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Originally Posted by jay_bob
In fact I am getting ideas about rebuilding the entire fuse box with ATC holders in this way. You could strip out the existing clips and leave only the terminals on the back. Then using ring tonge crimps, attach the pigtails from the ATC fuse holders to the appropriate terminals in the back. Then use potting compound to hold the ATC fuse holders in position.
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You can get ATC fuse holders in a block, some are stackable for length. Look at a truck body building supply web site or a company like Painless wiring.
Quote:
Originally Posted by jay_bob
You are right about the blower fuse, I will do no more than a 15 A ATC. I looked at the FSM wiring and the blower is fed from a 2.5 mm2 wire which is approximate to a 12 AWG. In my world that is a max 20 A fuse. However they also feed the a/c thermostat control and clutch relay and recirc flap actuator off a 0.75 mm2 wire which is approximiately #18 AWG which we cannot fuse at more than 7 A. (UL508a)
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For proper fusing, the max load plus some % would be more proper than wire size. A clamp on amp meter is very helpful here,make sure it will read DC , the less expensive ones only read AC. ( Tenma
www.mcmelectronics.com/manufacturer/TENMA/01001018 is a decent house brand , Extech is great
www.extech.com , Fluke is high end.
Fuse curve matters too. Take a look at Digikey , MCM , ( Farnell for the Brits on this list ) or similar for fuse data sheets. You will see a fuse can carry more that it's rating for X amount of time. As a side note, 60's - 70"s Brit cars used fuses of a different rating and installing a USA rated fuse will cause a melt down if the circuit is overloaded.
Quote:
Originally Posted by jay_bob
I am seriously considering installing a fuse in the 6 mm2 line from the starter to the light switch. Way too scary for my taste to have unprotected power from a Group 85 battery running through the dash. Just have to calculate a size that would never trip under normal circumstances but blow in the case of a catastrophic short under the dash. I'm thinking in the 80 to 100 A range.
Unfortunately the regulator circuit for the alternator depends on this path, if the fuse were to open up you would lose regulation on the alternator. Although in that case you have isolated everything but the battery so you would not be operating in an overvoltage condition for very long as you would have no electrical system operating at all. 
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On my 70's International backhoe ( For German content, it has a D239 Nuess engine and Bosch VA injection pump. ) I added fusable links to the main feed from the battery to dash, seperated the alternator output from the main wiring / added a fusable link and added 4 push circuit breakers for lighting.
You could run a fresh wire from the alternator output to battery and add a fusable link/ fuse along the way. A fuse should be as close to the powersource as possible. Consider the battery the power source.