Is this sketchy wiring setup the reason my garage breaker keeps tripping?

That setup is a classic bootleg grounding hack, usually done by someone trying to run modern 3-prong power tools on an old 2-slot ungrounded circuit. The green wire is meant to provide a path to ground, but shoving it directly into the slots or wrapping it around frayed cords is exactly how garage fires start. It’s a total mess of a connection that should never have been made.

The reason your breaker keeps popping is almost certainly high resistance or intermittent shorting at that specific connection. Power tools like table saws or compressors pull a huge amount of current the second you flip the switch. If that connection is loose—and it definitely is if it's just held together with electrical tape and shoved into slots—it’s going to arc and overheat instantly. The breaker is actually doing its job by cutting power before those rafters catch spark.

Kill the main power at the panel immediately and rip all of that out. Don't even bother trying to save that extension cord or the outlet. Once the power is off, check the back of the box to see if there's actually a ground wire available. If it's old two-wire cable with no ground, you can't just put a standard 3-prong outlet in there and expect it to be safe. The standard fix for this in an old garage is to install a **GFCI receptacle** at the first outlet in the run. A GFCI provides shock protection even without a ground wire. You just label the outlet "No Equipment Ground" and it stays within code. It’s a much more reliable way to handle old wiring than whatever hack job was previously installed. Get a simple plug-in circuit tester once you've replaced it to make sure your new connections are solid.

Man, I've seen some sketchy DIY but that sounds like a legit house fire waiting to happen. If the previous guy was hackin' stuff like that togather, you'd better check every single junction box in that garage. I'd bet money there's more "creative" wiring hidden elsewhere. Don't just fix that one spot. Grab a non-contact voltage tester and poke around. If he did that to a ground, who knows what else is crossed or double-tapped back at the panel. You're lucky you haven't been zapped trough your saw's metal casing yet.

Totally agree on the GFCI fix, but one thing to watch for when you're ripping that junk out is the condition of the actual house wires feeding that mess. If that hack job has been arcing and overheating like the other guy mentioned, the insulation on the wires coming from the panel might be brittle or charred several inches back.

Make sure you trim the wire back untill you see fresh, flexible insulation. If you just hook up a new outlet to heat-damaged copper, the insulation will just crumble off the first time you shove the outlet back into the box, and you'll have a direct short inside the wall.

That fire hazard needs to go right now. Since you're running heavy power tools, you need a GFCI that can acutally handle the motor surge without nuisance tripping. I always swap those old garage outlets out for the Leviton SmartlockPro Slim GFCI. They are built way better than the generic store brands and the slim profile makes them way easier to jam into those old, cramped garage boxes once you've cleaned up that bird's nest. While you're at it, grab a pack of Ideal Wing-Nut wire connectors to make sure your new splices actually stay tight this time. Don't risk it with cheap tape again.

Quick update—I killed the power and started peeling back that tape. Like one of you mentioned, the insulation underneath is incredibly brittle and basicly crumbled in my hand. I’m definitely going to grab those Leviton GFCIs, but I also found another "creative" junction box behind some plywood. If the wires are this crispy, do I need to pull new lines all the way to the panel?