AC Mains Wiring - Fuse

[GregS]

The schematic I'm working from has the fuse between the power switch and the PT primary. It seems to me that the fuse could be put in one of the wires from the AC cord before the power switch and accomplish the same thing. Also, doing it this way would be less awkward for wiring and require less length of wire - especially since my fuse and power switch are on opposite sides of the chassis.

Is there any reason that the fuse should be in one of the PT primary leads after the switch as in the schematic?

Thanks,

Greg

[defaced]

I would want it between the mains and the switch in case anything happened to the switch.

[GregS]

Ok. Thanks.

Greg

[tubeswell]

What's more, your fuse holder should be wired so that the live end is at the end that is not going to come into contact with your skin if you unscrew the cap and touch the contact while the amp is plugged in and switched on (not that you should be doing that all the time mind you)

[Enzo]

That is why the fuse holders of today have recessed contacts unlike the ones of 20 years ago.

[GregS]

I wound up putting the fuse in after the AC switch. The mains wires move slightly where they enter the chassis when the cord is moved around. With such a short length of wire going to the fuse holder I figured there would be strain on that connection every time the cord moved. There is significant distance and some wire slack going to the switch plus the switch is very solid so pulling on the switch connections won't be an issue. I think next time I will use one of those sockets that the AC cord just plugs into.

The live side does connect to the contact of the fuse that can't possibly be touched from the outside when the cap is unscrewed.

Greg

[tubeswell]

The reason for putting the fuse in before the switch isn't so much that the switch might not be able to handle the wall voltage - the fuse goes before the switch more to protect you than to protect the switch

[GregS]

Another reason might be if the switch somehow developed an internal short such that the hot and return wires from the cord became shorted together. I'm using a quality heavy duty switch so this is not likely.

Greg