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RCBOs and lighting?

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2

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    #32
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Risteard81 wrote: »
    Technically electrocution means that it is a fatal electric shock. It was originally a contraction of "electrical execution" when the electric chair was invented.

    Invented by a non-REC no doubt


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    #33
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Risteard81 wrote: »

    Non-REC was not being used in a derogatory sense - simply the only factual way to describe the person unknown.

    Would you say it is more likely it would be a superior installation if it was a REC as opposed to a non REC qualified electrician?


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    #34
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    Risteard81 wrote: »
    Technically electrocution means that it is a fatal electric shock.

    Correct.
    This applies whether it is by REC or non-REC :)


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    #35
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Would an electric chair be on an RCD?


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    #36
    Risteard81
    Registered Users Posts: 2,567 ✭✭✭Risteard81


    Bruthal wrote: »
    Would an electric chair be on an RCD?

    It would be irrelevant if no pole of the supply was Earthed.


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    #37
    Fordcspri23
    Banned (with Prison Access) Posts: 60 ✭✭Fordcspri23


    Does 2011 not know that to comply with regulations lighting in certain locations, outdoor at certain heights etc have to go through an rcbo. Also they do not nuisance trip.


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    #38
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    Fordcspri23 wrote: »
    Does 2011 not know that to comply with regulations lighting in certain locations, outdoor at certain heights etc have to go through an rcbo.

    If you were to read this thread you would have the answer.
    Also they do not nuisance trip.

    Are you actually stating that no RCD has ever nuisance tripped?
    So its just an urban myth?


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    #39
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    @ Fordcspri23, a little bit of light reading for you:
    ABB seem to think that nuisance tripping exists. See link


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    #40
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Risteard81 wrote: »
    It would be irrelevant if no pole of the supply was Earthed.

    To help reduce the chance of electrocution though
    Joking here, just in case you think im serious


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    #41
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    Risteard81 wrote: »
    The fault wasn't fixed presumably because no testing was done and the non-REC was unaware of it.

    I doubt that testing would have been necessary to know that something was seriously wrong.
    There were volt drop issues such as dimming with the electric shower running but still none of them clicked what was going on.

    It is amazing that the short survived so long. What caused it? Was it the enclosure?

    I agree that an RCBO would have tripped for this specific fault but so would a double pole MCB which are required by the regulations in some situations. I just feel that although RCDs solve one issue they introduce a different problem.

    What caused the issue with the neutral between the ESB meter and the DB in the first place?


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    #42
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    Bruthal wrote: »
    To help reduce the chance of electrocution though
    Joking here, just in case you think im serious

    Not if it was desensitised first, this could happen if you were electrocuting someone upstream on the same circuit :pac:
    I'm joking too


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    #43
    Fordcspri23
    Banned (with Prison Access) Posts: 60 ✭✭Fordcspri23


    2011 wrote: »
    @ Fordcspri23, a little bit of light reading for you:
    ABB seem to think that nuisance tripping exists.

    In low percentage terms, I will choose not to read the light reading thanks.


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    #44
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    Not if it was desensitised first, this could happen if you were electrocuting someone upstream on the same circuit :pac:
    I'm joking too
    The executioner is probably desensitized anyway.


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    #45
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    Fordcspri23 wrote: »
    In low percentage terms, I will choose not to read the light reading thanks.

    Yes, nobody suggested otherwise.

    In fact RCDs are actually are very rarely needed too when you think about it. The number of times we actually want them to trip (due to a fault) is probably an even a lower percentage.


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    #46
    Risteard81
    Registered Users Posts: 2,567 ✭✭✭Risteard81


    2011 wrote: »
    What caused the issue with the neutral between the ESB meter and the DB in the first place?
    The DB was so full and a bit of a rat's nest that it was difficult to see where it was going. Had floorboards up above that initially with the intention of replacing the meter tails but then managed to get the end of the neutral. Not sure how long it had been like that but there seemed to have been a number of additions and alterations including a supply to a garage (which was now a granny flat with a tenant in it) so I would guess that it happened when that was being done. (The granny flat had its own issues such as a low-level northern-style DB hidden at the back of a press in the kitchen units. Needless to say I was less than impressed with this setup.

    Just a lot of poor work done over probably a substantial period of time. (I think the house was a repossession.) It would be within a mile or so of the border so I suspect had work done on it by people with little or no knowledge of the southern Wiring Rules.

    In the border areas it's not unusual to come across installations in the north butchered with southern components and installations in the south butchered with northern components. It can be quite frustrating and can often lead to dangerous situations.


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    #47
    Tuco88
    Registered Users Posts: 1,051 ✭✭✭Tuco88


    I'd be on the side of dedicated RCBOs for all, thats just my opinion. An RCD covering several circuits its only hassle. Are farms/milking palours all rcds protection now anyway.

    I would think all rcd protection and arc fault protection is the road in the future?


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    #48
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    Tuco88 wrote: »
    I'd be on the side of dedicated RCBOs for all, thats just my opinion.

    I would only have this view if a risk assessment justified it. Do you know of anyone that got a shock from a light? If they did was it of sufficient magnitude to trip an RCD? Probably not.

    What about critical stuff such as comms cabinets, servers, PLCs?
    What about double insulated fixed appliances?

    Also some devices such as nonlinear loads can nuisance trip RCDs even when healthy.
    An RCD covering several circuits its only hassle.

    Agreed.


