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Burnt wiring
james h - 23/3/09 at 02:13 PM

I need a wiring expert here...

Is this connection enough to cause the damage in the following pictures?

Bad wiring connection?
Bad wiring connection?


Damage:

Burnt wire
Burnt wire


Burnt wire into loom
Burnt wire into loom


I got my car wired up by an autoelectrician a little while ago.
I had just got to the stage of starting the engine. I started to attach the battery, but when the second lead was attached to the battery there was a nasty 'fizzle' noise, and smoke. I immediately took one of the leads away, and looked at the damage, which you can see in the above pics.

If its not the connection to the thick brown wire (which seems to go to the ignition), then does anybody else have an idea what it could be?

Thanks,

James

p.s. not looking good for SVA now


tegwin - 23/3/09 at 02:17 PM

Wowza... looks like there has been a catastrophic short circuit there!!


rayward - 23/3/09 at 02:26 PM

looks like the smaller (red wire) has a dead short to earth,

due to the fact the main battery cable + its fuse (if fitted possibly 200amps ish) are capable of carrying a lot more current than the smaller cable, the smaller wire has acted as a fuse itself

hth

Ray


james h - 23/3/09 at 02:29 PM

quote:
Originally posted by rayward
looks like the smaller (red wire) has a dead short to earth,

due to the fact the main battery cable + its fuse (if fitted possibly 200amps ish) are capable of carrying a lot more current than the smaller cable, the smaller wire has acted as a fuse itself

hth

Ray


So the smaller red wire is too thin then? Bah, I was so looking forward to getting the engine started!!

James


scotlad - 23/3/09 at 02:30 PM

EEK thats been a nasty short- lucky the lot didnt go up! Do you have a wiring diagram for it? I think it unlikely a connection would do it- more like a wire has been connected in the wrong place effectively putting a dead short on the battery. Its not been going through a fuse either to cause that amount of damage. i would suggest it needs a very thorough look at the way its wired i'm afraid


james h - 23/3/09 at 02:39 PM

It's not looking too good is it? Unfortunately I don't have a wiring diagram for it, I wasn't given one by the 'trician.

James

[Edited on 23/3/09 by james h]


tegwin - 23/3/09 at 02:42 PM

I would have a chat with him... he should sort it as he obviously has made a major cockup!


Paul TigerB6 - 23/3/09 at 02:57 PM

Yikes!!! Nice short there!! The brown wire will be a live feed - i think you will find it runs to the ignition from the starter motor where your main battery feed connects, and there is usually a bunch of brown wires running into your loom on a ring terminal.

As said - seems your electrician has messed up big time there so get him back


Worzey - 23/3/09 at 02:57 PM

I know its stating the obvious but you did connect the battery the right way around?


james h - 23/3/09 at 03:03 PM

quote:
Originally posted by Worzey
I know its stating the obvious but you did connect the battery the right way around?


Yep, but I can see where you are coming from, I have done silly things like that before, but unfortunately thats not the case here!

James


rayward - 23/3/09 at 04:02 PM

the smaller red wire is probably the correct size in a "non fault" situation

the fact is you have what looks like a dead short to earth, the point of the fuse would be to blow before the cable melted

as said above, i would be on the phone to the guy who wired it

Ray


rusty nuts - 23/3/09 at 07:08 PM

Agreed, the electrician should sort it out if you haven't altered anything.


james h - 23/3/09 at 07:51 PM

Yeah, I have gone nowhere near the wiring. Too scared!