Thoughts on mysterious pink grit inside a new Eaton panel?

I ran into somethig almost identical when we did the sub-panel in our garage using a Siemens load center. I found a pile of that same salmon-colored grit near the ground bar about four months after the inspection. It turned out to be a mix of two things: tiny shavings from the copper bus bars during the initial breaker installation and some red masonry dust from the brickwork they drilled through for the conduit. The pink color ussually comes from that specific shade of red drywall mud or even fire-rated sealant that some guys use to plug the holes where the Romex enters the top of the box. If your panel is on an exterior-facing wall, temperature swings can make that stuff get brittle and shed over time. Since you aren't smelling anything metallic or ozone-like, I whould bet it is just construction debris that finally migrated down. I usually just hit the bottom of the can with a shop vac—using a plastic nozzle to stay safe—and see if it comes back. If the pile stays gone, you are probably just looking at leftover mess from the install day.

I honestly don't think you're looking at metal shavings or brick dust here. If it were from the initial install, you would have noticed it the day the electrician finished up, not half a year later. To me, that specific pinkish-orange grit sounds exactly like dried-out fire-stop sealant. When we did the renovation on our 1960s ranch, the contractor used a 3M Fire Barrier caulk around the service entrance cables. Within a few months, we started finding this salmon-colored sand at the bottom of our Square D panel. Because the panel was located right near the garage entry, the constant temperature swings and air draw through the wall caused the sealant to get brittle and flake off every time the house settled. Check the knockouts at the top of your panel where the Romex or conduit enters. If you see a bright orange or reddish gunk packed around the wires, that is almost certainly the culprit. If it crumbles when touched, it’s just the product failing to stay flexible. It’s harmless to the breakers, though it looks alarming. I just vacuumed mine out with a small shop vac and didn't worry about it further.

Check the top of the enclosure where the service entrance cable enters. If the installer used Gardner Bender DS-110 duct seal, that stuff can get brittle and flake orange-pink grit if it wasn't kneaded properly. However, if you're running an Eaton BR or Square D Homeline, look at the bus bar stabs. I’ve seen factory dielectric grease oxidize into a salmon-colored crust when exposed to certain humidity levels or trim cleaners. Grab a flashlight and check if the grit is concentrated under the breakers. If it’s the lube reacting, you’ll see it crystallizing right on the bus.

I totally agree with the grease theory, but you shold also check the conduit fittings. If the guys used alot of orange CPVC cement or that pinkish primer on the pipes leading into the panel, it can drip inside. Once that stuff fully cures and the house settles, those little drips get brittle and shatter into that wierd gritty dust. It looks exactly like chemical residue becasue it basicly is. Take a flashlight and look at the very top of the box where the pipes come in to see if there are any dried 'icicles' of glue hanging there that might be flaking off.