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no busbar

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  • 14-05-2015 7:08pm
    #1
    Aint Eazy Being Cheezy
    Registered Users Posts: 4,631 ✭✭✭


    Just wondering. Looking at a consumer unit out in a small shed. There's a row of mcbs for some lighting circuits in the shed, and outside yard and one socket. If mcb were to be added for a socket circuit, is it bad practice to use 2.5 to supply the mcb, seeing as there's no room on the top shelf to connect with busbar?


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    #2
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    The Cunning Linguist wrote: »
    If mcb were to be added for a socket circuit, is it bad practice to use 2.5 to supply the mcb, seeing as there's no room on the top shelf to connect with busbar?

    Yes.

    What device would be protecting this new MCB?
    In other words what sized fuse or MCB feeds this sub-board?


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    #3
    Aint Eazy Being Cheezy
    Registered Users Posts: 4,631 ✭✭✭Aint Eazy Being Cheezy


    2011 wrote: »
    Yes.

    What device would be protecting this new MCB?
    In other words what sized fuse or MCB feeds this sub-board?

    63A mains fuse, protects the board. The socket circuit is on a 20amp mcb. Am I explaining it properly?


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    #4
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    The Cunning Linguist wrote: »
    63A mains fuse, protects the board.

    Are you sure that there is nothing between the 63A fuse and this sub-board?
    That would mean that a 63A main fuse is protecting that 2.5mm sq. cable, do you see the issue with that?

    Why not just install a proper piece of busbar?

    I assume that the other MCBs are all using busbar?

    What size cable is supplying the shed?

    This work should really be carried out by a qualified electrician.
    It is imperative that this new socket circuit is protected by an RCD.


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    #5
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    Yes.

    What device would be protecting this new MCB?
    In other words what sized fuse or MCB feeds this sub-board?

    Poster is asking about using 2.5 wire to supply an MCB, instead of busbar copper.

    Not ideal but no real risk when supplying a single MCB. The bsd practuce part is becsuse more mcbs can then be looped from that one, loading up the now undersized link.


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    #6
    Aint Eazy Being Cheezy
    Registered Users Posts: 4,631 ✭✭✭Aint Eazy Being Cheezy


    I knew I was missing something. There is an rcd in place. The way the board is laid out is all the lighting mcbs and rcd are on the top din rail, lights before rcd. One socket mcb after rcd on top. Bottom rail has the mains switch fuse over to one side.

    If the socket mcb was placed on the bottom, by itself, the neutral terminated to the rcd neutral bar, earth to earth bar, is it too much of a hatchet job to use a cable to link the other socket mcb to it?


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    #7
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    The Cunning Linguist wrote: »
    I knew I was missing something. There is an rcd in place. The way the board is laid out is all the lighting mcbs and rcd are on the top din rail, lights before rcd. One socket mcb after rcd on top. Bottom rail has the mains switch fuse over to one side.

    If the socket mcb was placed on the bottom, by itself, the neutral terminated to the rcd neutral bar, earth to earth bar, is it too much of a hatchet job to use a cable to link the other socket mcb to it?

    If I were doing this I would prefer to have the RCD fed MCBs beside each other on the bottom row linked with a common busbar.
    Is this possible?


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    #8
    Aint Eazy Being Cheezy
    Registered Users Posts: 4,631 ✭✭✭Aint Eazy Being Cheezy


    That'd be the proper way to do it, but there's not enough slack to move them to the bottom rail.


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    #9
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    The Cunning Linguist wrote: »
    That'd be the proper way to do it, but there's not enough slack to move them to the bottom rail.

    Why, what else is there?


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    #10
    Aint Eazy Being Cheezy
    Registered Users Posts: 4,631 ✭✭✭Aint Eazy Being Cheezy


    Bruthal wrote: »
    Poster is asking about using 2.5 wire to supply an MCB, instead of busbar copper.

    Not ideal but no real risk when supplying a single MCB. The bsd practuce part is becsuse more mcbs can then be looped from that one, loading up the now undersized link.

    Right, but very unlikely that anything extra will be put in. No mcbs will be looped from this new circuit.


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    #11
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    The Cunning Linguist wrote: »
    Right, but very unlikely that anything extra will be put in. No mcbs will be looped from this new circuit.

    Bruthal is correct, you would most likely "get away with it", but why bother?
    This is mains electricity, do it right.

    My advice would be to install proper panel flex, it will only cost about €3 to do it properly.


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    #12
    Aint Eazy Being Cheezy
    Registered Users Posts: 4,631 ✭✭✭Aint Eazy Being Cheezy


    2011 wrote: »
    Why, what else is there?

    Cables are clipped above the ceiling slab. To move the mcbs down to the bottom you'd need to break the slab. There was a cable left to allow for another possible socket circuit, which is going in now, there's just no room for the mcb to go on the top rail alongside the rest.

    Alternatively, you could break the slab and get more slack, or loop off the existing socket, and forget about the new mcb but I'm just looking to see if there's a simpler way whilst maintaining standards.


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    #13
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    The Cunning Linguist wrote: »
    I'm just looking to see if there's a simpler way whilst maintaining standards.

    There is, use 10 sq. panel flex.


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    #14
    Aint Eazy Being Cheezy
    Registered Users Posts: 4,631 ✭✭✭Aint Eazy Being Cheezy


    2011 wrote: »
    There is, use 10 sq. panel flex.

    And there's my answer. Cheers.


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    #15
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Its not great without ferules. And they are not great without a proper ferrule crimper. Nothing is easy in this sector.


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    #16
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    Bruthal wrote: »
    Its not great without ferules. And they are not great without a proper ferrule crimper. Nothing is easy in this sector.

    Yup


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    #17
    Aint Eazy Being Cheezy
    Registered Users Posts: 4,631 ✭✭✭Aint Eazy Being Cheezy


    2011 wrote: »
    My advice would be to install proper panel flex, it will only cost about €3.

    Absolutely bang on the money. :D job done, thanks lads.


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