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Wire size. Master relay to Bus

Bsquared

Well Known Member
Doing some planning for my main bus. Can anyone tell me the wire gauge of the master relay to bus cable from the FWF kit? Vans P/N WH-P912
 
Thanks Scott. I figured it 8 but wanted to make sure. With everything turned on (modest VFR panel) lt looked like I needed to size for about 30 amps.
 
AC 43.13

AC 43.13 is a great reference for this. The wire sizing chart will give you the ability to choose the correct gauge for any wire based on voltage, drop allowed, current expected, free air or conduit and even intermediate or continuous use. AC 43.13 also covers many of the skills you will need to develop in other areas you will need (riveting etc.) in the construction of the kit. I consider it a required companion to the kit instructions.
 
AC 43.13 is a great reference for this. The wire sizing chart will give you the ability to choose the correct gauge for any wire based on voltage, drop allowed, current expected, free air or conduit and even intermediate or continuous use. AC 43.13 also covers many of the skills you will need to develop in other areas you will need (riveting etc.) in the construction of the kit. I consider it a required companion to the kit instructions.

Just remember it is rarely updated, thus some of the data found therein is wrong.

Few users read the very first line on AC43’s signature page. It says (emphasis mine):

This advisory circular (AC) contains methods, techniques, and practices acceptable to the Administrator for the inspection and repair of nonpressurized areas of civil aircraft, only when there are no manufacturer repair or maintenance instructions.

The legal basis is found in FAR 43.13(a), also quoted on the title page:

... each person performing maintenance, alteration, or preventive maintenance on an aircraft, engine, propeller, or appliance shall use the methods, techniques, and practices prescribed in the current manufacturer’s maintenance manual or Instructions for Continued Airworthiness prepared by its manufacturer, or other methods, techniques, or practices acceptable to the Administrator….

While doing background for a Kitplanes article, I spoke with a representative in the FAA office responsible for AC43. He explained that FAA managers realize industry techniques and practices change and improve with time. However, updating AC43 is not as easy as one might think. A change requires administrative and regulatory due process, thus older data tends to remain as the minimum standard unless clearly proven unsafe. Per the signature page, AC43 may only be used in the absence of other, more up to date information, notably manufacturer’s data and established military and industry standards. A fabricator or mechanic is encouraged to use a better method, technique, or practice, assuming he can produce supporting data acceptable to the Administrator. When performing maintenance or repair on a certified aircraft, FAR 43.13(a) requires the use of methods stated in the manufacturer’s most current instructions. Builders of EAB aircraft are exempt from Part 43, but are well advised to consider its contents.

I return you to your regular programming....;)
 
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