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Live feed to Ignition
The Doc - 3/3/07 at 07:27 AM

Hi,

Should the live feed to the ignition (coil) be fused?


rusty nuts - 3/3/07 at 07:59 AM

No


RazMan - 3/3/07 at 08:43 AM

Eh? Surely every feed should be fused - my coil has a 10A fused feed anyway.


nitram38 - 3/3/07 at 08:53 AM

Yes it should be fused.
Your ignition is a component and needs protection.
If it developes a fault (dodgy coil?) it is better the fuse blows rather than your wiring catch fire.
Batteries can supply hundreds of amps in a short. My oddessey battery can supply 680 amps !
Therefore a dead short will set fire to your wiring.
Even if you have a 50amp main fuse on your loom, your 10amp wire will burn before that one blows!


rusty nuts - 3/3/07 at 09:12 AM

How many main stream manufacturers use a fused ignition?


nitram38 - 3/3/07 at 09:16 AM

quote:
Originally posted by rusty nuts
How many main stream manufacturers use a fused ignition?


Pass, I am not an expert on manufacturers but I am an Electrician !
Check your fusebox on your tintop.
I have a Previa and it has a fuse that includes one that covers ign.

[Edited on 3/3/2007 by nitram38]


stevetzoid - 3/3/07 at 09:22 AM

Hi all, At the end of the day it is wise to protect all circuits with a fuse to prevent fires on faulty components or wiring, there is no reason not to do it and several circuits can be put through one fuse to minimise the number of fuses required. As stated earlier it is better to have the fuse blow than to burn out the wiring. the only cables usually without fuses are the main power cables from the battery and alternator. Better to be safe than sorry.
Regards Steve Evans.
Control Systems Engineer.


RazMan - 3/3/07 at 09:23 AM

The idea of not being able to isolate the coil would be quite scary imo. As Nitram says, if it develops a fault I would rather have a 10A fuse blow first, giving you an opportunity to zoom in on the problem without having to check every other circuit in the car (if the main fuse blows everything will be dead)
Even mainstream manufacturers sometimes put a dirty great fuse close to the battery in case of a short between battery and fusebox, esprcially if the battery is at the opposite end of the car (my Beemer for example)


[Edited on 3-3-07 by RazMan]


TangoMan - 3/3/07 at 10:12 AM

Personally I would fuse it.

Don't take what manufacturers do as being the right way.

I work with several manufacturers and when you see how many new vehicle fires they have which result in recalls you would be alarmed.
I even saw 1 example of an electric fan not being fused, on a very high volume model, and then the fan was turned upside down to use the same part on another model. This left the drain hole at the top.
Guess what happened when the water got in
This was covered extensively by the press a couple of years ago.

Manufacturers are using new products which have been extensively tested so they feel comfortable cutting corners to save millions on volume production. It still goes wrong though.
Why cut corners in the first place if for your own use at little cost.
Do it right and fit a fuse.


Hellfire - 3/3/07 at 10:39 AM

Fused... for the price of a fuse connector and fuse is it worth not doing it.

AFAIK every bike (BEC) has a main fuse to protect everything electrical on the bike.

Steve


BenB - 3/3/07 at 01:38 PM

After all, a coil is a mass of wires sitting rigt next to each other of differing voltages... and many were designed and made by Lucas (who invented the short circuit)....

It's not as if a fuse is massively heavy.... Worst case scenario of having one- it blows and the car stops... Worst case scenario of not having one- coil turns into a bar heater, catches fire, burns through the fuel line and its Cillitt Bang time...


C10CoryM - 3/3/07 at 03:12 PM

Coils can short to ground when they fail. You definitely want them to be fused in case that happens.
On most cars the only un-fused circuit is the starter main cable.