Re: AV30 Install


Rick Hole
 

To put my previous comment in perspective I looked up in FAA Advisory Circular 43.13-1b the table 11-3 on page 11-15.

 

For the circuit in question, take the breaker or fuse value and read the wire gauge in the left column.  Too small a wire (higher gauge number than listed) is a fire hazard.  Too large is safe but carries other penalties.  For a 22g wire, the breaker should be no larger than 5 amps.

 

This is a common error in homebuilt aircraft.

 

 

Rick Hole

 

From: main@Q-List.groups.io [mailto:main@Q-List.groups.io] On Behalf Of Rick Hole via groups.io
Sent: Saturday, May 14, 2022 10:48 AM
To: main@Q-List.groups.io
Subject: Re: [Q-List] AV30 Install

 

Just a reminder, wire size for both power and ground is determined by the breaker or fuse protecting that circuit, not by the expected load

In the event of a short circuit the wire must conduct high current until the breaker or fuse interrupts the circuit without overheating.

For an extreme example, consider if the load were a 10 mA LED pilot light connected to a 10 amp breaker circuit.  A short at the LED would result in (more than) 10 amps flowing through the wire.   While it is tempting to think we could use perhaps a 24 or 26 gauge wire, plenty good for 10 mA, that wire would glow red hot before evaporating with the possibility of causing other nearby wires’ insulation to melt and a cascade failure result.  Or an in-flight fire.  Hence the wire must hold up for the trip current long enough for the breaker/fuse to blow.

 

Rick Hole

 

From: main@Q-List.groups.io [mailto:main@Q-List.groups.io] On Behalf Of Kevin Boddicker
Sent: Saturday, May 14, 2022 10:11 AM
To: main@q-list.groups.io
Subject: Re: [Q-List] AV30 Install

 

Jim,

What size wire did you use for the install?

 

Will I see you in September? No song lyrics intended.

 

 

Kevin Boddicker
TriQ 200 N7868B  580  hrs
Luana, IA.


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