The grounding electrode network for a lighting protection system can be used for the electrical service supplying a building only when:

The grounding electrode network for a lightning protection system can be used for the electrical service supplying a building when no other electrodes are available. This situation allows the lightning protection system's grounding electrodes to also fulfill the purpose of grounding for the electrical service, providing a necessary path to ground for fault currents and other electrical surges.

In environments where additional grounding electrodes are not present, this dual use ensures compliance with safety and code requirements, while also maintaining the needed level of protection against electrical hazards. The use of a lightning protection system's ground can be a practical solution in such cases, effectively serving the function of grounding for the electrical system in the absence of other suitable grounding methods.

The other options present conditions that do not specifically enable this use. Having other electrodes present, local code restrictions, or concerns about the currency of the system are not conditions that allow for the acceptable use of the lightning protection grounding system for electrical service.