Double ground wiring to control panel?

[DaveJ-UK]

Every micro switch on my (pre-wired) control panel of my cab has 2 wires to each common point. Both wires take exactly the same route, and terminate at the molex connector. Only 1 wire is on the other side of the molex connector. There is a pair of ground wires for each players controls.

It only has 2 buttons per player at present and I'm wiring another 4 each to make it 6 buttons per player.

My question is, do I need to wire the extra buttons in this way? I know it will work with one, but I can't see any reason anyone would wire two?

It's 16/0.2 wire if that makes a difference.

[hatrick]

You should not need two ground wires per switch. If they terminate at the same spot, then it is just redundant wiring. Any buttons you add should only need one ground wire.

[pmc]

I wonder why someone wired it like that? Doesn't seem to make any sense at all.

[paigeoliver]

I wonder why someone wired it like that? Doesn't seem to make any sense at all.

Yes it does. If the operator simply runs a single ground wire to the panel then any break in that wire takes out the panel and results in a service all.

If he runs a loop that hits every switch and then both sides of the wiring go back to the board then it takes 2 breaks for the machine to need a service call.

If he runs a double loop then the machine will probably NEVER need a ground related service call. It would take 4 breaks all centered around a single switch, and then only THAT switch would die.

[DaveJ-UK]

True, but it's kind of like keeping 4 spare tyres and 20 gallons of petrol in the boot, just in case you get stuck in the middle of no where with 4 flat tyres and an empty tank.

I guess I could do a loop though; I have more than enough wire.

[paigeoliver]

I agree, but the difference is that the 4 spare tires and extra petrol cost money and use up the whole trunk of the car. The double ground trick costs absolutely nothing. I'm not sure how common it is, but I have seen it before.