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disconnection

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  1. G

    Disconnection times, some clarification

    Evening, just revising for 18th update course and wondered if someone can just clarify something. (I might just be confusing myself, too long staring at the BBB) Reg 411.3.2.2 ii) does that also include luminaries? I understand 411.3.4 applies. Do notes 1 & 2 of 411.4.4 mean that the use of an...
  2. Pretty Mouth

    Short circuit disconnection times

    Could someone shed some light on the following please? 411.3.2.1 implies that the 5s / 0.4s disconnection times only apply to earth faults. I've not found anything else in the regs that suggests they apply to short circuits. 435.5.2 says faults should be disconnected before the fault current...
  3. S

    RCD disconnection times on 2018 forms

    Evening all, happy Friday! On the new forms there is only one column for RCD disconnection times. I understood you would just record the highest of the 5x readings but on looking around to confirm I found this article on Professional-Electrician: "The model forms in Appendix 6 have been...
  4. J

    Changes to the requirements on recording RCD disconnection times

    Hi everyone, long term visitor to the forum but first time posting a question... be gentle This question is with regards to the changes to the 18th edition certificates, which only require one disconnection time recorded. When recording the highest value taken when carry out RCD tests, Reg...
  5. spud1

    Disconnection time of a 32Amp Cooker circuit with a panel socket?

    Hi, What would be the Maximum disconnection time for a 40Amp domestic Cooker circuit in a TNCS system be, where it has a 13A socket outlet on the panel/isolator faceplate? Obviously a final circuit >32A would be 5 secs but I was just interested as to whether the presence of a 13A socket outlet...
  6. gazdkw82

    Ax disconnection times 32A+

    I don't know why I've not noticed before but the disconnection time for final circuits greater than 32A is 5 secs on a TN earthing arrangement. Does that mean a shower has a disconnection time of 5 secs? Although this circuit would also fall under protection of an RCD?? Also, cooker circuits...
  7. sham

    looking through previous certificate and have a question about disconnection time.

    On a domestic inspection and testing certificate or conditional reports, I always put maximum disconnection time permitted by BS7671 as 0.4 sec. I've been given a testing job for an HMO property and on the previous conditional report, the maximum disconnection time of 0.4 sec is only given for...
  8. R

    Automatic disconnection of supply

    Can the above method alone be classed as basic protection according to 131.2.1 it can. Based on that regulation you can leave live terminals exposed if supplied by a 30mA RCD
  9. R

    Disconnection times for finals

    Just received a completed test sheet from an installer on a TN system with the max permitted disconnection time column filled in for the lighting circuit and 20A heater circuit as 5secs, surely 0.4
  10. P

    Disconnection times help

    Hi all just a little bit of advice at the company i work has just had a condition report done and they have marked down excessive zs for a 63a type d breaker but they have put it at 0.4 disconnection time it is a permanent fixed compressor I thought this would have been 5 sec it also has a b.s...
  11. John Lundrigan

    I'm confused about Type C Breaker Disconnection Times

    Hi All, When I consult Table 41.3 for a Type C Breaker rated 16A I see s max Zs of 1.37 Ohms. However this value is defined for both a 0.4s AND 5s disconnection time. This is obviously correct so I am missing something. Fig 3A5 also shows the table 0.1s to 5s. Can anyone explain please...
  12. Dave Rudderham

    RCD Disconnection query - pondering

    As an interested and pondering student, I noticed an "error" today that my tutor is unable to clarify to me. In the big yellow book, table 41.1 shows Maximum disconnection time on a TN system at 230v~ is shown as being 0.4s, yet 415.1.1 states "an operating time not exceeding 40ms." If my maths...
  13. S

    Deadly Disconnection here in Minorca!

    Presently on holiday in Cala Blanca, Minorca and came across this situation. The meter box is built into a wall outside a now disused restaurant along the pavement, the door is completely missing and the clear plastic cover over the 4 wire cut out has been broken and removed. It would appear...
  14. Bob Geldoff1234

    NIC QS Assessment charge

    Not long had my Approved NIC/EIC assessment and had to be QS assessed.This took an extra half a day(on top of the other half a day for the yearly assessment).Just got the bill for the half day charge.......£366!:eek::mad::( Feel ripped off or what. Have any of you guys had to pay this fee?
  15. Edtwozeronine

    Homework help

    I'm looking for the section in my on-site guide that covers disconnect times for circuits over 32a. In my regs class my homework features a circuit with a type B 45a RCD. EDIT: oops never mind I now see it says anything exceeding 32a must not be more than 1 second. I thought there was a more...
  16. B

    Maximum disconnection times

    Hi does anyone know max disconnection times on tn-s system for: 16A radial 6A lights 32A distribution Cheers
  17. M

    Would you replace this RCD?

    This is a new RCD, came in the CU. The max disconnection time I need to comply with is 400ms (Table 41.1 TN ac 230V). From a new RCD I'd expect something roughly in the region of 30ms (for a 30mA fault test). What I'm getting is 234ms (x0.5 there's no disconnection and x5 it's a 13ms...
  18. W

    Disconnection times

    Hello I understand why you need to find out the pfc to ensure breaking capacity is adequate. But I'm struggling to understand minimum fault current. Tncs e.g 230/0.35 =657 amps I think it's if the system has enough fault current to trip the breakers in time e.g a ring would be 3-5 times 32...
  19. Z

    Verifying SWA CPC suitability disconnection times / adiabatic equation

    As you may know looking at some of my posts I've been thrown back in the deep end recently – and don’t have much experience with complicated calculations. As this is the first time I've used SWA to go from the main supply to the primary CCU, and as I'm using the steel armour as my CPC, rather...
  20. 1capybara

    Table 41.3 Max earth fault loop impedence (Zs)

    The heading of table 41.3 says it shows " max earth fault loop impedance Zs for Circuits Breakers..... giving compliance with 0.4s disconnnect time of 411.3.2.2 and 5s disconnnect time of 411.3.2.3." 411.3.2.2 is for final circuits not exceeding 32A. 411.3.2.3 is for distribution circuits and...

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