a wiring

[amberteresa]

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

thanks for ur care

 

[Weight]

Does not really matter for the operation of the pump. That is how most door light switches work. But it is better on the positive to isolate the potential for a short. Don't forget a fuse to protect the wire.

 

[wayne49]

Negative switching, wiring the switch to ground, avoids shorts and utilizes less wire. One wire from pump negative to the switch. the other side of the switch is to common ground. No fuse is needed for the switch run.

 

[Weight]

A fuse is not needed for any negative. A fuse is always needed on a positive even if the negative has a switch. What keeps the positive from shorting if using a negative switch? I would much rather have my pump switched on the positive. Some one explain how negative switching uses less wire?

 

[Low277]

In AC power wiring the ungrounded conductor/s are usually switched, there are times that the grounded conductor associated with the ungrounded conductor is also switched as in a 120 volt gas pump. I have seen many DC circuits with the switching in the ground wire, there must be a reason although I do not know or remember what it is?

 

[DannyB1954]

With electronics they sometimes switch the negative side of a circuit because the voltage will drop going through the load. This reduces the voltage going through the electronic switch.

In vehicles they swith the dome light circuit with the grounds because there are multiple doors and it would be harder to wire power to and from these locations. If any door opens, the switch closes and the circuit is complete,, the light comes on. If in ths case these switches were on the positive side, they would have to run power to the switch and then back to the load, (twice the wire).

For about everything else where there is only going to be one switch, you probably will want a fuse then a switch on the positive side. This way if you wanted to work on the load and not worry about shorting it out, you could just turn off the switch instead of having to pull a fuse.

 

[Weight]

Danny gets it.

 

[MikeL]

If you will have multiple pump switches then it is better to switch the ground wire. If only one switch then either. Always have a fuse on the positive side located at your positive distribution box or as close to it as possible.

 

[Weight]

A pump is a heavier load than lights. A pump has inrush current. It is never better to switch the negative on a pump.