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  1. sham
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    sham S B ELECTRICIAN

    Location:
    WEST MIDLANDS
    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 the sockets. Everything else is 5 seconds, for example, lights, shower, and immersion heater. I thought this is wrong but the person who carried out these tests are experienced, not saying they are right. But they could be, as they are busy in testing jobs. Can anybody give me any insight please.
     
  2. johnduffell
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    johnduffell Regular EF Member

    Location:
    uk
    I have a feeling that's been tightened up, but I'm pretty sure the 0.4 applied to portable equipment likely to be held and not to fixed equipment. When was the previous report done?
     
  3. Richard Burns
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    Richard Burns Trusted Advisor

    Location:
    Cambridgeshire
    Business Name:
    Richard Burns
    0.4s is the disconnection time for a final circuit <=32A @230V on a TN earthed installation.
    So it is possible that the shower, if a 40A+ radial, could have a 5s disconnection time.
    Other than that only distribution circuits should have a 5s disconnection time.
    Lights and immersion heaters will not be distribution circuits and are not going to be over 32A so I would expect that they should be 0.4s.
     
    • Agree Agree x 2
  4. sham
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    sham S B ELECTRICIAN

    Location:
    WEST MIDLANDS
    Is it 5 seconds because anything over 32A is not going to be handheld.
     
  5. sham
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    sham S B ELECTRICIAN

    Location:
    WEST MIDLANDS
    Just checked, the showers are 32A mcb protected.
     
  6. johnduffell
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    johnduffell Regular EF Member

    Location:
    uk
    Yes it was tightened up 10 years ago exactly, so it depends when the circuits were designed.
    It was purely related to hand held equipment, now as above it's related to the size of the protective device it whether it's a distribution circuit.
     
    • Agree Agree x 1
  7. westward10
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    westward10 In echoed steps I walk across an empty dream. Electrician's Arms

    Location:
    Northamptonshire
    How old is the Cert as the 16th Ed permitted 5 sec times on fixed equipment circuits, 0.4 applied generally to socket outlets.
     
    • Agree Agree x 5
  8. sham
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    sham S B ELECTRICIAN

    Location:
    WEST MIDLANDS
    08/06/2015
     
  9. johnduffell
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    johnduffell Regular EF Member

    Location:
    uk
    Is that the installation cert or just the last inspection?
     
  10. Richard Burns
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    Richard Burns Trusted Advisor

    Location:
    Cambridgeshire
    Business Name:
    Richard Burns
    table 41.1, etc. from possibly 18th edition (I haven't read it yet)
     

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  11. sham
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    sham S B ELECTRICIAN

    Location:
    WEST MIDLANDS
    Last inspection
     
  12. johnduffell
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    johnduffell Regular EF Member

    Location:
    uk
    So basically you'll need either the installation cert or guess which edition it was designed to.
    Perhaps the previous guy knew some history that's not obvious now, but given that documentary evidence, unless you have other reason to think it was later, i would just follow that and inspect/test according to that. No one can expect you to have a psychic power, you can only report based on what you see.
     
  13. spinlondon
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    spinlondon Trusted Advisor

    Location:
    Harlow Essex
    120V to 230V d.c. used to be 5s for TN installations.
     
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  14. spinlondon
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    spinlondon Trusted Advisor

    Location:
    Harlow Essex
    Maybe he just never bothered buying the newer Reg books, or if he did, never bothered reading them.
     
    • Like Like x 1
  15. Richard Burns
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    Richard Burns Trusted Advisor

    Location:
    Cambridgeshire
    Business Name:
    Richard Burns
    I have checked and that is what the table states; It is that sort of change that I tend to miss, admittedly it will possibly never come up but can be annoying. I know I missed something similar on another reg at the last change.
    Then again it could be the first of the errors:anguished:

    re the OP if the inspection was being carried out in June 2015 then the regulations to which he is inspecting are the 17th edition so there is no reason to have written a 5s disconnection time in the report, it would only be a comment that the installation was designed to different disconnection times.
     
    • Agree Agree x 1
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