Deflection between support clamps should be how much?

• A. 1/4 inch
• B. 3/4 inch
• C. 1 inch
• D. 1/2 inch

Answer: (D)

Allowing a small amount of movement between clamps is necessary to keep the wiring from being overly stressed by vibration and thermal changes, while preventing it from wandering and chafing on edges or nearby structure. The specified deflection between support clamps is one-half inch, which strikes a balance: it gives the wire a little slack to flex with vibration and temperature, but is small enough to prevent excessive movement that could wear insulation or cause abrasion at clamp edges. If you tried a smaller gap, the wires could be pinched or stressed at bends; if you allowed a larger gap, the bundle could move enough to rub against edges or other components during flight.