conFUSEd about sizes

keynsham1 said:
I thought a relay in a lighting circuit was just to stop the current flowing through the switch, in which case it will have no effect on the current and hence temperature at the fuse?
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Not if you use the system as it's wired as standard, but remove the feeds to the headlights, and use that to switch the relays, which have their own fused supply from elsewhere.
 
harveyp6 said:
keynsham1 said:
I thought a relay in a lighting circuit was just to stop the current flowing through the switch, in which case it will have no effect on the current and hence temperature at the fuse?
Click to expand...

Not if you use the system as it's wired as standard, but remove the feeds to the headlights, and use that to switch the relays, which have their own fused supply from elsewhere.
Click to expand...

^^^WHS

Relays consist of 2 independent circuits, the switching circuit has minimal current draw and is isolated electrically from the load circuit.
 
The real problem with those 30mm fuses is not so much that they are short but that they are thinner than the 32mm. So the fusebox blades don't grip them very firmly. It's dificult enough to spot the difference between 30 mm and 32 mm unless you have them side by side, the different diameters are almost impossible to spot! So I tend to use the 32 mm nomenclature as shorthand that people can understand relatively readily.

I'm fascinated by the appearance that there have been 30 mm fuses in there from new. Is this perhaps an error that has occured in NZ? I don't have any cars readily accessible to look at in the UK. All the reasonably close cars have the series 1 style fusebox arrangement. And very few have enough history to be able to conclude that fuses are as original.

I certainly agree that the quality of the joint between the wire and fuse holder blade on the back of the fuse box is a critical feature. I've always viewed it as a combination of the fuse and the joint as leading to disaster.

At the end of the day, though, the real underlying problem is the melting point of the plastic of which the fuse box is moulded. So the real fix is to change the fuse box for a modern one!

Chris
 
Over a period of time, the resistance between fuse and holder increases as the brass holder and nickel fuse cap tarnishes; also fuseholder tension will decrease as fuses are levered out and put back over the years.

One major drawback of the series 2 fuse box, IIRC, is that the main beam and flasher are each powered through a single side of the same holder or did I dream this in a previous life? :?
 
Maybe the shorter fuses have been OK if installed "centrally" , only causing trouble if they are fitted with one end right down and with a poorer connection at the other end ? Just a thought
These fuse boxes are 40+ years old and if one that age was fitted in a house it would have been replaced long ago !
 
One major drawback of the series 2 fuse box, IIRC, is that the main beam and flasher are each powered through a single side of the same holder or did I dream this in a previous life?
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No, you didn't dream it. At least on my S2, that's how the main beam supply and the flasher supply to the main beam fuses are connected up.

I once had a situation where I could switch only one pair of main beams on and the flasher didn't work at all. Removing the x2 main beam fuses, squeezing the contacts back together and inserting correct 1.25" (31.75 mm) fuses made everything work again. I think that out of a total of x4 fuse holder sides, only one was allowing current to pass.

I wonder if anyone has tried the mod of commoning together all x2 sides of the main beam fuseholder contacts on the supply side? I am thinking this would significantly increase the contact area on the fuseholders and reduce the heat build up on the holders and surrounding plastic? It might be an easier mod than fitting relays that keeps that wiring almost standard?
 
Chris York said ;

I'm fascinated by the appearance that there have been 30 mm fuses in there from new. Is this perhaps an error that has occured in NZ? I don't have any cars readily accessible to look at in the UK. All the reasonably close cars have the series 1 style fusebox arrangement. And very few have enough history to be able to conclude that fuses are as original.
Click to expand...

Looking at the NADA spec cars (which were the first production cars to receive the new-style fusebox(correct me if I'm wrong) most of the fuses have been replaced in the most original car here but in the cover are three spares. 35 amps, 15 amps and 10 amps and those are always short lucas fuses of about 26mm which doesn't add up whatsoever. They don't fit properly (no CLICK) and make a contact on either side (in- output) on about 50% percent of surface area of the clips..

Andries
 
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