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50A supply

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    #32
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    Bruthal wrote: »
    I think you miss the point of bonding, judging by that.

    Do you feel that a hotpress needs to be bonded if an electrical component gets added to it? Just for clarity the house is plumbed in plastic pipe, 100% visible.


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


    Sir Arthur Daley wrote: »
    Do you feel that a hotpress needs to be bonded if an electrical component gets added to it? Just for clarity the house is plumbed in plastic pipe, 100% visible.

    If the cylinder is connected to nothing only qualpex, no bonding is needed. Don't think I seen one yet that was exclusively qualpex.


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    #34
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    Bruthal wrote: »
    If the cylinder is connected to nothing only qualpex, no bonding is needed.

    Not alone is it not needed it should not be introduced, by doing so you are introducing a path by which an electrical charge could become present on metal, which, in the absence of the earth conductor, would have no possible means of generating or becoming charged with voltage.


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


    Sir Arthur Daley wrote: »
    Not alone is it not needed it should not be introduced, by doing so you are introducing a path by which an electrical charge could become present on metal, which, in the absence of the earth conductor, would have no possible means of generating or becoming charged with voltage.

    In what circumstances would it become "charged" with voltage?


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    #36
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    Bruthal wrote: »
    In what circumstances would it become "charged" with voltage?

    Bad use of wording, presence of voltage.


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    #37
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Sir Arthur Daley wrote: »
    Bad use of wording, presence of voltage.

    Well I knew what you meant, but what circumstances will lead to that?


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    #38
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    Bruthal wrote: »
    Well I knew what you meant, but what circumstances will lead to that?

    If you had it bonded, like you said earlier if the earth potential rises.


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    #39
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Sir Arthur Daley wrote: »
    If you had it bonded, like you said earlier if the earth potential rises.

    And where is this voltage going to be perceived, what points of contact? Just curious now. Consider that every bonded item in the house is now at equal voltage.


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    #40
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    Bruthal wrote: »
    And where is this voltage going to be perceived, what points of contact? Just curious now. Consider that every bonded item in the house is now at equal voltage.

    Bonded items should not have a presence of voltage if the installation is 100% correct.


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    #41
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Sir Arthur Daley wrote: »
    Bonded items should not have a presence of voltage if the installation is 100% correct.

    A failed neutral at a mini pillar would disagree with you there.


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    #42
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    Bruthal wrote: »
    A failed neutral at a mini pillar would disagree with you there.

    The incoming neutral failing you mean?


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    #43
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Sir Arthur Daley wrote: »
    The incoming neutral failing you mean?

    Main neutral to mini pillar bar fails, we now have several houses with 3 phases but no neutral, like an imbalanced load.

    Or, neural to one house fails before neutralising point.

    So now we have voltage on bonded items in a perfectly wired installation.


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    #44
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    Bruthal wrote: »

    So now we have voltage on bonded items in a perfectly wired installation.

    If nothing was on in the house we dont.


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    #45
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    An unrealistic scenario. And with the neutral failure to several houses, nothing on in a house won't mean 0v on it's neutral/earth.


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    #46
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,594 Mod ✭✭✭✭2011


    Sir Arthur Daley wrote: »
    Not alone is it not needed it should not be introduced, by doing so you are introducing a path by which an electrical charge could become present on metal, which, in the absence of the earth conductor, would have no possible means of generating or becoming charged with voltage.

    I know that you are referring to a small domestic installation and you are stating what the regulations are.

    However this is not something that those of us that work in large electrical installations would normally see. When it comes to industrial installations standard procedure is to bond anything that is metal. This even applies to large conductive parts that are bolted together such as structural steel, ductwork, pipework, metal stairs, reenforced steel bars etc..


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    #47
    tomdempsey200
    Registered Users Posts: 1,890 ✭✭✭tomdempsey200


    I saw over on the UK forums that the structural steel can be used as a main bonding conductor

    after it has been bonded itself

    not sure if it's allowed here


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    #48
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    2011 wrote: »
    When it comes to industrial installations standard procedure is to bond anything that is metal. This even applies to large conductive parts that are bolted together such as structural steel, ductwork, pipework, metal stairs, reenforced steel bars etc..

    Lets take a metal stairs in an industrial unit, in you opinion is it better or worse being bonded, im not knocking the procedure or practice just curious of your opinion.


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    #49
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,594 Mod ✭✭✭✭2011


    Sir Arthur Daley wrote: »
    Lets take a metal stairs in an industrial unit, in you opinion is it better or worse being bonded, im not knocking the procedure or practice just curious of your opinion.

    Better for a number of reasons. This would include reducing the likelihood of "flashover" should there be a lightning strike. Better is not just my opinion, it is the opinion of a team of engineers that issued drawings and a detailed scope of work documentation specifically on the earthing and bonding of a large project that I was involved with.


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    #50
    Sir Arthur Daley
    Closed Accounts Posts: 6,720 ✭✭✭Sir Arthur Daley


    2011 wrote: »
    Better for a number of reasons. This would include reducing the likelihood of "flashover" should there be a lightning strike.

    You would be referring to an external stairs here though?


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    #51
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,594 Mod ✭✭✭✭2011


    Sir Arthur Daley wrote: »
    You would be referring to an external stairs here though?

    Internal and external.
    I will try to get you some photos.


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    #52
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,594 Mod ✭✭✭✭2011


    Suppose lightning strikes a building. Ideally the lightning flows from the air terminations, through the down conductors and dissipates through the ground. In a perfect world the lightning protection system would carry all of the current from the strike. We try to achieve this by having very low resistance paths to earth via down conductors.

    If extraneous conductive parts at a different potential are within close proximity to the down conductors there is a risk of flash over. This risk is mitigated by installing inordinate amounts of equipotential bonding. There are different "schools of thought" about how the lightning protection system is tied into the bonding system. I had an interesting discussion with someone that would be considered an authority on this today.

    In reality the potential of the earthing system throughout the building will rise due to a strike. Other methods are used to limit the damage that this will cause.


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