I am contemplating the design of a printed circuit board to be used as a heating element. No components will be mounted to the board. I would just use a long squiggly trace as a heater. The trace would be terminated at each end of the board with a large solder pad. A wire will be soldered to these solder pads. The heater will operate up to400VDC.
What precautions must I take in trace spacing to avoid electrical arcing? The heating element will not be exposed directly to air. It will be bare copper that is nickel plated (no solder mask) sandwiched between a sheet of thermal transfer material and an aluminum block.
How about other nasties such as excessive leakage current?
I plan on using FR-4 board material for this experiment. Do you see any problems with this?
Could solder fluxes or other residues pose a problem?
I'm asking up front. It's better to be safe than sorry.