In a message dated 4/1/2005 12:18:01 PM Central Standard Time,
tr3driver@comcast.net writes:
> >But discussions of fusing quickly evolve into a philosophical discussion
> >about how much you want to spend and how finely defined is the
> >protection.
>
> I don't know about that ... you can do a whole lot of fusing on a Triumph
> before reaching that decision. Just making sure that every wire in the
> harness is protected by a fuse matched to the size of the wire (so that a
> short will blow the fuse rather than smoking the wire) takes quite a few
> more fuses than the factory used.
>
Well, sure, but what isn't fused already? On a TR6 (which is what I am
familiar with) the only things that are not fused are the ignition switch, the
lighting switch the ignition coil and the charging system (including the
ammeter).
Adding the brown wire fuse will give an overall protection to these although
adding a fuse for the light switch makes sense.
But the philosophical discussion comes in beyond that. For example, the fuse
for the green wire feeds the wipers and washer, heater, turn signals, reverse
lights and the gauges. On the one hand this is a good thing because if the
wiper motor causes the fuse to blow you loose the gauges and turn signals and
that is your indication that you need to replace the fuse. On the other hand
it is a bad thing for the very same reasons. It is a very straight forward
operation to split these loads up and power one set off of the spare fuse
position int the four fuse block provided. I did this and although I don't
recall
exactly how I divided the loads up, since they are daisy-chained to a large
extent, cutting one wire separated a group from the rest and a separate feed
powers those (this was written up in 6pack some 12 years ago). But If I were
designing from scratch I would probably divide up the loads more finely. For
example, some cars have separate fuses for the right and left headlamps. This
makes good sense to me. Fusing the Rmain, Lmain, Rdip and Ldip lamps is what
we
would have in a perfect world.
On the other hand, I've had more problems in the TR6 with dodgy fuse clips so
adding more fuses adds reliabiliity issues, too. So maybe fewer fuses is
really better.
This is what I mean by philosophical. ST took the philosophical position
that if there is a problem (EG a wiper motor locks up) it will blow a fuse. If
there is a ground fault (chafed wire touching ground) then you need a new
harness anyway and burning it up is a good way to make sure it gets done. Just
kidding, of course, but adding protection for just such a remote possibility
adds
cost and when you are building cars for a very competitive market it is an
expense you can't afford.
We are not so constrained but we are frequently constrained by not wanting to
rewire the the car. But splicing in fuses is an option but the question is
how many fuses and what loads AND what action is to be taken when a fuse blows.
Fewer fuses means replacement is more urgent but having spare fuses and a
little bit of savy makes that less of a problem.
I guess the real answer is: It depends.
Dave
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