Pilot reported electrical systems failure with smoke and fumes present in cruise and diverted to make a precautionary landing.

Narrative

At XA:12 (local) on DATE; I departed ZZZ in Aircraft X (Cessna 414) in route to ZZZ1 on an IFR flight plan with a planned cruising altitude of 17;000 feet. I was the Pilot in Command (PIC) and the pilot flying (PF). I had a fellow pilot sitting in the copilot seat performing radio; checklist and pilot monitoring (PM) assistance. We both possess an Airline Transport Pilot (ATP) certificate and we both fly for Part 121 airlines. During vectors around multiple storm cells; we established a stable climb profile out of ZZZ. The aircraft's cabin was hot and stuffy so I turned on the electrically operated air conditioning (AC) unit which caused a significant draw on the electrical system. I also had the anti-collision; position and instrument panel lights on that are required for night navigation along with a BFG Stormscope unit; a communications/navigation radio; a Garmin 430 GPS unit; a DME unit and a transponder unit. Climbing through 10;000 feet; I turned on the Pitot Heat anticipating a freezing temperature at 17;000 feet. At this point in the flight; the electrical system was operating near maximum capacity. Climbing through 15;500 feet; my 6-pack instrument panel lights all went out at the same time without any circuit breaker tripping. About 30 seconds later; the PM and I both smelled what we concurred to be burning wire fumes. Although we did not see smoke or fire; we declared a 'PAN PAN PAN' with ZZZ2 departure control and diverted to ZZZ2. The controllers at ZZZ2 re-designated our aircraft as a priority aircraft and committed Crash; Fire; Rescue (CFR) and police resources to our landing. During the descent; we turned off the AC and Pitot Heat and noticed that the burning fumes smell was gone. We landed on Runway XXR at ZZZ2 without any problem.