disconnection times | Page 2

disconnection times

Recent contents View information Top users
  1. H

    disconnection times for 100mA BS61008 on a tt system

    Gents, tested a pub split load db today in the sticks. before i commence any work, am i right in stating anything over 0.1 on the 100mA side is a fail? did a test on the man 100mA and its disconnecting in 0.25 I've tested the sockets on the 30mA side and they are disconnecting correctly. Pubs...
  2. M

    Disconnection times with off grid application.

    Hi All New to this forum and fairly new to the business too. I have a project I'm putting together which is an off grid house. There are two 5000VA inverters with sufficient battery size and a sizeable generator to switch in once loads exceed about 7kW, which will ADD a further 100A. Here's...
  3. G

    disconnection times?

    found this today on a pre sort-out inspection: all appears fine apart from the downstairs sockets not on the RCD side...split load board to the 16th ed now lets pan down a bit: yep...its TT...heres some more: i wasn`t too impressed with the workmanship here either: went into...
  4. Toby Kuhnert

    Max disconnection times for 50a shower circuit ?

    Hi guys, Just doing an EIC for a recent dis board change, I also installed a 50a (type b 60898) shower circuit for an 11.5KW shower. I am looking through my regs trying to find whether it comes under the 5s disconnection time...? I know 0.4s is for circuits less than 32A and non-distribution...
  5. J

    Calculate the min size of cpc giving consideration to disconnection times and thermal

    Hi everyone, On the drawing it says the system's TN-C-S with declared Ze = 0,008 Ω and prospective fault current declared as 50kA When I calculate If = Uo / Zs = 230 / 0,716 = 321 A . With this value there's no way to match with 10A curve at fig. 3A6 (appendix 3) But if I calculate the...
  6. T

    disconnection times

    Tn system disconnection time 0.4 s under 32a , 5s over 32a So if a circuit isnt protected by rcd, how do you know if the circuit breaker is tripping less than the maximum disconnection times. Does it rely on low max zs values and ze
  7. S

    disconnection times and RCD

    On the 2391 training course for all of this week and something popped up that I would like to what other people made of it. So we are talking disconnection times, and the question of RCD's pop up. More to the point, circuits not meeting the required disconnection times. I thought I would use...
  8. R

    max allowable disconnection times?

    hi guys, what is the max allowable disconnection time times under fault conditions for kitchen lighting, bedroom socket outlets and also for a shower? thanks in advnace i appreciate all your help
  9. R

    disconnection times

    Circuits under 32A the disconntion times would be 0.4 and anything over woud be 5 am i right.
  10. D

    Disconnection times

    Hi all, can someone tell me what the disconnection time is for circuits supplied from a distribution circuit?
  11. La Poste

    Disconnection times

    This might help a few of us suffering the 2391 exam. Maximum disconnection times for a nominal rms line voltage to earth, U0 of 230V Firstly for a TN system: Final circuits not exceeding 32A = 0.4s Final circuits exceeding 32A = 5s Distribution circuits = 5s For a TT system Final circuits...
  12. silver surfer

    disconnection times v voltage bands

    Guys BS 7671 table 41.1 shows that a disconnection time of 0.4 secs for 120<volts to <inc 230 volts, and a disconnection time of 0.2 at 230< to < inc 400v. (TN systems). My query is with a 10%+/- tolerance which could possibly increase 230 volts to 253 volts hence taking your 230v 0.4s disc...
  13. V

    Disconnection times for 30mA RCD at 5 times current.

    Hi guys ths is my first time on here and relatively new to electrics. I was asked to find the times of disconnection needed for 5x and 1x. I was wondeering if anyone could give me a push in the right direction by pointing out where i could find such useful info inthe BS 7671 or onsite guide...
  14. S

    disconnection times

    Hi Guys, Wonder if any of you could try and explain to me if the reason for disconnection times for fuses /proctective devices etc. As on one hand, i was told at college it is to protect the cable from catching fire etc, and then iget the impression the reason for having say 0.4 disconnection...
  15. B

    Disconnection Times

    I've always wondered why BS7671 states that a disconnection time of 0.4s is required for circuits NOT exceeding 32A and for circuits exceeding 32A it is 5s Surely you would want the higher current to trip quicker? Can someone clarify this?
  16. J

    Disconnection times

    Hello all I no the disconnection times for TN circuits are 0.4s for final ccts with an (in) not exceedind 32A AND 5 s for final circuits exceeding 32A Distrubution ccts I have just installated some lights within a industrial building in a riser and have tested all came back ok just have...
  17. T

    Disconnection Times

    Hi all, Just got a query regarding what values to use from the Red Book 32a Ring Main Domestic Circuit. Do I use the 0.4s Disconnection times or the 5s Disconnection times? regards Tom
  18. J

    Disconnection Times

    Am l right in thinking that its 0.4 seconds for under 32A and upto 5 seconds for anything 32A and above? If so why is that? :confused:
  19. D

    disconnection times

    would someone please explain the reasons for having a 0.4 second disconnection time and a 5 second disconnection time, why is there a big difference between the two readings :confused:
  20. P

    disconnection times

    guys, don't have my regs book handy at mo disconnection time for a tns system is 0.4 sec is'nt it

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

YOUR Unread Posts

This website was designed, optimised and is hosted by untold.media Operating under the name Untold Media since 2001.
Back
Top