Classic cars forum & vehicle restoration.

[PACresta]

After a close encounter last weekend when a couple of wires decided to get hot on my PA i am seriosly considering fitting a fusebox. My main concern is, would i be creating a weak point in the wiring. What i mean by that is the fusebox i have, the wires are clamped by a scew type connector (possible trouble spot i thought). Or is this me being paranoid after my dice with near car extingtion? I have been advised to at least "tin" the ends before fitting.

Also any thoughts on fuse rating, i was thinking of putting 8 amp (bullet type fuses) in the lighting circuits, indicators etc. Anything that drags more current to use a 16 amp fuse.

Any thoughts would be appreciated

I found the cause of the problem to be my own silly fault, i had connected the reversing light circuit up. There was no need to as there are no reversing lights on the car, i presumed the wiring was there as an optional extra. I thought i would put the wiring in place for authenticity

Anyway one of the terminals came adrift from the switch and shorted out on the gear linkage

[UKdave2002]

Hi Pete

I am surprised your PA has no fuses are they possibly hidden in a regulator? If not I’d fit some. Regarding you introducing a potential “weak spot” if it’s done properly you should not have any trouble with the additional connections.
I am a fan of tinning where you have a screw connection, the softer solder will “form” round the screw and connector body as it is tightened up, and you are sure that all the strands of wire are conducting current.

With regards to fuse size you need to understand what current is being drawn, so if all your lighting is on one circuit you will probably have;

Main beam 2 x 50Watt bulbs
Dip Beam 2 x 40 Watt bulbs
Tail lights 2 x 5 Watt bulbs
Side lamps 2 x 5 Watt bulbs

Now it is possible that your main beam and dip can be on at the same time for a fraction of a second as the dip switch is engaged so the total power require is the sum of all the above, which is 200 Watts.
So the total current being drawn is 180Wdivided by 12V = 16.66 amps.
As you can see anything less than a 16.66 amp fuse would blow, we also need to add a bit of contingency as the current drawn will be higher when all the filaments are cold, so in this case a 20amp fuse would be about right .

On more modern cars side and tail lamps would be on a different circuit (yours may) and would have thier own fuses

How many different fuses you put in depends on how the car is originally wired and how well you understand the wirring, my Morris 8 has only 2 fuses, 1 for circuits wired through the ignition switch such as wipers, brake lamp and one for things the aren’t, like headlamps, that how they did it in the 30's.

You could add inline fuses on independently on lamps etc but then will have the problem that fuses will be all over the place and a pain to find if they blow.

Hope this helps


Dave

[PACresta]

Thanks Dave, your reply is a big help, my understanding of wiring is limited. There is 4 (factory fitted) inline fuses under the dash, they clip onto the steering column. I was surprised that the circuit invloved was not protected (indictor's, brake lights and reversing light)

From your post i now realise that i need to carefuly check the wiring diagram and assess each fuse rating. I used to run vw beetle's and i will say the wiring was superb as each indivdual circuit was fused.

At least for now i have made a neat repair to the Cretsa wiring, i can ponder the fuse box idea for a winter project.

[Uncle Joe]

Funny thing that you mentioned the VW system. Back in the day, when a Lucas fuse box used to have just two fuses, I remember quite a few people removing it and replacing it with the VW's fuse box, which if I remember correctly had 8 fuses...

PA, why not do the same for a ''period'' upgrade?

UJ

[PACresta]

Yes that sounds like a good idea UJ, will have to look into that one.

[Uncle Joe]

I did a bit of digging into this last night, and came up with a few thoughts.

First off, I found in some old notes that some Vauxhalls had Thermal interruptors instead of fuses. Is that the case with your Cresta?

Second, the twin fuse Lucas fuse box uses 35A fuses. I have a ''wiring in'' diagram for this. I also have the same for the 8 fuse VW fuse box.

Let me know and I can post the details.

UJ

[Brian M]

When I rewired my caravan I wanted to protect every circuit with a fuse and so bought a period fuse box from Holdens.

http://www.holden.co.uk/displayproducts.asp?sg=1&pgCode=084&sgName=Electrical&pgName=Control+Boxes&agCode=0458&agName=Fuse+Boxes

Not totally original for your PA, but better than burnt out wiring or worse.