Installation of a surge protector device (SPD):
Place the SPD as close as possible to the panel to be protected.
Drill and punch a hole in the SPD housing in an unusually high location to shorten the connecting wires from the SPD lugs to the circuit breaker in the next panel (or fused disconnect lugs).
Use a close-nippled connection with wires going on to the first breaker at the top of a panel wherever possible. This guarantees that all loads connected to the panel are adequately protected.
Connect the SPD to the breaker panel with AWG #10 stranded wire or bigger (readily available and easy to install). Within the wiring, avoid sharp bends and excessive length. Neat installations are not always the most successful. The best connections are short and direct.
SPDs should connect to a properly rated circuit breaker rather than the panel’s main lugs. A fused disconnect switch should be utilised to connect with the lines and facilitate SPD servicing where circuit breakers are unavailable or impractical.