The Infamous Series 2 Fusebox

You have performed an excellent job in bringing the fuse box into the 21st century. How long did this take you. Cost and where did you find a fuse box suitable?
It was about 8 hours work. Did most of the cutting and prepwork on the bench. Essential to label all wires. The fusebox was from Vehicle Wiring products, FBB16U, as well as 2m of the red and blue wire 2mm2, (£24), brass tubing from a hobby/modelling shop on ebay, 8mm heat shrink sleeving and a heavy duty crimping tool on ebay for £25.
The most difficult part was getting the wires into the brass tubing and the crimping tool. If the linking wires were longer than I listed in the cutting schedule on the drawing, say 150 to 190mm, it would make the job a bit easier, but then there would be more wire to clip into place.
 
Certainly well worth the time spent and making the car safer from potential fire problems. That's a good shout regarding the brass tubing as I was thinking on how to replicate the joining of wires as I have a problem and need to sort this out and was wondering what would be the best way to join wires together as I am not keen on using bullet connectors behind the dashboard.
Thank you for the udate.
 

cobraboy

Well-Known Member
Just looking at that photo I am wondering how much the clips are helping in that location. The force exerted in that position so low down must be minimal.
I would look at installing all the fuses and then put the clips above the fuse to pull the sides tight around the fuse.

Edit
I am forgetting that the two terminals are maybe not joined at the bottom ? I cannot recall now.
It would be interesting to measure the gap on the one 3rd in from the right at the fuse location, with a caliper, and then measure a fuse to see what the relationship is. The gap looks very wide and the grip maybe minimal ?
 
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jp928

Well-Known Member
Hear what you say about clip placement, but they are fiddly to fit even where i have them, and the chance you could pull the clips to R&R a blown fuse and not lose the clips is zero. I have a replacement fuse block, and the fit of fuse ends in it is very firm. So far my relays for the lights are doing their job, so there is not much need to modify further. Having said that, still looking into a way to fit blade fuses.
This is how I made continental bullet fuses (ceramic body) into blade fuses in the 928. The original clips that hold the ends of the fuses are fitted to a 1/4" male blade on one end, and a 5/16" male blade on the other . 5/16" female spade connectors are thin on the ground, but found enough in the end. I managed to solder the ends of keystone 3557-22 fuse holders onto the relevant spade females. The different colours indicate Amperage. No issues in several years.
 

jp928

Well-Known Member
Did somemore research on fuses . According to wikipedia.....Fuse (automotive) - Wikipedia
Lucas type glass fuses (strictly '3AG', 1/4" dia, 1.25'long) current rating shown is safe continuous , BUT they will melt at DOUBLE that if continous, and blow instantly slightly higher. EG, a 25A 3AG should blow at 50A continuous, or instantaneously at 60A. This I was not aware of, and it might explain why our P6b fuse boards start melting if currents spike. The fuses seem to be adequate, with LH and RH dips on separate fuses, and the inner and outer high beams on separate fuses. Makes me think the melting problem is due to poor contact on the fuse ends, and the crappy way the two sides of the clips are not properly connected. The ratings for ATC types (blades) are for safe continuous current. I am working on an easy way to adapt atc fuses into the block.....watch this space.
 

jp928

Well-Known Member
How about this try? 1/4" brass tube (K&S #8131, hobby shop), Keystone 3557-2 fuse holder.


The brass tube, with some tinning, is a very firm fit in the clips. The 1/2"pieces of tube are joined here with a bit of 5mm balsa, with superglue. Something harder like spruce dowel would be better, but dont have any to hand. The fue holder will also accept the low profile ATC type fuse. There is enough room to slightly rotate the assembly, in case there is a concern about corrosion. I made the overall length 1.25", but the clips measure a real 1-5/16", so next one will be a bit longer. Soldering the fuse holder to the brass is a little tedious - a fuse holder with longer tags would be easier - if you can find such a thing, please report its number and source. Next ATC fuses I get will be LED types - LED lights up when the fuse is blown.
 

