Correct installation of surge protection devices

Due to the increased installation of sensitive electronic equipment, the use of surge protection devices is becoming more prevalent. Our Technical Team are receiving an increasing number of enquiries regarding the correct connection of these devices. Surge protection devices provide protection against transient overvoltage, however they do not protect against prolonged overvoltage. 

Appendix F of AS/NZS 3000:2018 provides information on the installation of surge protection devices.

Where to install surge protection devices

Surge protection devices can be installed at the main switchboard (primary surge protection devices) or at sub-boards (secondary surge protection devices).

Surge protection devices should be installed after the main switch (but prior to any RCDs) and should be protected by a suitable fuse or circuit breaker (refer to clause F1.2.4 of AS/NZS 3000:2018). 

Figures F1 and F2 from AS/NZS 3000:2018 below show connection arrangement for primary and secondary surge protection devices respectively. It should be noted that some devices may have specific installation requirements as specified in the manufacturer’s instructions.