New Fuse Box Questions

[matthon]

Ammeter eliminated, headlight relay kit installed, have MSD ready to run, rewiring a few other items, adding 60 amp Denso alternator, other modifications - thought there had to be a better way to deal with the ammeter, fusible links, fuse box.
My fuse box has 5 fuses (dash lights/hazard, stop light switch, & interior lights/lighter/heater/radio).
I have a Painless 70207 fuse block, 7 circuits (3 Constant, 4 Ignition), 20amp fuses, circuit breaker included.
Removed old fuse box, mounted Painless in same spot, fits perfect.

I decided to eliminate the old ammeter wiring with the welded splice entirely by just bypassing it.
· New charge wire from Alternator goes directly to Starter Relay
· Bought a junction block
o Ran both the 'run' and 'start' wires to it
o Wire to the coil
o Wire to a voltmeter
o Distributor connected to coil
· 3 Constant
o Wire directly to light switch (B1, replaces BLK-TR)
o Wire directly to ignition switch (replaces RED wire)
o Wire to pink/pink splice where fuse box was (hazard relay/stop light switch/light switch for interior lights).
· 4 Ignition
o Wire directly to aftermarket radio (will use original ORANGE wire to radio for lights for Tach/Accessory Gauges, radio has fused constant power from battery)
o Wire directly to heater switch (BLACK-TR)
o Wire directly to new alternator
o Last circuit will run the aftermarket tach (and possibly the lighter, although I have never used it to even charge a phone).
· When running wires directly to original plastic connectors, used terminals that fit and lock in

That leaves 3 wires where the old fuse box was:
· BLACK – this comes from the ignition, goes to a welded splice, then out to the Flasher, Gauges, and fuse box.
· TAN and ORANGE – the TAN is the feed from the Light Switch, the ORANGE is power to the Instrument Lights.

Questions:
The BLACK from the ignition is a larger gauge wire than the Pink Relay wire from the Painless. The Painless instructions want you to tap into an ignition power source at the fuse box on the hot side of a fuse. Taping in to the hot side and splicing seems to be the same in concept, and my understanding is the Painless Relay is drawing less current than the BLACK wire can carry.
Even though these are different gauges, can I safely splice these wires together?
Or would it be better to connect the Painless Relay to the junction block I added?
(I can always splice this black to the lighter wire)

TAN and ORANGE – I upgraded my instrument circuit boards and lights, and the fuse for them was actually 10amp (I think the fuse box has 5 on it). I was going to buy an inline fuse holder, put a 10amp in and splice it together, and zip tie it to the side of the Painless.
Since the Light Switch is now fused, is this additional fuse needed?

Alternator charge wire - using 8-gauge wire with a 12-gauge fusible link.
How do you determine the length of the fusible link?
Is there a comparable in-line fuse that would work, not sure the size of fuse to use?

Headlight Relay Kit – the relays and fuses are under the battery, and there are 2 power wires routed across the firewall to the Alternator charge stud.
Is there a reason for getting power from the alternator, or would any 12-volt source work without issues?

 

[BillGrissom]

The black wire is thicker than Painless' pink wire yet you are worried the black can carry less current? Try editing.
2 series fuses aren't needed, but wouldn't hurt.
I would used an in-line fuse since more accurate and easier to replace. I think I have seen them up to ~80 A at auto parts. Fusible links were a cheapie factory design to avoid catastrophies. Some cars have a fuse built into the BATT+ connector, so there might be retrofits. That would protect for most things, but might also want one on the ALT+ output wire.

Any 12 V source would work. Why not BATT+ which is just above your relays? Much easier and safer than the circuitous route aft to the firewall then fwd again. The only disadvantage is that if tapping BATT+, the current used won't be measured on your dash ammeter, if still using that. Indeed, no under-hood loads are measured in the factory design, but they are all transient - horn, starter, ...

 

[matthon]

Not worried the black wire can carry less current. My understanding is the pink is drawing less than the black is capable of, it's not like the black is pushing current, the fuse box is drawing, which s/b ok, the opposite would be an issue.