PDM / Tefzel Wire AWG

I am working on wiring my boat with a Moristech P30 PDM (tefzel wire) and had a question in regards to wire AWG for some of my 20amp outputs. In the documentation for the PDM it suggests using 14-16AWG wire for the 20amp outputs where some of the documentation for my trim pumps call for 10 gauge wire with a 20amp fuse. The plan was to just wire up with 14AWG this weekend and verify but figured I would post up here to see what the community thought. Is it a general practice to size down wire when running tefzel vs txl ?

Thanks,

Nick

The main limiting factor in how much current a given wire size will carry is the melting point of the insulation. Some PVC insulation will melt around 100°C whereas Tefel doesn't melt until around 300°C. Of course there is ambient temp and voltage drop across the wire to consider as well. For example a 14AWG wire in the cabin at 30°C will be able to carry more current than a 14AWG wire in the engine bay that is already 100°C before it has any current going through it.

So to answer your question - yes you can generally use a smaller conductor if you have higher temp insulation material such as Tefzel Vs PVC. I would generally be happy to use 14AWG tefzel for most 20-25A applications.

Awesome, thank you for this response !