I ve added an extra fuse box with 6 extra fused spade type connectors, I bought the box at my local auto parts store. This idea was suggested by members of this site to accommodate the electric choke, MSD distributer, power seats and dual electric fans along with an upgraded alternator. I was told to use 10 g wire from the "IGN" tab on the original fuse box to the extra fuse box. My question is, should I use an in-line fuse between the new fuse box and the original box ? The new fuse box has individual fuses for each connection. My vehicle is a 65 chevelle, 327, auto, with the above listed components. Thanks in advance.

I would run a new line from the battery with either some type of fuse or fusible link(use the fuse/fusible link within the first 12 inches of the battery or supply source), and integrate a relay or starter type solenoid as a switching mechanism. Use the ignition or accessory spade on the original fuse box as the switching wire to power up the new fuse box, depending on when you want it to turn on and off.....that way, the load is not tapped/piggy backed onto your original wiring or original main fuse box, and it is independent of everything else. If something goes wrong on the new wiring, you can trace it to just those applications, or new main fuse/fusible link and you don't risk blowing the fusible link on the load side of the horn relay. Honestly, I would oversize the supply wire to the new fuse box to like a #8, that way if you want to add another fuse box later, you have the capacity without having to run another power wire to the new 2nd fuse box. If you're going with a fusible link, the proper procedure is to go down 4 numbers i.e. 10 gauge wire use 14 gauge fusible link, etc. Relays are a great way to switch power without having to run the main power wires in and out of switches, and relieve the load off your main fuse box.....headlight relays are a good example since these old cars usually have dim headlights from the voltage drop when the power finally gets to the lamps. PM me if you have any questions, I'm an electrician and I've done a ton of stuff on my car with the electrical....good luck, and remember to connect the wire to the battery AFTER all connections are made:thumbsup:

When you say hook it up to the battery, does this mean the battery junction box ?? Also, the fan already has relays, I bought a kit that included them. Thanks for your time and the quick reply.

You should hook it directly to the battery. The IGN plug is not likely wired to handle the load of the entire new fuse block. If, for instance, the IGN clip is wired internally with a number 12 wire, the #10 from the new fuse block does you no good at all because the #12 will always be the smallest wire and may be incapabile of carrying the load. Get an inline fuse with a total capacity of 20% more than the total load the new block will carry and tie it to the battery. If you tie it to the IGN slot, make sure you check the wire size to that position and do not exceed the max current rating for that position.

Chuck

It really should be connected to the horn relay, assuming the alternator output also connects there as it did originally. If connected directly to the battery the current flow, engine running, will be from the alternator to the horn relay, to the battery through the fusible link, from the battery to the new fuse block. This adds 6-8 feet of wire/resistance, plus the fusible link, to the circuit. If there is a constant load added to the new fuseblock it will have the effect of reducing the battery charge voltage.

The horn relay is the power distribution point. I would connect the #10 wire w/fusible link there.

If your car has the alternator output connected directly to the battery then the best choice is the battery.

It really should be connected to the horn relay, assuming the alternator output also connects there as it did originally. If connected directly to the battery the current flow, engine running, will be from the alternator to the horn relay, to the battery through the fusible link, from the battery to the new fuse block. This adds 6-8 feet of wire/resistance, plus the fusible link, to the circuit. If there is a constant load added to the new fuseblock it will have the effect of reducing the battery charge voltage.

The horn relay is the power distribution point. I would connect the #10 wire w/fusible link there.

If your car has the alternator output connected directly to the battery then the best choice is the battery.

If done this way won't the items added via the distribution block be "on" all the time? Shouldn't these come on with the ignition and if so how would you accomplish this using the horn relay as power? TIA Pete

I second the horn relay tap for auxiliary power. When running system power comes from the alternator and NOT the battery. So optimize around the alternator power supply to use the shortest wires.

Do NOT tap into the fuse block for significant loads, and ANY electric fan is a significant load. The original power supply wire to the fuse block is barely adequate for what is there. Add another load and things get ugly.

There are a couple of ways to make things ignition hot rather than battery hot.

One way is to make the power supply ignition hot by using a relay controlled from the fuse box ign terminal to power up/down the entire auxiliary fuse panel. A relay control is a minimal amount of power and can thus be added to the original fuse box. The downside of this approach is that you may need a pretty large relay to handle all the power. The Painless Performance CirKit products use this approach.

Another way is to use a battery hot power supply to the auxiliary fuse panel and ignition-hot controlled relays for individual loads. This works well with larger loads like electric fans.

My approach was to install a modern power distribution box up in the front DS corner. All the Maxi 30A-60A fuses I could ever use, and a bunch of relays to boot. All in one nice clean box. I use the seperate relays powered from battery hot and controlled by whichever I want.