The size of grounding electrode conductors is determined by the size of what?

The size of grounding electrode conductors is determined by the size of the largest ungrounded conductor in the system. This is because grounding electrode conductors must be adequately sized to ensure that they can safely carry fault currents that could occur during an electrical fault, such as a short circuit. The largest ungrounded conductor sets the baseline for determining the appropriate size of the grounding conductor because it represents the maximum current that could potentially flow through the system. Therefore, the grounding conductor needs to be sufficient to handle this maximum potential load, ensuring both safety and compliance with electrical codes.

The other options do not directly influence the size of the grounding electrode conductors in the same way. The total load on the system, the type of electrical device, and the distance from the ground source are secondary considerations and do not dictate the fundamental sizing requirement tied directly to the ungrounded conductors.