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Any reason I can't install an RCD on a generator.

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  • 29-10-2022 4:17pm
    #1
    The Continental Op
    Registered Users Posts: 6,921 ✭✭✭


    I've just found an old but brand new MEM combined 13Amp socket and RCD.

    Is there any reason I can't install this as a replacement for a double socket on a 3KVA generator, obviously I'd only end up with one socket.

    It was just a way to use it rather than stick it back in the box and loose it for another 20 years.

    My only hesitation is that the generator output might be "dirty" and trip the RCD?

    Wake me up when it's all over.



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    #2
    kirk.
    Registered Users Posts: 4,957 ✭✭✭kirk.


    What type of generator

    AFAIK an RCD won't operate on some Genny's



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    #3
    The Continental Op
    Registered Users Posts: 6,921 ✭✭✭The Continental Op


    https://www.boards.ie/discussion/comment/119808870#Comment_119808870

    That whats in the back of my mind ;-) I think I'll probably not bother as its a cheap chinese genny with a fake CE cert.

    Wake me up when it's all over.



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


    Pressing the test button wouldn't confirm correct operation either afaik as it's only operating on the live poles and not the fault path if any

    You would need to simulate a fault



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    #5
    The Continental Op
    Registered Users Posts: 6,921 ✭✭✭The Continental Op


    I'll probably give it a try just need to wait for a bit of better weather to do it as is stored outside.

    Wake me up when it's all over.



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    #6
    iwillhtfu
    Registered Users Posts: 6,372 ✭✭✭iwillhtfu


    https://www.boards.ie/discussion/comment/119808877#Comment_119808877

    Technically its not fake but misleading. Their CE stands for China Export or something along those lines.

    I don't see why you couldn't Install an rcd on it gen sets covering buildings everyday with rcds



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    #7
    kirk.
    Registered Users Posts: 4,957 ✭✭✭kirk.


    https://www.boards.ie/discussion/comment/119809387#Comment_119809387
    https://www.boards.ie/discussion/comment/119809341#Comment_119809341

    Think it's the inverter type the issue is with cos of the earthing setup



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    #8
    kirk.
    Registered Users Posts: 4,957 ✭✭✭kirk.


    Pressing test button conforms that the RCD does indeed work properly

    Then in the event of an insulation fault for example you might find nothing will happen at all as there's no fault path.Cant say I know too much about them always seems such a complex subject generator hookups



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    #9
    10-10-20
    Registered Users Posts: 7,171 ✭✭✭10-10-20


    Isn't part of the issue with cheap gennys that the live and neutral are just 110v AC out of phase by 90 degrees anyway (giving 220v AC when measured), and the synchronisation between both gets thrown by switched loads, causing any RCD to read a delta between the "L" and "N", tripping the RCD...?



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    #10
    kirk.
    Registered Users Posts: 4,957 ✭✭✭kirk.



    I'd say any REC would just just fit a 2 pole changeover and plug and no more

    Whatevers plugged in after that seems to be a minefield

    These are "portable" generators after all designed to supply an item of equipment



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    #11
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,596 Mod ✭✭✭✭2011


    https://www.boards.ie/discussion/comment/119821915#Comment_119821915

    If the two phases were 110V and were 90 degrees apart then the voltage between there would be 156 volts (pythagorean theorem).

    If 90 degrees apart to start with they are out of sync

    The issue with cheap generators is poor voltage regulation and a very ragged waveform.



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    #12
    10-10-20
    Registered Users Posts: 7,171 ✭✭✭10-10-20


    https://www.boards.ie/discussion/comment/119822092#Comment_119822092

    180 degrees then.



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    #13
    monseiur
    Registered Users Posts: 1,253 ✭✭✭monseiur


    Not wishing to hi jack thread and not an a electrician but can I ask a genny related safety question which may very well be a stupid question ! I understand that the earth cable is a critical part of house wiring - I'm curious to find out how a, say, 5KVA portable generator is earthed, in the event of a fault what happens when there's no direct path to earth ?



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    #14
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,596 Mod ✭✭✭✭2011


    https://www.boards.ie/discussion/comment/119822353#Comment_119822353

    Then you have a generator that provides 220 volts between the phases that are 180 degrees apart. This angle will not change regardless of the load. It is fixed due to the placement of the stator coils.

    What can change is the phase angle between the current and the voltage. This will depend on the reactance of the load.



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    #15
    kirk.
    Registered Users Posts: 4,957 ✭✭✭kirk.


    https://www.boards.ie/discussion/comment/119822923#Comment_119822923

    If there's no direct path through a wire or ground through rods nothing happens in a fault situation ,no MCB or RCD trips

    The danger arises when there's 2 faults and they're both accessible, not a very likely scenario



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    #16
    The Continental Op
    Registered Users Posts: 6,921 ✭✭✭The Continental Op


    https://www.boards.ie/discussion/comment/119831564#Comment_119831564

    Not sure what you mean there? If there is no earth and you short out a cable (edit) to earth that is connected to a RCCB then there will be an imbalance in the current between the live and neutral and the RCCB will trip. The reason for me thinking about attaching an RCCB device to my generator.

    Post edited by The Continental Op on

    Wake me up when it's all over.



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    #17
    Bruthal.
    Registered Users Posts: 209 ✭✭Bruthal.


    Many assume any live cable in contact with earth will involve current flow. If you sit a car battery on a table and connect it's positive terminal to the ground, how much current will flow?



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    #18
    The Continental Op
    Registered Users Posts: 6,921 ✭✭✭The Continental Op


    https://www.boards.ie/discussion/comment/119834164#Comment_119834164

    If no current flows your in no danger then.

    Wake me up when it's all over.



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    #19
    kirk.
    Registered Users Posts: 4,957 ✭✭✭kirk.


    https://www.boards.ie/discussion/comment/119834466#Comment_119834466

    2 faults and you could be electrocuted

    You could have 1 fault on pipework a water pump for example and a later fault develops anywhere else on a metal appliance



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    #20
    kirk.
    Registered Users Posts: 4,957 ✭✭✭kirk.


    There's probably less risk now because there's mostly plastic appliances and plastic pipework

    Earthing and protective devices clear faults otherwise there's a hazard

    Can't say I know too much it's a complicated subject earthing and generator hookups



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    #21
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,596 Mod ✭✭✭✭2011


    It is quite common on ships not to have any earth reference



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    #22
    The Continental Op
    Registered Users Posts: 6,921 ✭✭✭The Continental Op


    https://www.boards.ie/discussion/comment/119858121#Comment_119858121

    Why would you bother when the whole metal structure is earthed?

    btw sorry still haven't got around to testing the RCD socket yet :-(

    Wake me up when it's all over.



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    #23
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,596 Mod ✭✭✭✭2011


    https://www.boards.ie/discussion/comment/119858419#Comment_119858419

    To give the electrical system an earth reference.



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