I installed the firewall main wiring loom pass through today, The wires were first wrapped with firesleeve that also passes through the firewall and then the whole thing is again wrapped in firesleeve, stainless steel tie wraps secure it all and I then wrapped it in self sealing silicone tape that I admit does not look the best but hopefully will prove practical. The firewall blanket was also completed by re-installing the piece that covers the pass through.
