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BS7671;2018 Minor works certificates.

Sparkingchip over 5 years ago

Are you all organised and have a supply of the new certificates to hand?

What do you actually think of them?

Andy B.

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0 gkenyon over 5 years ago
Philip Wood:

For additional protection the worst case scenario should be used, and this would normally be the 1Δn reading. No idea why they have removed the 5Δn column?

That's interesting ... surely the Note to Regulation 643.8 implies that where RCDs are used for Additional Protection, it's the longest @ 5I_Δn which is required ???

Where RCDs are used for Fault Protection, Regulation 643.7.1 applies. The disconnection times required for final circuits are in Table 41.1, and therefore (from Table 3A), for example:

TN system, the disconnection time of 0.4 s might be achieved at I_Δn and therefore we can use that

TT system, the disconnection time of 0.2 s might not be achieved at I_Δn and therefore the disconnection time should to relate to 5I_Δn (if, as per the Note to 643.7.1 states, we take into account the operating characteristics of the device per Table 3A in Appendix 3) - that is unless your tester has a 2I_Δn setting

Where the RCD provides both fault protection and additional protection, which is the "worst-case"? Well, a test at 5I_Δnwould cover both?
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0 gkenyon over 5 years ago
Philip Wood:

For additional protection the worst case scenario should be used, and this would normally be the 1Δn reading. No idea why they have removed the 5Δn column?

That's interesting ... surely the Note to Regulation 643.8 implies that where RCDs are used for Additional Protection, it's the longest @ 5I_Δn which is required ???

Where RCDs are used for Fault Protection, Regulation 643.7.1 applies. The disconnection times required for final circuits are in Table 41.1, and therefore (from Table 3A), for example:

TN system, the disconnection time of 0.4 s might be achieved at I_Δn and therefore we can use that

TT system, the disconnection time of 0.2 s might not be achieved at I_Δn and therefore the disconnection time should to relate to 5I_Δn (if, as per the Note to 643.7.1 states, we take into account the operating characteristics of the device per Table 3A in Appendix 3) - that is unless your tester has a 2I_Δn setting

Where the RCD provides both fault protection and additional protection, which is the "worst-case"? Well, a test at 5I_Δnwould cover both?
Cancel
Vote Up 0 Vote Down

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