Did you have the garage and compressor rewired?
I’m also curious about how your project is going.
I didn't forget about you guys, just didn't have an update (or the time to even log in) until today. Here's what has taken place so far, and everything is still in progress:
1. The shop breaker boxes have been replaced with the one I linked. It is not yet complete (meaning I haven't divided the circuits the way I want them yet), but it is operable and the shop has power. The box was just ripped out, all of the "hots" "neutrals" and "grounds" were identified, then placed on their own circuit in the new box (meaning goodbye double-taps). The old boxes had a 2-pole 40A, a 2-pole 30A, and 3 single-pole 20A breakers. That was it. The new one, without any divided circuits or modifications now has 7 single-pole 20A breakers, a 2-pole 30A breaker for the compressor, and a 2-pole 40A breaker. That just shows how horribly overloaded the old boxes were.
2. After that, a single 110 outlet was installed at/for the furnace (blower). That also received it's own breaker. Now we're at 8 20A breakers.
3. The compressor was worked over. It started with mounting the starter box higher, installing the proper connectors, and (most importantly) properly grounding it. Upon running it, an amp clamp revealed it was drawing about 24-24.5 amps while running (which is exactly what I guessed in an earlier post - I like it when I don't know what I'm talking about, but end up correct after some coaching. Thanks everyone!). The first check at that point was the capacitor. The old one was in such bad shape it wasn't legible and was really swollen and warped. The best guess on the text was "80." It was an oval-shaped cylinder. He grabbed a new 80 microfarad capacitor (circle-shaped cylinder), installed it, and ran it. The load reduced from 24-24.5 to 20-21 amps. The lights still surge, but my eyes tell me the new capacitor reduced the surge by about 75%. Dramatically better. This is where we stopped, but more work is still being done.
The new box and all of the wiring within looks SO darn good. No more rat nest.
The plan is to remove the 4-4 cable that runs between the pole and shop. The 4AWG cable that supplies the shop breaker box is also going to be removed. 2AWG will replace it, and a 100A breaker will go on the main/pole breaker box to compliment the new 100A main in the shop breaker box. Instead of hanging a cable, the plan is to bury it between the pole and the shop. We'll bury it to the closest corner of the building, then run it up to the roofline on the wall, over the doorway, then down to the breaker box (all on the outside in some sort of conduit/shielding). This is necessary due to the large concrete pad being in the way.
I'll post pictures when the work is complete, and update as time allows. Thank you all for your advice!