Amp wiring question

[Alex_225]

Quick question to the more techy ICE people on here.

I've always wired the power cable to an amp with the fuse at the battery end. Usually within a few inches of the battery itself. Now because the Twingo is a ball ache and due to not having a spare fuse, I've had to put the fuse at the amp end.

Now my thinking has always been the reason the fuse is nearer the battery is that if it blows, there's less length of live wire running through the car. Is this generally the only reason? Worst case is I'll pick up a new fuse, chop the wire and crimp in a new one but just wondering. :?

 

[singlespeed]

If the cable insulation is damaged against the chassis anywhere between battery and fuse, you will be calling the fire brigade.

The amount of current battery can give out when shorted is huge. The fuse protects the equipment and also the cable/battery from overload if shorted out

 

[Alex_225]

Thanks for the info mate, that does make sense.

Fortunately, where I've fed the cable and secured it, there's little likelihood of the insulation getting damaged. Think I'll get another fuse fitted down at the battery end haha.

 

[singlespeed]

In my previous job, a Mercedes Vito truck was almost written off due to an un-fused cable.

The starter motor on a trailer was knackered and kept blowing fuses, so the electrician removed it as ordered by the boss, as it was needed for one job. The driver forgot to unplug it as instructed.

Batteries, chassis and engine looms, body ECU, dashboard were all burnt out. Cab mounting locks and suspension were actualy welded solid. Granted the twingo battery is only 1/4 the capacity of a truck, but the cranking amps are still huge.

 

[Alex_225]

The cable is fused mate but at the furthest end. I suppose that only really saves the amp if it shorts out.

Either way I'll get shopping for a fuse and holder to go near the battery now!

 

[Matt]

The cable is fused mate but at the furthest end. I suppose that only really saves the amp if it shorts out.

Either way I'll get shopping for a fuse and holder to go near the battery now!

But if there was enough current to blow the fuse, there's the possibility that the cable could set alight to anything it's near between the battery and the fuse.

This is the reason large fuses are mounted as close to the battery as possible so there is less chance of any damage.

Definitely get the new fuse holder. I think I have one kicking about somewhere that I used to run with my 2kw system if you're interested?

 

[Alex_225]

Exactly what I was thinking, not much good the fuse going pop and leaving the rest of the wire live through the car.

I think I may even have a spare fuse holder somewhere so will look for that. Thanks for the offer though Matt, much appreciated.

 

[Alex_225]

Just fitted one of these little chaps up by the battery so all safe and sound and working nicely

 

[singlespeed]

Good call. Better safe than sorry

 

[Oizo_133]

Alex_225 : where did you put your 12+ cable through, from motor space to the passanger cabin?

 

[Alex_225]

If you take back the carpet in the passenger footwell and look just under the glovebox, there's a big rubber grommit.

I made a hole through that and pushed the wire into the engine bay from there. It's a really big grommit with only one wire going through it to the right so plenty of room for a power cable. Also a good seal so no water leaking.

Only thing I had to do was re-wire a fuse as that wouldn't go through the hole in the gromit. Once the wire was through, I just had to use a coat hanger (wrapped in tape to stop it scratching) and hook the wire up from whre it comes into the engine bay.

Hope that helps mate.

Good call. Better safe than sorry

That's what I thought.

 

[Oizo_133]

Alex_225 ... but you have right hand drive .. so in my case it won't work .. i have left hand drive
i dont have no holes there ..