basic electrical question

[Anonymous]

I seem to notice that our electrical experts always seem to suggest to install a switch on the ground wire of a device (between the device and the ground) i.s.o. on the +wire. I'm just wondering; Is there a reason for this preferrence or is it just all the same ?

Digno

[redliner1973]

They probably refer to that due to the fact that voltage actually travels FROM the negative(grnd) TO the positive, by putting a switch on the neg side, you make a device safer by not allowing voltage to find a shorted path through the device, but rather by shutting it off at the source. :twisted:

[kz]

I always thought that it depends of the application.

Example:

1. The headlight switch is connected on the ground wire.

If there is short to ground at the switch-connection (connections are often the reason for short circuits), the light is always on, meaning you can always drive your bike home safely.

2. The headlight switch is connected on the positive wire.

If there is short to ground at the switch-connection the fuse blows, or your harness burns up.

If the application is something you DON'T want to run all way home, like the starter, it is better to put the switch into the positive wire and let the fuse blow.


Depending on what method you use, if the frame itself is the "ground-wire", you can save one wire if you put the switch in the ground wire.

Just some thinking......

[earlfor]

Re: basic electrical question

Standard electrical practice is to install a switch on the hot (+) side.

Earl

I seem to notice that our electrical experts always seem to suggest to install a switch on the ground wire of a device (between the device and the ground) i.s.o. on the +wire. I'm just wondering; Is there a reason for this preferrence or is it just all the same ?

Digno

[kz]

Earl,

As far as I know, I agree,

Putting the switch on the negative - side, was done in i.e older cars like Volvo up to approx. 1970, horn switch, door light switches, points etc.

Today you always use an extra negative ground wire anyhow.

[earlfor]

Well Surprise me Karl. I thought positive grounded cars were not made after the 50's. :-) :-)

Earl

Earl,

As far as I know, I agree,

Putting the switch on the negative - side, was done in i.e older cars like Volvo up to approx. 1970, horn switch, door light switches, points etc.

Today you always use an extra negative ground wire anyhow.

[Hap Call]

Well Surprise me Karl. I thought positive grounded cars were not made after the 50's. :-) :-)

Earl

Earl,

As far as I know, I agree,

Putting the switch on the negative - side, was done in i.e older cars like Volvo up to approx. 1970, horn switch, door light switches, points etc.

Today you always use an extra negative ground wire anyhow.

I have a '66 MGB that is positive ground - or was positive ground before I modified it.

Hap

[earlfor]

Hmmm, I wonder why it is that I'm not surprised you would be driving a reverse polarity car. :-) :-) Yessir, if anyone is going to have their wires crossed, its going to be Hap. :-) :-) :-)

Earl

I have a '66 MGB that is positive ground - or was positive ground before I modified it.

Hap

[Anonymous]

When it come right down to it, it doesent matter where you put the switch because if there isent a complet path then the electrons wont flow

[terrybird]

Yea, but can you argue with KZs logic?

[focus frenzy]

Earl,

As far as I know, I agree,

Putting the switch on the negative - side, was done in i.e older cars like Volvo up to approx. 1970, horn switch, door light switches, points etc.

Today you always use an extra negative ground wire anyhow.

volvo still uses switched grounds for many of it's circuts in the heavy trucks, IE the heater/ ac blower is controled by running the ground through the speed resisters and switching the ground, 1 hot wire, 4 differant grounds.
vehicle horns are still controled by the ground circut, some dirrectly, some through a relay.

[kz]

Earl,

Volvo always had negative ground, but english cars like Ford Cotina and as Hap wrote MG had positive ground even in the late sixties.

What I ment to explain is the way Focus Frenzy descirbed it, the benefit is to save wires. (I believe).

The english bikes also had the gear shift lever on the right side and in GB they still drive on the left side of the road. 8O

Positive ground is normally not a problem, the problems start as you try to connect i.e. a car radio....

[Anonymous]

......and in GB they still drive on the left side of the road. 8O

The primary reason for this is to confuse vacationing Swedes. :twisted:

[redliner1973]

It shouldn't be too much of a problem considering most of us throw out the instructions first anyhow!!! :twisted:

[kz]

......and in GB they still drive on the left side of the road. 8O

The primary reason for this is to confuse vacationing Swedes. :twisted:

You sure do, especially as the steering wheel is on the right..

So the solution is:

Always take your GS, if you want to drive on your holiday in GB.