TT System and 30mA RCD tripping times

[w crane]

Help!
Sorry having a bad day.
I understand the concept behind touch contact of 50v and the above 1666 ohms. But when physically testing with 17th ed dilog and testing a TT system 30mA RCD. At 1x and 5X what reading would you see on your meter? or would you just test the mechanical aspect of the RCD ( test button). and use the touch voltage calculation (along side the accepted 200ohm figure)?

 

[telectrix]

Rcd fitted on TT or any system needs testing x1/2, x1, x5.

 

[spsparks]

I always work to
1/2 no trip
1x less than 200ms
5x less than 40ms

 

[Deleted member 9648]

I always work to
1/2 no trip
1x less than 200ms, newer bs are less than 300ms
5x less than 40ms

Unless I'm missing something the max disconnection time for a final circuit on a TT is 0.2s....so 200ms max @1x.
The RCD test is to confirm disconnection time,not touch voltage.....the RCd test will confirm that the RCD disconnects within 0.2s to limit the duration of the touch voltage.

 

[spsparks]

I stand corrected and should have read the thread TT doh

 

[IQ Electrical]

Guys, remember that the disconnection time of 0.2 seconds is for a fault of negligible impedance, to save on typing, look at this thread:

http://www.electriciansforums.net/i...stallations/24931-max-zs-tt-inatallation.html