69Stanger408 82 Report post Posted April 20, 2020 To all, The following is in reference to electrical distribution of my 69 Mach One, which I adopted from VicFreg. Much time and effort was put into carefully installing my electrical system but as you can see a failure of materials could be catastrophic. Wanted to drop you a note and thank you. As you may recall, I copied your electrical lay out with the battery / solenoid in the trunk, on/off switch, fuse protection and two distributions (one behind AC in passenger compartment and one in engine bay). Yesterday I was test driving the car and the entire electrical shut down. All dead. I got the car home and started to trouble shoot via a meter. Sure enough, the 175Amp fuse on the battery board blew. So I started to ohm out each wire on the distribution block to see which one was connected to ground (which caused the fuse to blow) because the main wire distribution wire actually ohm'd to ground. First wire I disconnected and tested was the alternator (as this block was much easier to access, and the alternator was the top connection). Once the alternator wire was removed the system no longer had conductivity to ground. Now I know somewhere along that wire ground contact is being made. The wire appeared good, no abrasions, visible, the wire is also in a wire sleeve by itself. The wire lug connections appeared to to be good, had no Idea why the the power post from alternator would be touching ground. Further inspection showed a burn mark on the hold down bolt. Thought maybe the post arched to ground. As I was rotating the wire to reattach to the post, I flipped it over and noticed a small split in the heat-shrink that actually made contact with the alternator housing, that was the culprit. I put another sleeve of heat shrink over it followed by electrical tape. Reassembled and all is well. I want to thank you for the protection suggestion of the 175Amp fuse. This would of been much worse if the fuse was not there. A $5 dollar fuse saved a very expensive project. I'm still in a bit of a stress breakdown as I continually think of the what may have happened if I did not follow you suggestions. 2 capemustang and RPM reacted to this Quote Share this post Link to post Share on other sites
Rich Ackermann 174 Report post Posted April 20, 2020 Glad to hear that there was no major damage and that you found the culprit. After hearing this, I am going to install a 175amp fuse on my battery. 1 RPM reacted to this Quote Share this post Link to post Share on other sites
stangman69 17 Report post Posted April 20, 2020 Just so I understand your routing, since I'm about to embark on this same project myself and have also poured over @Vicfreg and @Mike65 build threads in re tucking the wiring harnesses and AAW... You have a wire running from alternator charge post in to a distribution block in the car somewhere and then from there back through a 175 fuse to the battery itself? Assuming yes, wouldn't it be prudent to fuse the alternator charge line itself to further isolate that particular component in the event of a problem? In addition, of course to fusing any line coming off the battery? Starter would be isolated via the solenoid and not fused (although I've heard of folks fusing the battery to starter line with a large amp fuse with success). Nate Quote Share this post Link to post Share on other sites
69Stanger408 82 Report post Posted April 20, 2020 44 minutes ago, stangman69 said: Just so I understand your routing, since I'm about to embark on this same project myself and have also poured over @Vicfreg and @Mike65 build threads in re tucking the wiring harnesses and AAW... You have a wire running from alternator charge post in to a distribution block in the car somewhere and then from there back through a 175 fuse to the battery itself? Assuming yes, wouldn't it be prudent to fuse the alternator charge line itself to further isolate that particular component in the event of a problem? In addition, of course to fusing any line coming off the battery? Starter would be isolated via the solenoid and not fused (although I've heard of folks fusing the battery to starter line with a large amp fuse with success). Nate Agree on the starter fuse, may add one as the situation can be be duplicated there as well. The starter line is a direct connect from trunk mounted solenoid to starter, installing a fuse may be a wise choice. Everything on the distro blocks is fuse protected, believe that is why nothing major happened, other than replace the head distribution fuse and re-do a heat shrink tube. I did not put an in-line fuse on charging line other than the mega fuse, of course it all runs through the distribution system so it is protected. No other fuses blew, and when I replaced the fuse and heat shrink everything was back to normal. If I'm missing something (anyone) please advise. This has me questioning myself. Two things that always worry me about restorations is fuel and electric. Everything I did is brand new from the wiring to the fuel. Quote Share this post Link to post Share on other sites
1969_Mach1 333 Report post Posted April 20, 2020 You are fortunate a 175 amp fuse failed before any thing burned. I agree, the charge wire from the alternator should have a fairly direct route to the battery. Somehow fusing it would be wise as well. Quote Share this post Link to post Share on other sites
stangman69 17 Report post Posted April 21, 2020 On 4/20/2020 at 12:15 PM, 69Stanger408 said: Agree on the starter fuse, may add one as the situation can be be duplicated there as well. The starter line is a direct connect from trunk mounted solenoid to starter, installing a fuse may be a wise choice. Everything on the distro blocks is fuse protected, believe that is why nothing major happened, other than replace the head distribution fuse and re-do a heat shrink tube. I did not put an in-line fuse on charging line other than the mega fuse, of course it all runs through the distribution system so it is protected. No other fuses blew, and when I replaced the fuse and heat shrink everything was back to normal. If I'm missing something (anyone) please advise. This has me questioning myself. Two things that always worry me about restorations is fuel and electric. Everything I did is brand new from the wiring to the fuel. Did you use a good quality charging wire and solid crimps and quality heat shrink? Just curious and wondering...with you I'm sure...why that point failed. nate Quote Share this post Link to post Share on other sites
69Stanger408 82 Report post Posted April 22, 2020 High quality, 100% copper, with top shelf ends and heat shrink. No corners cut in this car, that's thing about it. No matter how much time, patience, and quality work you put into it, things can go arise which are out of your control. The fact that the fuse did what it was supposed to is take away. Adding an additional one on the alt feed to the power distro to isolate the even further. The more the merrier 1 stangman69 reacted to this Quote Share this post Link to post Share on other sites
Vicfreg 771 Report post Posted April 22, 2020 Wow! Good detective work. And thank goodness for these new midi-fuses. I think my alternator wire heads straight away from the alternator body, I am going to check that myself. If you try and fuse the starter, it will likely blow, due to the current draw. That is why I put my starter solenoid in the trunk. The starter wire is only hot when you are cranking. In the original installation, the battery hot goes directly to the starter solenoid, so it's no different. Some of the old GM cars I had with the starter mounted solenoid had a fusible link to protect the main battery feed. I have midi type fuses on all my main power feeds. Quote Share this post Link to post Share on other sites
