25 replies to this topic

[tiger99]

Well, fusing the headlights is going to use four of your ten fuses, because the dip switch is single pole so you can only fuse downstream of it. You can get it down to two, if you use an excessive number of relays. How you allocate the fuses is a very big question, with no "right" answer, just some that are ok, and some that are not. FRor example, diagram 18 in Haynes shows a layout which uses 8 fuses, if you start with that, get rid of the radio, split the side/tail into left and right, and add fuses for fogs and spots, you will have used all 10.

[Old Bob]

Well, fusing the headlights is going to use four of your ten fuses, because the dip switch is single pole so you can only fuse downstream of it. You can get it down to two, if you use an excessive number of relays. How you allocate the fuses is a very big question, with no "right" answer, just some that are ok, and some that are not. FRor example, diagram 18 in Haynes shows a layout which uses 8 fuses, if you start with that, get rid of the radio, split the side/tail into left and right, and add fuses for fogs and spots, you will have used all 10.

Guess it's get out a pencil and a big sheet of paper time.

Cheers,

Bob

[MRA]

Remember that the fuse is there to protect the wiring NOT the electrical kit hanging off it !

Most modern cars use a hierarchial electrical system, lights are on different fuses, but a close look at the Mini wiring diagram will that they are not fused as standard.

You could create a seperate lighting system so that if all else blows you still have lighting, pay very close attention to ground points, if if you are using any systems that run higher than 12v such as coils and HID lighting then segregate the ground points.

this may save your life so be careful and do the job right.

99.999% of commercially available wiring harnesses do not use solder for very good reasons. however they also have the use of the correct crimping tooling for the terminals used.

Do not use those red, blue & yellow butt splices or terminations as they don't last and are less reliable, scotch locks should be banned, these are the IDC (insulation displacement connector) types that can be used to join a wire to another wire, they only work on BT installations where there is little or no vibration which is unlike your average Mini

[maccers]

I think this might be from the link that was on the first page. Its from Wiki:



 fuse.JPG   38.78K   7 downloads



There seems to be an instant blow and a continous blow rating here. Whats the difference, a few seconds or longer?

Edited by maccers, 30 January 2013 - 11:25 AM.

[MRA]

not sure what a continuous blow rating is ?? blow in this case has a finite time period so by definition cannot be continuous.

[maccers]

This is from the same article on Wiki:

Lucas fuses have three ratings; the continuous current they are designed to carry, the instantaneous current at which they will fuse, and the continuous current at which they will also fuse. The figure found on Lucas fuses is the continuous fusing current which is twice the continuous ampere rating that the system should be using; this can be a source of confusion when replacing Lucas fuses with non Lucas fuses.


Here is the link:

http://en.wikipedia....ive)#Lucas_type

I know some things on Wiki are not always spot on.

[tiger99]

The Wikipedia article is reasonable, except that there is the dilemma of what is meant by "instant"? You will need tens of thousands of amps to blow one in nanoseconds, for instance. For our purposes, it would be reasonable to take it to mean blowing in less than a second.

[maccers]

So on that table the continious fusing would mean what has been said here, Blow rating. And the column in the middle is something causing it to pop faster than the blow rating.

[Dan]

You can assign as many values as you like really. All fuses have a chart that shows their failure time against load, you could pick any point on that graph and say that was an important value. It's normally not. The continuous rating is the current that takes more than a certain amount of years (can't for the life of me remember how many now) to reach failure, the instant rating is the first sensible value that will cause failure in under 5 seconds. Obviously in reality that would tend to be some ludicrous number of decimals but they try to quote it as a sensible figure. Between those 2 figures there is a curve and the closer you get to the instant value, the faster the fuse will fail. The problem is that as you get into the range where it's taking a few days to fail the fuses tend to heat up dramatically. I have known poor fuse choice to start fusebox fires in this way. So only use fuses at or below their rated continuous current. For inductive loads such as motors (fans and others) you need to consider start up current also, but if that is as high as twice the continuous current for the device (and so causing failures) then it's not the sort of item you should be trying to protect with dumb fuses!

[maccers]

I always thought it was the wiring you are trying to protect, not the end device. I mean if a radio or cb or something is drawing over what it should, its probably knackered anyway and easier to replace than wiring loom, and of course, no one wants a fire.

[Dan]

Yes you are quite right, poor choice of words. Sorry.