Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 34 replies
  • Subscribers 32 subscribers
  • Views 3214 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

BS7671;2018 Minor works certificates.

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


What do you actually think of them?


Andy B.
Parents
  • 0
    Graham


    Yes 30mA RCDs need testing at 5 x I delta n to verify they will trip at not more than 40ms but we need to verify at a lesser current than 150mA coursing through someones body they will also trip in a safe time. Reference to the IEC shock current curves would seem to suggest this? As for testing at more than 5 x I delta n at "higher than 5 times its rated residual operating current", as suggested in the Note to 643.8, I will ask again what does that prove? How about a test current of 5A that should operate any sticky 30mA RCD.


    For fire and fault protection 643.7.1 directs us to use an RCD tester to BS EN 61557-6 which may not be able to deliver test currents at 5 times higher rated RCDs. 643.7.1 directs us to Table 3A of Appendix 3. 


    So we need to know what the rating of the RCD is and the purpose for which it is installed?


    So Graham head above the trench time. For additional protection what current(s) would you apply to the RCD and what maximum trip time would you expect? The same question for a 300mA RCD, time and not time delayed, provided for fault or fire protection?
Reply
  • 0
    Graham


    Yes 30mA RCDs need testing at 5 x I delta n to verify they will trip at not more than 40ms but we need to verify at a lesser current than 150mA coursing through someones body they will also trip in a safe time. Reference to the IEC shock current curves would seem to suggest this? As for testing at more than 5 x I delta n at "higher than 5 times its rated residual operating current", as suggested in the Note to 643.8, I will ask again what does that prove? How about a test current of 5A that should operate any sticky 30mA RCD.


    For fire and fault protection 643.7.1 directs us to use an RCD tester to BS EN 61557-6 which may not be able to deliver test currents at 5 times higher rated RCDs. 643.7.1 directs us to Table 3A of Appendix 3. 


    So we need to know what the rating of the RCD is and the purpose for which it is installed?


    So Graham head above the trench time. For additional protection what current(s) would you apply to the RCD and what maximum trip time would you expect? The same question for a 300mA RCD, time and not time delayed, provided for fault or fire protection?
Children
No Data

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines