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Odd MCB issue

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  • 29-01-2020 11:54am
    #1
    un5byh7sqpd2x0
    Closed Accounts Posts: 1,862 ✭✭✭


    Morning,

    Noticed an odd issue with my MCBs last night - two of them which are beside each other on the board look to be linked somehow: upstairs sockets & downstairs sockets. If both or either one is up, then both circuits are live and the only way to kill them is to switch down both MCBs. Any ideas what could be the issue?


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    #2
    kramer1
    Closed Accounts Posts: 305 ✭✭kramer1


    Sounds like it might be a ring main split across 2 mcb s by mistake, what is the rating of the mcb s?


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    #3
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,596 Mod ✭✭✭✭2011


    Agreed.
    One way or another the MCBs are connected in parallel.


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    #4
    un5byh7sqpd2x0
    Closed Accounts Posts: 1,862 ✭✭✭un5byh7sqpd2x0


    kramer1 wrote: »
    Sounds like it might be a ring main split across 2 mcb s by mistake, what is the rating of the mcb s?

    MCBs are 10A. Is this a safety issue? If they’re in parallel is the circuit now a 20A one or somewhere in between?


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    #5
    kramer1
    Closed Accounts Posts: 305 ✭✭kramer1


    Emilee Uninterested Pilot wrote: »
    MCBs are 10A. Is this a safety issue? If they’re in parallel is the circuit now a 20A one or somewhere in between?

    This all sounds really wrong, I'd get a sparks out to find out what's going on.


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    #6
    Maewyn Succat
    Registered Users Posts: 506 ✭✭✭Maewyn Succat


    Emilee Uninterested Pilot wrote: »
    MCBs are 10A. Is this a safety issue? If they’re in parallel is the circuit now a 20A one or somewhere in between?

    No it'll still be a 10 amp circuit. As said your best bet is to get an electrician to have a look at it because something is not right.


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    #7
    BigVanVador
    Registered Users Posts: 17 ✭BigVanVador


    Emilee Uninterested Pilot wrote: »
    Morning,

    Noticed an odd issue with my MCBs last night - two of them which are beside each other on the board look to be linked somehow: upstairs sockets & downstairs sockets. If both or either one is up, then both circuits are live and the only way to kill them is to switch down both MCBs. Any ideas what could be the issue?

    Yeah I agree with Kramer. Its a ring circuit that was split probably by accident when the board was replaced more than likely just needs a 20a mcb to be whacked in and the two circuits joined.


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    #8
    kramer1
    Closed Accounts Posts: 305 ✭✭kramer1


    How many sockets on the affected circuit?


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    #9
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,596 Mod ✭✭✭✭2011


    The OP has highlighted more than one wiring issue. I would expect that a half descent electrician will uncover quite a few more. I would get this looked at sooner rather than later.


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    #10
    punisher5112
    Registered Users Posts: 24,644 ✭✭✭✭punisher5112


    Sockets should be on a 20amp and lights on a 10amp.


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    #11
    un5byh7sqpd2x0
    Closed Accounts Posts: 1,862 ✭✭✭un5byh7sqpd2x0


    Sorry, my bad. They’re light circuits not sockets... 22 bulbs on downstairs circuit and 15 or so upstairs.

    The board wasn’t replaced, it was wired this way day one. The house is pretty new so only discovered this issue this week


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    #12
    punisher5112
    Registered Users Posts: 24,644 ✭✭✭✭punisher5112


    Are they tripping out?


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    #13
    I Am The Law
    Registered Users Posts: 657 ✭✭✭I Am The Law


    It's what is known as an Erroneous Connection, current rules (ET101) require a test to be done on new installations and give detail on how to carry it out.

    Get your SafeElectric spark to sort it for you.


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    #14
    Xertz
    Closed Accounts Posts: 1,069 ✭✭✭Xertz


    This is way beyond DIY issue legally. You need to call in a professional.


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


    Maewyn Succat wrote: »
    No it'll still be a 10 amp circuit. As said your best bet is to get an electrician to have a look at it because something is not right.

    Its likely it would require well over 20 amps to trip one 10a mcb if 2 in parallel. Then the second one would quickly follow.


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    #16
    un5byh7sqpd2x0
    Closed Accounts Posts: 1,862 ✭✭✭un5byh7sqpd2x0


    Xertz wrote: »
    This is way beyond DIY issue legally. You need to call in a professional.

    I've no intention of trying to fix it myself, there's a sparks coming tomorrow to sort it out. I just wanted to know how dangerous this was and how much of an arse kicking I should be giving the original electrician.


