disconnection

  1. 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...
    • MRL
    • Thread
    • application disconnection disconnection times off grid times
    • Replies: 1
    • Forum: UK Electrical Forum
  2. M

    NICEIC Certification Scheme help filling in niceic test certs please

    The test cert is for a transportable building I have fill in a test not done it since college, i dont know what to put in the max disconnection time for Bs60898 MCBs protected by a 63A 30ma RCD main switch, no circuit exceeds 32A is it 0.4s for a TN system is it 0.2s for a TT system or 300ms...
  3. S

    RCD test

    hello every one can some body help me please in this particular question?When tested at Idn time 5 , a 30nmA RCD protecting a 230 V a cooker circuit incorporating a socket outlet in its control unit must trip within : time please
  4. D

    DISONECTION TIMES- Circuit Ratings

    Stupid question that i need answering. How do what your circuit is rated at? I know that if its above or below 32A there are different disconnection times depending on the type of earthing system
    • Davetherave
    • Thread
    • circuit circuits different disconnection question ratings times
    • Replies: 11
    • Forum: UK Electrical Forum
  5. S

    trouble with 2394/2395 revision queston

    hey guys.... ive downloaded some revision questions for my 2394/95 course i have booked for august and ive come across a question im a little unsure about......even when i have used the regs and GN3 to help. a little help would be greatly appreciated as there is no answer sheet for the...
  6. S

    TT distribution circuit

    Hi, a bit of advice required. I need to install another d.b to a garage, the tails are to be split. The earthing system is TT, the cable is armoured, clipped to the side of the building & over to the garage on a small cantenary wire. As it is TT would the distribution cable need to have rcd...
  7. W

    0.4 disconnection time

    Hi we all know about the 0.4 disconnection time, but why 0.4 has this something to do with body resistance, can anyone shed light on this.
  8. 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...
    • GLENNSPARK
    • Thread
    • disconnection disconnection times times
    • Replies: 14
    • Forum: UK Electrical Forum
  9. Robotstar5

    E7 disconnection

    I want to remove the fused isolator that fed an old storage radiator, neutral & earth no problem, but the live comes from the timeswitch protected by a sealed cover. Service fuse seals are often missing :D but not sure about timeswitch? I thought of terminating in a small henley block?, but open...
  10. M

    Cable size for single phase motor control panel

    Hi all, Your help would be appreciated. We are mainly domestic sparx so I havn't much experience with cable sizing for motors. On site, we need to supply a motor control panel which operates the sewage pump. There are in fact two pumps but I think they switch between periodically to prolong...
    • mark_
    • Thread
    • cable cable size control disconnection discrimination motor panel phase required single single phase size
    • Replies: 13
    • Forum: UK Electrical Forum
  11. 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...
  12. M

    Am I at risk of disconnection?

    Opinions needed...past the halfway mark in a major house refurb. (for info: am qualified electrician - although it's not the day job - Part P handled via Building Control). Top half of house is still a building site, lower half of house is sort of okay, but rough round the edges. Rang up EDF...
  13. S

    Zs on rcbo

    Hi guys had a conversation with the boss in the office after work today about a zs I got on a 32A c type rcbo bs 61009, the earthing system is TN-C-S, he said he wasn't worried I got a zs reading of 0.90 even though a type c 32A rcbo has a max zs of 0.72 his words were "it's just like a TT...
  14. R

    Notification of a disconnected circuit

    Do I need to notify the disconnection of a shower circuit? I have disconnected and made safe at the consumer unit and confirmed at the business end that the circuit is de-energised. If I do need to notify, on what basis am I doing so? Alteration in a special location? Sage advice/experience...
  15. 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...
    • JuniorSparky
    • Thread
    • calculate cpc disconnection disconnection times size thermal times
    • Replies: 28
    • Forum: UK Electrical Forum
  16. JD6400

    Changing a panel board with temporary DNO disconnection ?

    We have a a grain store refurb that needs completing , but in order to get a new panel board in on the 400a head we will need e-on to temporally disconnect the supply while the old one is removed and the new one is mounted and retailed . Has anyone else done this before and if so what sort of...
  17. D

    Fault currents providing instantaneous disconnection/ thermal withstand of cables.

    HI. I have recently installed some circuits at work and i am having problems proving that the fuses will disconnect before the cables used get to their max permitted temperature. The two circuits are as follows: 1. 6mm L,N,E singles connected to a 32 amp HRC fuse...
  18. 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
  19. S

    Disconnection Relay G83 - Embedded Generator

    I understand that a disconnection relay must disconnect in the event of mains supply failure, however by what means does it achieve this? If a sterling engine type generator is connected into a final circuit, what is the disconnection relay monitoring to register the mains failure? If anyone...
  20. rustynails

    2392 Question: Maximum earth loop impedance for 20A BS88 (gG) fuse

    What is the maximum earth loop impedance to BS7671:2008 for a circuit protected by a 20A BS88 (gG) fuse giving a 5 second disconnection time is: A: 7.42 B: 2.91 C: 1.84 D: 1.35 The green book says the ln for this type of fuse is 78A p299, that doesnt give you the right answer though. :confused5:
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