What is the recommended rule of thumb for where to install a capacitor?

The recommended rule of thumb for where to install a capacitor is about two thirds of the distance from where the voltage has dropped, specifically by two thirds. This guideline is based on the principle of voltage stabilization throughout the electrical system. Installing the capacitor further along the circuit, rather than nearer the generation source or at the load center, helps to manage the voltage drop more effectively, ensuring that the voltages at the load center remain stable.

When capacitors are placed approximately two thirds of the way along the line, they can support the voltage level effectively by compensating for the inductive effects that typically cause voltages to sag. This positioning optimizes power factor correction and voltage support, improving overall system efficiency and performance.

This approach contrasts with other options, which may not provide the same level of correction or stabilization in voltage. For instance, placing the capacitor at the load center could help in specific applications, but may not effectively address voltage drops that occur further back in the system. Similarly, installing the capacitor at the source or at specific points based on incorrect voltage drop assumptions would not yield optimal results.