A mechanic has installed electric wiring according to an STC, but added 2 feet of conduit through the firewall. Is this installation acceptable?

The installation of electrical wiring for an aircraft must adhere strictly to regulations and specifications outlined in the Supplemental Type Certificate (STC). When the mechanic added an additional 2 feet of conduit through the firewall, this action could potentially affect the overall electrical system, such as resistance, connectivity, and heating, as the original specifications of the STC must be followed precisely.

In this case, the concern revolves around the effect of longer wire lengths on electrical characteristics. If the original STC was designed for specific lengths, then extending that length may exceed the amperage rating for the wiring or components used. This could lead to issues like overheating, which might compromise the safety and functionality of the electrical system. Therefore, adhering strictly to the outlined requirements of the STC regarding wire length is critical.

Options that suggest the installation is acceptable do not take into account the potential risks introduced by modifying the wiring length. Insulation may not address issues of increased amperage or resistance. Hence, the original specifications must be preserved to ensure compliance and safety.