier finally after buying it 5 years ago, part of that sale was to take the aftermarket 'audiophile mains cable off' for the seller, however now I've come to put a new one in I'm not sure its wired correctly?
This is double insulated. Neutral is fused not live, not sure this is the way it was from factory? Should this be changed? I'm assuming its the UMX type as its the only one with a 4 amp fuse. On the attached pics 1st is how it is now, second pic could it be changed to this? I am in the UK so 230v
This is double insulated. Neutral is fused not live, not sure this is the way it was from factory? Should this be changed? I'm assuming its the UMX type as its the only one with a 4 amp fuse. On the attached pics 1st is how it is now, second pic could it be changed to this? I am in the UK so 230v
Attachments
Fusing the neutral isn't optimal, but it works. Unless the trafo 's primary shorted to core or to secondary, which is rare to occur.
I would left as is. Unless, you will need to place two fuses identical with their holders between trafo and accesory outlets or place a sufficient large fuse to support extra current drain or refuse to use such extensions any more.
If its double insulated and uses a non polarised twin core mains lead (like a fig 8 lead except now its the mains plug that is reversible) then L and N become meaningless because the end user can insert the mains plug either way around. All that fitting a UK 3 pin plug does is fix the the configuration depending how you wire it.
You could argue that fusing one side and switching the other is at least 50% correct all of the time, which ever way you connect it but because the unit is double insulated to the appropriate standards then that does not matter to the end user. Operationally it is simply a series circuit. Only those who delve inside need to be aware of the risks. The spec of the parts (transformer, switch, possibility of wiring shorts etc) mean there is no risk to the user because those eventualities are designed into the parts spec.
You could argue that fusing one side and switching the other is at least 50% correct all of the time, which ever way you connect it but because the unit is double insulated to the appropriate standards then that does not matter to the end user. Operationally it is simply a series circuit. Only those who delve inside need to be aware of the risks. The spec of the parts (transformer, switch, possibility of wiring shorts etc) mean there is no risk to the user because those eventualities are designed into the parts spec.
Thanks Mooly,
So essentially leave as is? The only difference is a 3pin iec socket has been put in previous to me but earth has not been connected and will not be
Revisiting this now the house is quiet, I don't think this is double insulated. It was supplied with a captive mains cable that was apparently damaged, then replaced by the previous owners tech, again I don't know if it was rewired to how it was originally. I take it this makes no difference to the leave as found as the schematic has no polarity markings? Or does this now pose a safety issue with modern standards?
A new 3 core wire might help if the chassis is connected to earth, if you have electrical noise issues.
If three core wire, fuse is in series with L, not N, 3 pin plug will ensure correct connection.
And a fuse is okay on either side, you cannot control the two pin wiring, in the sense the plug can be put either way.
Move on, if the set is working, enjoy the music.
If three core wire, fuse is in series with L, not N, 3 pin plug will ensure correct connection.
And a fuse is okay on either side, you cannot control the two pin wiring, in the sense the plug can be put either way.
Move on, if the set is working, enjoy the music.
That is what I would do.
The manual shows a two core lead which means it has to be double insulated. It is designed to be safe without the protection of a 3 core lead. Providing the new lead is wired to the correct points (as shown in the manual) then it should all be good.