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Electrical Question. Consumer Unit.

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Evenin' All,

                       it was fun getting to work today. Firstly, I had left my van's windows open about 5mm at the top to reduce condensation buildup. A Big mistake. The dusty fine snow had found a way in and covered the driver's seat and the steering column and some parts of the dashboard. Joy and bliss I said.


Anyway now to the question. Sparky Sid was installing a new Niglon R.C.B.O. populated consumer unit. It has a main D.P. switch and six R.C.B.O.s.


He always uses one  short length of P.V.C. earth sleeving when assembling these types of consumer units.


Why?


Z.
  • 0
    he does not use T and E for the final circuits, so it is only the incomer that needs covering ?

    I presume he removes that silly braid to the lid.

    Mike.
  • 0
    mapj1:

    he does not use T and E for the final circuits, so it is only the incomer that needs covering ?

    I presume he removes that silly braid to the lid.

    Mike.


    No MIke he leaves the flexible earth bond on the hinged cover as it does no harm and he is lazy.?

    Z.


  • 0
    He always uses one short length of P.V.C. earth sleeving when assembling these types of consumer units.

    Do you mean he twists all the final circuit c.p.c.s together and sleeves them as one?

    Why?

    'cos he's never had to do any testing?


       - Andy.
  • 0
    AJJewsbury:
    He always uses one short length of P.V.C. earth sleeving when assembling these types of consumer units.

    Do you mean he twists all the final circuit c.p.c.s together and sleeves them as one?

    Why?

    'cos he's never had to do any testing?


       - Andy.


    The clue is "one short length".


    Z.


  • 0
    How short is short and what’s the diameter of the sleeving. Am thinking circuits are in signals and the feed is a SWA.
  • 0
    So he can hold the lid up and out of the way. while he eats his sandwiches

    Legh
  • 0
    he uses t&e

    looking at the new rcbo RCBO1-630SS-Specification-Sheet.pdf (niglon.co.uk) it has g/y functional earth lead which is quite long, 

    he cuts off the excess and uses it to connect the stubs of CPCs to the earth bar

    short length of sleeving is for the bits of CPC between sheaf and connectors.

    Thin flexible g/y cable found suitable after using adiabatic, and Sid only uses 6A circuits on his installs


    I think it is not clear on the front of the RCBO what rating the device is. How can you tell from the designation RCBO1-6/30SS that it is a 6Amp OCPD?
  • 0
    Colin Haggett:

    How short is short and what’s the diameter of the sleeving. Am thinking circuits are in signals and the feed is a SWA.


    After actually reading it a bit better it’s a SWA fitted to the RCBO?  Do they only make type AC ones?


  • 0
    Ah, some good suggestions there. Now for clues.


    a, No C.P.C. is involved.


    b, The short length of earth sleeving is less than 50mm long. Perhaps 4mm diameter.


    c. The use is purely mechanical.


    Z.
  • 0
    O.K. to ease the misery.


    Answer. When we install R.C.B.O.s or M.C.B.s with the new modern cage type terminals and a bus-bar below we have to ensure initially that the cages are fully open to ensure correct bus-bar grip by the cage terminal. If we are not careful we can find a bus-bar finger just in "fortuitous contact" with a terminal and not correctly gripped. I found that on a 40 Amp shower circuit M.C.B. once, but amazingly it was tightly held by chance and no overheating was evident. But overheating could occur if the bus-bar finger is not firmly gripped.


    So we unscrew the M.C.B. or R.C.B.O's terminals fully before trying to correctly fit the new bus-bar from below. Some sparks then push the screws in to ensure that the cage terminal is fully open. If we use a screwdriver that is magnetic it can pull on the screw and close the cage terminal slightly thus defeating the operation. If we use a short piece of P.V.C. earth sleeving to push the screws, being none magnetic, it is more reliable, and unlike a copper wire will not stab our fingers.


    Z.

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