#4 wire is routed to the instrument panel. Now What?

[AMURRAY]

The #4 wire from the battery solenoid is routed to the instrument. The circuit breakers for the battery bus are daisy chained together. My question is how to terminate the #4 wire to the circuit breakers?

[Mark Burns]

Originally Posted by AMURRAY

The #4 wire from the battery solenoid is routed to the instrument. The circuit breakers for the battery bus are daisy chained together. My question is how to terminate the #4 wire to the circuit breakers?

I used #8 wire that goes to a main 60amp breaker nearly hidden in the top of the photo. Then from the main breaker it feeds the main buss.

Notice the two piece buss bar with the joggle due to having two different style breakers to deal with.

The buss bars should be on the breakers or combination breaker/switches.
Then the other wire will run to the switch and then the device.

The idea is to protect the small wires as soon as possible.

Your #4 wire sounds big to be feeding the main buss. Big is good though, except for weight.

I hope I've helped some.

Mark

[az_gila]

Originally Posted by N131RV

I could be off base here, but usually, the main hot wire terminates in the "buss bar" which is a strip of copper which spans the "hot" side of your switches.

Such is the case in many production airplanes

Power flows from the buss bar, through the switch, to a circuit breaker, and then to the item(s) you are powering on that circuit.

So, to answer your question, the main hot does not terminate in the breakers (normally).

Hope this helps,
JP

...and how you define it....

It's not the "Main Hot" if it comes from the battery solenoid as initially described.

It the "Master ON" hot. I'm a bit surprised at #4 wire though. #6 or even #8 is more typical.

One wiring method is to use a copper strip (available from Vans) and attach each breaker to the strip though one of the breaker screw terminals. Fairly easy to do if all of the breakers are in a straight line. The "hot" wire in can then be bolted to an end of this copper strip.

Just like Mark shows above... who posted while I was typing...

[AMURRAY]

Mark,
Thats exactly what I was looking for. The reason I went with the #4 wire is that I have a 65 amp alternator and that is the size wire I ran to the alternator. Probably could have used a #6. Not that I expect to ever pull 65 amps through the panel.
Aaron

[AMURRAY]

According to the AC 43.13 a #4 wire is good for a 100 amps at less than 15 feet of wire. That is at 20C or 70F. Above that temperature the wires need to be derated. The engine compartment will be hotter than 70F. I went with Aero Bobs wiring print for a 60 amp alternator and #4 wire. As an A&P I was taught if I fall between to wires sizes on the wire chart in the AC 43.13 you always use the larger wire. I doubt my alternator will ever produce 65 amps unless my battery is really dead. I have a 60 amp fuse coming off the alternator and will use a 60 amp breaker like Mark did in the panel. I know people who get away with a #4 wire to their starter. I would rather use #2. Is #4 to the panel an overkill? maybe. I could get away with A #6.