Final answer:
The question falls under Engineering and involves connecting a yellow wire of a 4-way flat connector to a left-side black wire, applying proper color-coding practices to ensure safe and correct electrical connections.
Step-by-step explanation:
The subject of this question is within the realm of Engineering, specifically related to electrical wiring and the use of connectors. The task involves connecting wires using a four-way flat connector, which is a common scenario in automotive electrical systems, trailer wiring, and some home electrical appliances.
According to the information given, the yellow wire on a 4-way flat connector should be connected to the left-side black wire. Insulation color-coding is crucial for safety and functionality in any wiring task, as different colors represent different functions in the circuit. For instance, live/hot wires can be various colors including black, which might be the case for the left-side wire mentioned. However, color standards can vary by region, so it's imperative to confirm local codes. Typically, the ground wire is green, yellow, or bare, contrasting the live/hot and neutral wires.