Blowing Main Fuse

[rawd]

hey folks

recently had some alternator charging woes so removed the wires on the back of the alternator and reconnected to check if that was the problem. ended up putting a spacer on the bolt that the lugged wire connects to (see bolt circled in image below) as it was missing and the lug was moving around a bit.

i did this all with the ground cable disconnected from the battery. when i put it back on, the ground cable sparked on the neg terminal and blew my 75A main fuse. car still starts and stuff but electrical shit in the car does not work. got a mate's fuse and it did the same thing - blew it up (sorry joey if you are reading this).

anyone have any ideas what it could be? i didn't change anything in the car while fiddling with the alternator. battery, alternator or electrical wiring in the car?

i used a metal spacer from the inside of a popped bearing - could the material that this is made of make any difference?

also, where is the best place to get the 75a fuse and approx price?

thanks in advance.

Edited November 3, 2009 by rawd

[Jack88]

No need to remove the neg on the battery while doing that as no current flows through the alt when the cars not running.

All i can think of is the spacer you used is too big in diamater and its shorting out on the case of the alternator. But if that was the case it would fry when you started the car, not when you reconect the earth back up. It is normal for the Lead to spark a little bit when re connecting up a batter as the elec system in the car will draw a current for a moment.

If i were you i would remove this spacer you put on or atleast check to make sure its not shorting out on the case. Make sure the plug is still pluged in on the back of the alt. Other then that you havnt done anything to cause a problem so without seeing it i cant help you any further.

Oh and any autobarn store should have thos fuses in stock. cost you a couple of $$

Edited November 3, 2009 by Jack88

[rawd]

cheers jack

i agree, been reading up since i posted this and only thing i can think of is the frayed wiring or the spacer is causing a short.

[rawd]

Update: Used a smaller spacer and the problem was fixed. Had to make sure the spacer was properly insulated.

Thanks for ya help.

[Carbon 34]

Update: Used a smaller spacer and the problem was fixed. Had to make sure the spacer was properly insulated.

Thanks for ya help.

never run a car without the ground on the battery hooked up or remove the battery wires while the engine is running, it will fark up a lot of stuff by floating the ground path.

FYI:the factory uses special NON-METALLIC spacers on alternators to stop the grounding out of the casing to the positive charging wires which blew the main harness fuse. the little red ones that kinda feel like paper ???