hi all can somebody help me

[alworth26]

im just wondering what the trip time on a 30ma rcd with a tt system i think its 0.2 and on a tn system 0.4, does any body no wat the correct times are thank you.

 

[SPECIAL LOCATION]

Chapter 11 On site guide.

start at page 91 thro page 93..

"Operation of RCD's"

or maybe 411.5 TT systems

under Additional protection..

maybe even just read the of whole of Ch 41 starts at page 44 of BS7671...

should answer most points!

:Salute

 

[tom1]

rcd trip time are the same on tt and tn

rcd bs en 4293

200 ms X 1

40 ms X 5

rcd bs en 61009

300 ms x 1

40 ms x 5

 

[Andy™]

its disconection times that are lower for TT, not RCD trip times

 

[alworth26]

we got told in collage under the 17th eddition 0.2 tt 0.4 tn systems

 

[sparkytim]

They are the MAXIMUM disconnection times, not RCD test times.

 

[alworth26]

ok thanks so if some one asks you wats the disconnection time on a ring main what would it be

 

[sparkytim]

As you correctly posted before, TN 0.4 Sec (400 m S) TT 0.2 Sec (200 m S)

 

[alworth26]

ok thanks tim

 

[a1spark]

In agreement with Sparkytim & andy, and adding...

...for Final circuits up to 32A. and with different times for Non -final circuits [distribution ]

...and just to confuse the issue a bit more......changes planned for Ammendment 1.