In what configuration must SPDs at grounded service entrances be wired?

The correct understanding of how Surge Protective Devices (SPDs) at grounded service entrances should be wired is critical for effective lightning protection and surge suppression. SPDs can be connected in various configurations depending on the system requirements and the type of electrical distribution system in use.

When considering the options provided, it is important to recognize that wiring configurations like Line-to-ground (L-G), Line-to-neutral (L-N), and even Neutral-to-neutral (N-N) each serve specific roles in protecting against electrical surges.

• The Line-to-ground configuration (L-G) provides a direct path for surge currents to be diverted to the ground, minimizing the impact on connected equipment.

• The Line-to-neutral configuration (L-N) offers protection by shunting surges from the line to the neutral, which is commonly used in various residential and commercial systems.

• The Neutral-to-neutral configuration (N-N) involves surge management between neutral points, which can be necessary for certain system layouts.

Because each of these configurations can be implemented effectively in a grounded service entrance, saying that any of the configurations is acceptable emphasizes the versatility and adaptability of SPDs in protecting electrical systems from surges. Thus, the understanding that SPDs can be wired in any suitable configuration at service