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    #49
    Risteard81
    Registered Users Posts: 2,567 ✭✭✭Risteard81


    2011 wrote: »
    Do you know of anyone that got a shock from a light? If they did was it of sufficient magnitude to trip an RCD? Probably not.
    Whilst it may not be of sufficient magnitude to trip a 30mA RCD, this is also the case for anything else protected by it. The fact that it's a lighting circuit rather than a socket circuit does not reduce the magnitude of the shock, which is instead to do with Ohm's Law and the impedance through the human body. So a shock from a lighting circuit is every bit as likely or unlikely to trip the RCD as a shock through another type of circuit.


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    #50
    Tuco88
    Registered Users Posts: 1,051 ✭✭✭Tuco88


    2011 wrote: »
    I would only have this view if a risk assessment justified it. Do you know of anyone that got a shock from a light? If they did was it of sufficient magnitude to trip an RCD? Probably not.

    What about critical stuff such as comms cabinets, servers, PLCs?
    What about double insulated fixed appliances?

    Also some devices such as nonlinear loads can nuisance trip RCDs even when healthy.


    I agree, the same for a fire alarm panel, remote i/o panels, BMS, so on.

    I was looking at a domestic view. But a modern milking parlour id imagine would have interesting load characteristics.I cant honestly say whats in a new one. So suppose design and location?

    You could argue the rcd offers a degree of fire protection, which I like the idea in a domestic lighting setup. In a modern house at minimum have dedicated RCBOs on the sockets circuits.


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    #51
    Fordcspri23
    Banned (with Prison Access) Posts: 60 ✭✭Fordcspri23


    Risteard81 wrote: »
    Whilst it may not be of sufficient magnitude to trip a 30mA RCD, this is also the case for anything else protected by it. The fact that it's a lighting circuit rather than a socket circuit does not reduce the magnitude of the shock, which is instead to do with Ohm's Law and the impedance through the human body. So a shock from a lighting circuit is every bit as likely or unlikely to trip the RCD as a shock through another type of circuit.

    +1


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    #52
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Risteard81 wrote: »
    The fact that it's a lighting circuit rather than a socket circuit does not reduce the magnitude of the shock, which is instead to do with Ohm's Law and the impedance through the human body.
    So if a human body has impedance or resistance of 2k ohms, what current will flow?


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    #53
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    Risteard81 wrote: »
    Whilst it may not be of sufficient magnitude to trip a 30mA RCD, this is also the case for anything else protected by it. The fact that it's a lighting circuit rather than a socket circuit does not reduce the magnitude of the shock, which is instead to do with Ohm's Law and the impedance through the human body. So a shock from a lighting circuit is every bit as likely or unlikely to trip the RCD as a shock through another type of circuit.

    Nobody disputes that.
    The difference is the risk profile. This is why the regulations are what they are.

    Once every circuit has RCD protection what next? Lighting protection on every house?
    Rubber mats under the distribution board in the hall?


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    #54
    tomplate
    Closed Accounts Posts: 63 ✭✭tomplate


    It's inevitable that we'll follow the UK and have rcbo for all domestic circuits

    Creeping regulation being what it is


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    #55
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    tomplate wrote: »
    It's inevitable that we'll follow the UK and have rcbo for all domestic circuits

    Creeping regulation being what it is

    It wouldn’t surprise me.

    My point is that it is easy to play the safety card as people are reluctant to argue against it regardless of the logic (or lack thereof) behind the argument.

    As I have said before you only have to look at Safepass as an example of something done in the name of safety that (in the opinion of many) is far more about the protection of vested interests.


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    #56
    tomplate
    Closed Accounts Posts: 63 ✭✭tomplate


    It's a logical progression to bring in the 30mA protection for all circuits

    It covers the bases of fire,fault current and electric shock in a domestic environment.

    It introduces a new maintenance aspect to the installation as they're not 'fit and forget' type devices


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    #57
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    It will be all RCBOs eventually.

    How many lives a year will it save?


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    #58
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    tomplate wrote: »
    It's a logical progression to bring in the 30mA protection for all circuits

    That is an opinion. I’m not suggesting that it is any less valid than opposing opinions but it is an opinion nonetheless.

    Someone else may say 10mA RCDs are the logical progression. I have seen these installed in hospitals on socket circuits. Safer again? Or would it actually make a difference?
    It covers the bases of fire,fault current and electric shock in a domestic environment.

    Only some of them. This goes back to the need for a proper risk assessment.

    For example when an electrical system is risk assessed it may be seen that there is a requirement for many additional safeguards to be put in place to deal with the risks thy you listed. Recently when I attended a risk assessment and it was determined that we needed a VESDA system, arc detection and gas suppression. Ok, this was in an industrial setting, but the same logic applies. The safeguards should reflect the risk.
    It introduces a new maintenance aspect to the installation as they're not 'fit and forget' type devices

    Yes, don’t forget to press your test button!


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    #59
    tomplate
    Closed Accounts Posts: 63 ✭✭tomplate


    Bruthal wrote: »
    It will be all RCBOs eventually.

    How many lives a year will it save?

    I have seen dangerous fault currents on lighting circuits

    Very little in the way of risk from contact though


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    #60
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    tomplate wrote: »
    I have seen dangerous fault currents on lighting circuits

    Very little in the way of risk from contact though

    Presumably an mcb will assist that, unless the non-REC forgets to connect the neutral supply tail while there's a nice little earth neutral fault....

    Overall I'm not heavily against rcd protection on lighting. But shock risk from lights is extremely low. Sockets though, have people plugging all sorts of devices into them and operating them in hand.


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    #61
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    Bruthal wrote: »
    But shock risk from lights is extremely low. Sockets though, have people plugging all sorts of devices into them and operating them in hand.

    +1
    This is exactly what I mean by a different risk profile.


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