Where should I put the in-line fuse? (Fog lights)

JohnCleary · 15-10-2005 11:43am #1

I was wondering where should I put the in-line fuse for my foglights?

My setup is... Live from the battery to relay, live from relay to fogs.

So, should I put it between the battery and the relay, or between the relay and the actual fogs?

murphaph · 15-10-2005 11:47am

It makes little difference as the current at any point in a series circuit is the same as at any other point (cos electrons can't practically escape the wire), but it would blow a tiny fraction sooner if put between the battery and relay, so stick it there.

JohnCleary · 15-10-2005 11:52am

Cheers,
From a physics point of view I know it makes little difference... It's the NCT im thinking about (Next week)

Thanks

murphaph · 15-10-2005 12:01pm

Just thinking about it a bit more, it's definitely better nearer the positive terminal of the battery, as in a vehicle even the wiring to the appliance being protected could chaff (due to vibration) and short to the chassis (or something else) causing an effective short circuit across the battery terminals which could easily result in a fire (assuming negative earth vehicle). If the fuse was after the point of chaffing the short would not be protected against, so to minimise risk, the closer to the battery the better.

JohnCleary · 15-10-2005 12:14pm

That does make sense actually... Just wired it up there so unless theres a short in the wire between the battery and fuse (15cm) I should be safe!

AMurphy · 19-10-2005 12:31am

Put it between the battry and the relay. If you put it between the N/O (87)contact of the relay and the lights and for whatever reason the N/C (87a) contact of the relay gets shorted you are going to burn wires of draing the battery.
thus by placing it before the relay and close tot he battery, the relay & wiring has more complete protection.

Where should I put the in-line fuse? (Fog lights)

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