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    #17
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,596 Mod ✭✭✭✭2011


    Emilee Uninterested Pilot wrote: »
    I've no intention of trying to fix it myself, there's a sparks coming tomorrow to sort it out.

    That’s good news. It would be prudent to get him to check the entire installation.


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    #18
    adrian92
    Registered Users Posts: 566 ✭✭✭adrian92


    To answer the OP

    As others have said the load side of the MCBs have been looped.

    Remove both MCBs
    Replace with one with,I think, 20 amp rating


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    #19
    adrian92
    Registered Users Posts: 566 ✭✭✭adrian92


    adrian92 wrote: »
    To answer the OP

    As others have said the load side of the MCBs have been looped.

    Remove both MCBs
    Replace with one with,I think, 20 amp rating

    Attached


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    #20
    brightspark
    Registered Users Posts: 2,637 ✭✭✭brightspark


    Emilee Uninterested Pilot wrote:
    Sorry, my bad. They’re light circuits not sockets... 22 bulbs on downstairs circuit and 15 or so upstairs.

    adrian92 wrote:
    To answer the OP

    adrian92 wrote:
    As others have said the load side of the MCBs have been looped.

    adrian92 wrote:
    Remove both MCBs Replace with one with,I think, 20 amp rating


    Did you miss the post where they said it was a lighting circuit?


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    #21
    DublinDilbert
    Registered Users Posts: 5,381 ✭✭✭DublinDilbert


    brightspark wrote: »
    Did you miss the post where they said it was a lighting circuit?

    If it's a lighting circuit the circuits are probably joined at a light switch or two switches are joined.


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    #22
    brightspark
    Registered Users Posts: 2,637 ✭✭✭brightspark


    DublinDilbert wrote: »
    If it's a lighting circuit the circuits are probably joined at a light switch or two switches are joined.

    I'd agree, but that isn't a reason to put them all on a single 20A MCB.


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    #23
    adrian92
    Registered Users Posts: 566 ✭✭✭adrian92


    brightspark wrote: »
    Did you miss the post where they said it was a lighting circuit?

    Yes, I missed that lighting circuits involved.

    The OP originally stated power outlets only (later said lighting circuits involved)

    Given that, I would be reluctant to give any advice .
    Seems to me a need for an electrician required here.


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    #24
    [Deleted User]
    Posts: 7,712 ✭✭✭ [Deleted User]


    2011 wrote: »
    That’s good news. It would be prudent to get him to check the entire installation.

    They’d be leaving themselves open to getting fleeced then. If they’re not tripping then I’d be inclined to leave them.


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    #25
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    brightspark wrote: »
    I'd agree, but that isn't a reason to put them all on a single 20A MCB.

    Its likely he was pointing out a possible cause, not this single 20A as a solution.


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    #26
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    ReginaldSmythV wrote: »
    They’d be leaving themselves open to getting fleeced then. If they’re not tripping then I’d be inclined to leave them.

    Recommending leaving 2 lighting mcbs incorrectly connected in parallel is poor imo.

    And with that level of electrical install, checking the rest of the installation is definitely good advice.


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    #27
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,596 Mod ✭✭✭✭2011


    ReginaldSmythV wrote: »
    They’d be leaving themselves open to getting fleeced then. If they’re not tripping then I’d be inclined to leave them.

    The idea of the MCB is to protect the connected cable from an over current condition. The way these MCBs have been connected means that they cannot provide adequate protection. Leaving circuits without proper protection is inadvisable as is concluding that the circuits are heathy just because incorrectly installed protective devices have not tripped.

    The cost of making an electrical installation safe is generally very small when compared to the value of the property. Don’t be “penny wise and pound stupid”.


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    #28
    brightspark
    Registered Users Posts: 2,637 ✭✭✭brightspark


    Depending on the age of the house, if no other work was done since it was originally installed then the proper tests were not carried out for the certification.


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    #29
    TheBully
    Registered Users Posts: 876 ✭✭✭TheBully


    It’s just a lighting circuit lads, remove the loop on the load side. Problem solved


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    #30
    TheBully
    Registered Users Posts: 876 ✭✭✭TheBully


    brightspark wrote: »
    Depending on the age of the house, if no other work was done since it was originally installed then the proper tests were not carried out for the certification.

    What test? It was an oversight at best


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    #31
    kramer1
    Closed Accounts Posts: 305 ✭✭kramer1


    TheBully wrote: »
    What test? It was an oversight at best

    Erroneous test,but it might not been around at the time, and visual inspection if there's 1.5s going into a 20a breaker


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