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16A on Ring

RustyH
Evening all,


I have a client who is looking for their swimming pool heat pump to be wired up. Manual requests for a 16A connection (although client has been running off a 13a plug!!).

The layout of the house and garden restricts the direct connection to the CU to being long and messy. 


The most direct route is to the lower socket ring. Im sure I remember reading on the old forum that a 16a RCD can be classed as a FCU. 

I can not seem to find reference to this in the regs though, is it stated in there?


If it is acceptable I could spur off this lower ring, in to a weatherproof CU with a double pole 16A RCD, then run SWA up the garden to the heat pump. 


Cheers

Rusty

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  • 0
    RustyH:

    Just so I understand, why does a 13A FCU Spurred from a ring and feeding a 1.9Kw device that would probably be deemed as fixed would be totally inappropriate?


    As mentioned in the previous posts, there is the motor inrush to think about so not to cause nuisance tripping, but as the client has been running this on a 13A plug with no blowing of fuses up tripping, the inrush must be below a current, or for a short enough time that doesnt blow / trip fuses.


    Then there is the MIs, thanks to Olympus for finding them. I believe from the points in the MIs, the only one that would deviate is the american term of a dedicated branch (I.E: its own dedicated feed).


    However, the above spur idea would meet the required circuit protection


    The Mis mention "DQG have a leakage current that may exceed 10mA", I have no idea what a DQG is, but over 10mA and 543.7 comes into play. And other devices on the ring will add to the leakage.

    The 75degC requirement means a higher temperature rated cable might be needed, at least for the connection. It is the only requirement in capital letters.

    They also say a dedicated circuit. Ring circuits can be prone to discontinuous conductors, I have had a rodent problem, I know.

    Can't think of any more at the moment.

    You can call me Oly :)


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  • 0
    RustyH:

    Just so I understand, why does a 13A FCU Spurred from a ring and feeding a 1.9Kw device that would probably be deemed as fixed would be totally inappropriate?


    As mentioned in the previous posts, there is the motor inrush to think about so not to cause nuisance tripping, but as the client has been running this on a 13A plug with no blowing of fuses up tripping, the inrush must be below a current, or for a short enough time that doesnt blow / trip fuses.


    Then there is the MIs, thanks to Olympus for finding them. I believe from the points in the MIs, the only one that would deviate is the american term of a dedicated branch (I.E: its own dedicated feed).


    However, the above spur idea would meet the required circuit protection


    The Mis mention "DQG have a leakage current that may exceed 10mA", I have no idea what a DQG is, but over 10mA and 543.7 comes into play. And other devices on the ring will add to the leakage.

    The 75degC requirement means a higher temperature rated cable might be needed, at least for the connection. It is the only requirement in capital letters.

    They also say a dedicated circuit. Ring circuits can be prone to discontinuous conductors, I have had a rodent problem, I know.

    Can't think of any more at the moment.

    You can call me Oly :)


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