I saw an article on one of the kit builder sites which showed a secure way of passing wiring looms through the firewall. this was a combination of a fire-resistant grommet and several metal plates. Anyone recall this and if so can you point me in the right direction. Thanks
Not sure which it might be, but these guys had a video on the general subject of firewall penetrations... https://www.youtube.com/watch?v=Rs4ohdgulpE
Probably not what you are thinking of, but I have made pass-throughs similar to these: http://www.aircraftspruce.com/catalog/elpages/firewall_penetration_kit.php?clickkey=23949 Mine are longer, to go through a composite bulkhead/firewall. The fire sleeve slips over the wiring and over the penetration tube. It is filled with fire stop caulk, then closed around the wiring with a hose clamp. BJC
I would recommend Teflon covered wire. It will burn if held in a flame, but the fire will not travel along the wire like PVC. Also will not melt like PVC if the wire gets hot from a short. Also much more abrasion resistant, for high vibration areas (although it is good practice to secure it firmly).
THe only thing with those firewall pass trhoughs is that the ends should be flared out so that cables can't rub on the edge. If the covering on the main power cables is chaffed through it can spark erode its way though the structure without blowing the fuses.