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Lights with no earth

  • 31-01-2023 10:59am
    Registered Users Posts: 1,240 ✭✭✭

    None of the lights wiring in my parents house has earth connection at switch or ceiling rose, its just phase & neutral only. Just to educate myself a little before I talk to an electrician can I ask is it possible to fit something like an RCD or similar in consumer unit that would make the system safer in case of an accident (instead of the basic trip switch breaker). A total house rewire is the long term plan as part of a total revamp of house but that's at least another year or two away.


  • Registered Users Posts: 5,379 ✭✭✭DublinDilbert

    Fit a doubly insulated fitting and there will not be any safety issue as the earth is not required. Doubly insulated fittings will be marked with one box inside another one and there will be no earth connection. Most simple pendants are all plastic and doubly insulated.

    An RCD will not make it any safer as there would be no path back to earth for any fault currents into the metal enclosure.

    Lots of houses have non earthed light fittings, but it is not something I would personally ever do.

    Post edited by DublinDilbert on

  • Registered Users Posts: 6,729 ✭✭✭zg3409

    It met the safety requirements at the time. Most lights are not metal and in worst case scenario that a metal light fitting became live and someone touched it, it is likely the light will be off at the time (changing a bulb) and if light was on they would be standing on a chair and get a minor shock as a result of being in a chair isolated from the ground.

    Typically lights are still not wired into RCDs or elcbs even on new houses as nuisance tripping is more trouble then the extra safety it introduces. On new houses there is an earth at lights for metal light fittings but it barely adds extra protection and it's unlikely anyone in Ireland was ever killed from it.

    If you really want to improve safety get an electrician to give all the house a full health check. Replace all old work plug sockets with new ones and ensure water pipers in hot press and under sink are earthed. Check for dodgy wiring and old worn switches and appliances such as immersion heaters.

    Do t charge phones at night as these are major killers and fit smoke alarms in all rooms except kitchen.

  • Registered Users Posts: 4,957 ✭✭✭kirk.

    The shock risk from plastic switches and double insulated fittings is fairly low

    It might save you if you forget to switch off when changing a light etc

    T+E should always have RCD protection due to the type of cable as well as any shock risk in house

  • Registered Users Posts: 4,745 ✭✭✭meercat

    All lighting circuits are now required to have rcd protection

  • Registered Users Posts: 4,957 ✭✭✭kirk.

    A lot of things wrong here

    Class 1 Metal fittings need earthing its important

    You can't depend on lights being off either

    Afaik meercat can correct me , you can connect lighting circuits to a shared RCD or rcbo , rcbo being preferred

    lighting rcbos don't present much risk of blackout

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  • Registered Users Posts: 4,745 ✭✭✭meercat

    Yes you can put lights on a shared rcd but the preference is one for upstairs lights and another for downstairs(careful about landing light neutral).obviously the more rcds the better.don’t put them on the socket rcd. the new distribution boards come prewired with 2 rcbo’s(and surge protectors.

  • Registered Users Posts: 4,957 ✭✭✭kirk.

    I meant a dual RCD board like the old UK system I thought that was allowed

    I wouldn't put multiple lighting circuits on a single RCD that would be bad design

    Upstairs lights and downstairs sockets on one RCD

    And the other way round for the second RCD

    Not the greatest system but not the worst

    Anyway like you say if the new boards come with lighting rcbos it's academic discussion anyhow

  • Registered Users Posts: 1,240 ✭✭✭monseiur

    Thanks for replies.

    So, if I understand you correctly I can ask electrician to replace lights MCB with a suitable RCD, he previously checked all wiring etc. and gave it the all clear. House is a bungalow type and will be totally rewired within the next 18 months

  • Registered Users Posts: 4,315 ✭✭✭blackbox

    I don't think an RCD will work on a non earthed circuit.

    There is no doubt that the newer regulations give increased safety, but it was already a very low risk. How often have you heard of someone being killed when changing a light bulb (the only time you make physical contact with the light fitting)?

    If the house is to be rewired it will have to be done according to the regulations in place whenever it is done.

  • Registered Users Posts: 4,957 ✭✭✭kirk.

    It works fine

    The main function of 30ma RCDs was always shock risk

    So any bathroom exposed wiring, metal shelving drilled through switch drops , shock changing outside light

    They work normally for all those situations

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  • Registered Users Posts: 209 ✭✭Bruthal.


  • Registered Users Posts: 209 ✭✭Bruthal.

    There won't even be a minor shock standing on a chair, via the path through the chair anyway, unless the chair is conductive, connected to the ground and not laminate floor etc, and the user is in bare feet. Doesn't happen. The path through a wooden chair would be multi mega-ohms.

    There could be a nice surprise between 2 or more points of contact with the light fitting itself, ie - fingers across the pins as one example.

  • Registered Users Posts: 4,957 ✭✭✭kirk.

    Ya a spark I trained with used to hold a live wire at an upstairs switch

    He'd get me to stick the phase tester to his arm and lit up

    Sounds like lunacy now probably is

  • Registered Users Posts: 4,745 ✭✭✭meercat

    Opening up a can of worms installing an rcd on existing lighting circuits with the possibility of nuisance tripping. Rec will have to test and provide a certificate.they’ll have to issue a notice of potential hazard with no earths and any other issues he sees when he removes the cover of the distribution board . Unlikely they’ll do it.

  • Registered Users Posts: 4,957 ✭✭✭kirk.

    Minefield connecting to an existing RCD or adding RCD to old work

    Most of the time it'll be alright but you'll get the "everything was ok before you came " once in a while

  • Registered Users Posts: 1,157 ✭✭✭TheShow

    Just to add a comment, my bathroom light packed in the other day, it’s a led array so I can’t just replace the bulb. I picked up a new light to replace it. The new light has an earth wire, but where I was going to install doesn’t have an earth wire. Will it be ok just to hook it up as is without having a spark to put an earth connect in?