534.2.6 SPD installation in conjunction with RCDs
If an SPD is installed according to 534.2.1 and is on the load side of the RCD, an RCD with a surge current withstand capacity of at least 3kA 8/20 must be installed, with or without a time delay device.
NOTE 1 Type S RCDs complying with IEC 61008-1 and IEC 61009-1 meet this requirement.
Note 2 If the surge current exceeds 3kA 8/20, the RCD may trip and interrupt the power supply.
534.2.7 Measurement of the insulation resistance
During the measurement of the insulation resistance of an installation according to IEC 60364-6-61, SPDs installed at or near the power inlet or in the distribution board and having a rating lower than the insulation measurement voltage may be disconnected from the circuit.
When the SPD connected to the PE conductor is part of a socket outlet, the SPD shall withstand the test voltage during the insulation resistance measurement according to IEC 60364-6-61.
534.2.8 SPD status indication
An indication function must be provided that the SPD is no longer capable of protecting against overvoltage in the following manner:
- SPD status indicator or
- Separate SPD protection device as indicated in 534.2.4
534.2.9 Connecting conductors
Connecting conductor refers to the conductor from the line conductor to the SPD and from the SPD to the main ground terminal or from the SPD to the protective conductor.
As the length of the SPD connection conductor increases, the overvoltage protection effect decreases, so the optimal overvoltage protection effect is achieved when the SPD connection conductor is as short as possible (it is recommended that the total lead length does not exceed 0.5 m) and does not form a loop.
534.2.10 Cross-section of earthing conductors
The SPD grounding conductor at or near the inlet must be copper with a minimum cross-sectional area of 4㎟ or equivalent.
If a lightning protection system (LPS) is present, an SPD tested to Class I of IEC 61643-1 must be made of copper or equivalent with a minimum cross-sectional area of 16㎟.