I think it's a deposit from the 'smoke' rising from the burning / decomposing plastic of the breakers. Because of the electrostatic attraction, airborne particles sometimes deposit preferentially on cables and live parts. It's most noticeable on HV DC: the EHT lead to the tube in a TV would get covered in fluff over time.
I think it's cockroach powder...or some kinda insecitcide that the Rentakill idiots insist on spraying all over DB's and control panels. Bend one of the wires over and see if it's on the back as well, if it's only on the front then I'll bet you it's the roachman.
I think it's a deposit from the 'smoke' rising from the burning / decomposing plastic of the breakers. Because of the electrostatic attraction, airborne particles sometimes deposit preferentially on cables and live parts. It's most noticeable on HV DC: the EHT lead to the tube in a TV would get covered in fluff over time.
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc