switch

[IanC]

In installing a switch for the water pump, does it matter if it is on the positive or negative wire?

 

[Optimistic Paranoid]

In installing a switch for the water pump, does it matter if it is on the positive or negative wire?

There's no reason why it wouldn't work either way.

The conventional "standard" is that all switches and fuses should be on the hot wire.  The conventional "standard" is that red wires should be hot and black wires should be ground.  Would it still work if you reverse those colors?  Sure.

The main reason for wiring to the conventional "standard" is so the next guy who comes along and has to work on it doesn't have to scratch his head and wonder "what did that idiot do?"

If that's not a concern, then go ahead and wire to the "Ian standard".

 

[IanC]

If that's not a concern, then go ahead and wire to the "Ian standard".

Thanks. Trouble with the Ian standard is that he WILL  be the "next guy that comes along", and he usually doesn't even remember what the heck he did an hour ago - lol

 

[Almost There]

Thanks. Trouble with the Ian standard is that he WILL  be the "next guy that comes along", and he usually doesn't even remember what the heck he did an hour ago - lol

BTDT

In which case labeling and/or using conventional wiring practices makes it easy for someone else to help you figure out what you did...

 

[TMG51]

In vehicles, items are frequently switched on the ground side. The reason being if you switch the hot side, and the body of the switch has metal parts, and you somehow touch a conductive item to the vehicle body and the switch body... direct short.

 

[ccbreder]

Put the switch on the un-grounded wire, usually positive in 12 volt systems. Most automotive circuits are switched on the positive, unless it is a low currant control device.