cobraboy

Well-Known Member
A fuse made of wood ! Interesting.
If I may be so bold - not one of your better ideas. Plus you still have the root of the problem present, the crap fusebox.
I had to check the date to make sure it wasn't April 1st :hmm:
 

jp928

Well-Known Member
Bit snarky! The FUSE is not wood, just part of the Fuse Adaptor. If I had a suitable piece of ceramic or synthetic material I would have used that as the insulator between the two adaptor ends. I felt the two pieces of brass needed to be supported so that inserting the unit into the clips would not put stress on the solder joints. To my mind the fusebox is only crappy when there is too much heat generated at the connections, caused by poor connections, caused by the poor design of those clips that are not well connected to each other. So, yes , the poor design makes the fuse block crappy! Part of the force required to insert the adaptor is probably caused by the wire clips I made, which some have sneered at.
In the 928, where the big fuse and relay board is in the passenger footwell, what do you think Porsche covered the electrics with? Something non-conducting - a panel of 15mm ply, ~ 18" x 12". Its not going to short anything out, no matter how hard the passenger pushes on it. My blade fuse adaptors there have lasted some 10 years now, with only one failure due to a dry solder joint, and no overheated connections. The original idea for these blade adaptors was to get rid of the continental bullet fuses because the top copper connectors overheated , due to a combination of small contact area and losing tension. When my last fuel pump relay failure occurred , and I jumpered the relay I actually saw a spark at the top fuse connection, which testifies to the poor quality of the connection.
 

mrtask

Well-Known Member
The lid won't fit on the fusebox any more, unless you modify it with, mmm, maybe some more balsa. !?!?
I'm with cobraboy on this one, JP! I think there has to be a safer solution to our melting fusebox woes that doesn't involve additional kindling.
I don't want to cause any offence, but I don't want to hear that you had to grab your fire extinguisher either.
 

jp928

Well-Known Member
Would your objections disappear if I used a piece of plastic instead of balsa? A piece of rubber vacuum tubing - thick wall stuff? Is that the only negative you see?
Not really concerned about the lid not fitting.
 

cobraboy

Well-Known Member
Bit snarky! The FUSE is not wood, just part of the Fuse Adaptor. If I had a suitable piece of ceramic or synthetic material I would have used that as the insulator between the two adaptor ends. I felt the two pieces of brass needed to be supported so that inserting the unit into the clips would not put stress on the solder joints. To my mind the fusebox is only crappy when there is too much heat generated at the connections, caused by poor connections, caused by the poor design of those clips that are not well connected to each other. So, yes , the poor design makes the fuse block crappy! Part of the force required to insert the adaptor is probably caused by the wire clips I made, which some have sneered at.
In the 928, where the big fuse and relay board is in the passenger footwell, what do you think Porsche covered the electrics with? Something non-conducting - a panel of 15mm ply, ~ 18" x 12". Its not going to short anything out, no matter how hard the passenger pushes on it. My blade fuse adaptors there have lasted some 10 years now, with only one failure due to a dry solder joint, and no overheated connections. The original idea for these blade adaptors was to get rid of the continental bullet fuses because the top copper connectors overheated , due to a combination of small contact area and losing tension. When my last fuel pump relay failure occurred , and I jumpered the relay I actually saw a spark at the top fuse connection, which testifies to the poor quality of the connection.
The new fuse adaptor being made of non flamable material will remove one hazard.
The new fuse adaptor has four contact points to cause issues instead of two. The contacts into the OEM fusebox, and the contacts for the blade fuse, yes blade fuses corrode as well.
The adaptor having solder runs on the area that will contact the OEM fusebox clips will mean there are high spots giving limited contact with the clip and these will heat up more than an OEM glass fuse.
As stated by Mr Task, the fuses will be vulnerable stcking out so far.
It is not an elegant solution, therefore it is not the right solution.
If it were my fusebox that had melted and needed changing I would track fown a NOS fusebox with harness, change it all out, fit new fuses with clips, and fit relays to the headlights, and spray the finished box with electrical inhibitor.
FWIW when I became aware of the fusebox issue I removed all my miss sized fuses, carefully cleaned all the contact clips, supported them with needle nose pliers and tightened them all up, inspected the wiring at the rear of the box for heated joins, fitted new correct length fuses, and inhibited the box.
The fuses were gripped really tightly and I never worried about it again.
You could always fit one if these in the knee bin… https://www.toolstation.com/fireangel-10-year-battery-smoke-alarm/p52932?store=OJ&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=_dm&pcrid=558702669986&pkw=&pmt=&gclid=CjwKCAiA4KaRBhBdEiwAZi1zzhYPPd6jtn_uu_OsKg1g0gw1kV4UsG35VbzgymmYXp_LCZYykfzqnxoCM6QQAvD_BwE&gclsrc=aw.ds
Ooops sorry I can’t help myself
 

harveyp6

Well-Known Member
They are a nice looking thing, but they still don't get around the original problem which is the clips in the fusebox not gripping the fuse tightly enough.
 
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