Firewall penetration -7-

[Simon Hitchen]

Could anyone give me a little guidance please as to the best location to pass the wires through the firewall. I'm not referring to the sensor pack for the Dynon but more specifically the large 6wg wire from the master relay to the main bus, the 20 AWG master relay coil wire, the starter selenoid wire, alternator f-line, and magneto p-leads. Are most people bundling these wires together with one firewall bulkhead fitting?

Many thanks,

Simon.

 

[JonJay]

Upper left and upper right sides of the firewall are good locations to run things like p-leads, sensor wires, ems, etc.... There is usually not a lot going on there. For the power wiring, the shorter you can make those runs to your main buss the better. The tunnel in the 7 makes a great spot to run the power or along side the angle next to the tunnel (the vertical part of the tunnel, channel, whatever you want to call it). I also ran my master coil wire along with the Batt power. It is not a great location for a lot of wires though due to fuel lines taking up some of that space.
There is a huge amount of builder variance here. Use your best judgment. Keep wire runs as short as possible. You can bundle many things and reduce your firewall penetrations, but keep in mind down the road service and modifications. You will modify your wiring at some point. That is an almost guarantee.

 

[rzbill]

I think you will find as many answers to this as there are VAF members.

But to try to help with your thoughts.

I have 3 electrical penetrations. Two are up high adjacent to the upper engine mount locations. One is down low near the solenoids under the battery.

Penetrating near the engine mount gives structure for supporting the wires both on the engine side and on the cabin side of the firewall.

I used the upper penetrations for sensors, mags and battery bus.

The lower one was for Main Bus feed, regulator and solenoid control.

There are other ways that are just as valid.

 

[Simon Hitchen]

Thanks guys, I guess more specifically, I've installed the master relay and starter selenoid as per vans plans under the odyssey battery. Just wondered where most people are running the main wire from the master relay to the electrical system. In my case 6 AWG wire to the main fuse block on the sub panel. Is there enough room to route the wire between the master relay and F-7127b vertical channel. It may require a fairly sharp radius on the 6 AWG wire.

Thanks

 

[sf3543]

For passing larger wires through the firewall, I prefer to use a passthrough lug. You can just bolt the wire on each side of the firewall. Additionally, there is no hole to seal.
Look at the following link for an example.

http://motorsportswiring.com/marine...ost-p-2.html?zenid=l01co6q46t1qv4p0utdjmjkd76

You can also make your own using some Deleon or other nonconductive material and a threaded rod, nuts, washes, etc.
Good luck

 

[rv7charlie]

Thanks guys, I guess more specifically, I've installed the master relay and starter selenoid as per vans plans under the odyssey battery. Just wondered where most people are running the main wire from the master relay to the electrical system. In my case 6 AWG wire to the main fuse block on the sub panel. Is there enough room to route the wire between the master relay and F-7127b vertical channel. It may require a fairly sharp radius on the 6 AWG wire.

Thanks

Late to the party, but...
Battery on engine side of firewall, right? How much current in the cockpit? You could almost certainly downsize the wire (a lot).

Charlie