Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Earth Rod

Options
2»

Comments

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


    M cebee wrote: »
    hmm!
    1666 by 0.03=50v
    Ensures a touch voltage exceeding 50v can't persist(rules speak) for 30ma protected TT does it not

    It does. But in reality, a touch voltage more than a few volts probably wont persist unless the earth rod is hammered into very poor ground.

    My point about the 6k ohm fault is that it would have to be that high an inpedance in the 230v fault to metal to produce 50v with a 1666 ohm earth rod.

    A person touching the metal with 50v touch voltage on it in such circumstances, if they are making a good connection from it to earth, that will lower the touch voltage when it is brought about with such high impedance`s.


  • Options
    #33
    Bozo Skeleton
    Registered Users Posts: 749 ✭✭✭Bozo Skeleton


    Diggerdunne wrote: »
    yeah i am in the process of installing an earth rod...

    Where does one buy an earth rod? I need to earth a kiln. I'm in Dublin 8. I tried Chadwick's on Thomas Street, they said try Charlie Shiels Wholesale in Inchicore, no joy there either, they said try DPL, again no joy, and they told me they didn't know where I'd get one. Google is not being much help. Any one know where I can buy one?


  • Options
    #34
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,593 Mod ✭✭✭✭2011


    The installation where the kiln is installed may already have an earth rod. I would think that you need to connect the kiln to the main earth bar, but it is hard to know from the information provided.


  • Options
    #35
    Bozo Skeleton
    Registered Users Posts: 749 ✭✭✭Bozo Skeleton


    The kiln is installed in a shed in the garden, with a concrete floor. There's power cabling running from the house to the shed. What's happening is the kiln is earthing itself out, so it's switching off before it reaches the required temperature. I've been told this is common with kilns, and that the solution to this is to earth it.
    My knowledge of electricity and domestic electrics is rather limited, I would be getting an electrician to do the job, unless it's a simple enough procedure.
    Thanks for the reply. I've had one problem after another since I bought the thing, hopefully earthing it will finally have it up and running.


  • Options
    #36
    M cebee
    Closed Accounts Posts: 4,431 ✭✭✭M cebee


    Bozo Skeleton wrote: »
    The kiln is installed in a shed in the garden, with a concrete floor. There's power cabling running from the house to the shed. What's happening is the kiln is earthing itself out, so it's switching off before it reaches the required temperature. I've been told this is common with kilns, and that the solution to this is to earth it.
    My knowledge of electricity and domestic electrics is rather limited, I would be getting an electrician to do the job, unless it's a simple enough procedure.
    Thanks for the reply. I've had one problem after another since I bought the thing, hopefully earthing it will finally have it up and running.
    what's happening with it?


  • Advertisement
  • Options
    #37
    Bozo Skeleton
    Registered Users Posts: 749 ✭✭✭Bozo Skeleton


    It's basically cutting out before it reaches it's required temperature. A separate fuse box was installed in the house for it, so it's designed to trip out if, for example the electric shower is being used at the same time. The earth switch on this box trips out and the power goes. I had an email exchange with a guy who makes kilns, he said this is a common occurrence with kilns, and it needs to be permanently earthed.
    The elements in the kiln are working fine, I've had it serviced, so that's not the problem.
    Edit. The way the power connection is installed is, it's just the electric shower being used that will trip the power out in the kiln. The electrician was worried that both being used at the same time could blow the ESB fuse. But the shower hasn't been used when the kiln has been running.


  • Options
    #38
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Earthing the kiln directly wont fix that problem. It is leakage current to the earth conductors from the kiln, by its nature, that causes RCD`s to trip.

    It will need to be connected to an isolator so its hard wired as a fixed appliance, and have no RCD on the circuit to avoid them nuisance trips.

    Does the kiln have its own dedicated circuit from the house?
    Edit: I see it looks like it has


  • Options
    #39
    M cebee
    Closed Accounts Posts: 4,431 ✭✭✭M cebee


    yes it sounds like the kiln and shower are connected to a priority/non-priority unit which is fine except the kiln isn't suitable for 30ma protection
    and doesn't require it
    so you.ll prob have to reconfigure the wiring


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


    Yea maybe a seperate RCD on the outgoing supply to the shower from the priority unit would do the job, and an MCB supplying the priority setup.


  • Options
    #41
    M cebee
    Closed Accounts Posts: 4,431 ✭✭✭M cebee


    robbie7730 wrote: »
    Yea maybe a seperate RCD on the outgoing supply to the shower from the priority unit would do the job, and an MCB supplying the priority setup.
    ya he'll prob need an an electrician to rejig the controller wiring and prob add an mcb for the kiln
    -depending on the exact setup he has now


  • Advertisement
  • Options
    #42
    Bozo Skeleton
    Registered Users Posts: 749 ✭✭✭Bozo Skeleton


    Thanks guys for the help, I appreciate it. I'm not out there at the moment, I'll go out and have a look at what the exact set up is and maybe come back on here with a more detailed explanation of what the situation is.


  • Options
    #43
    Frere Jacques
    Registered Users Posts: 206 ✭✭Frere Jacques


    Not wanting to re open old arguments buuuuuutt....
    I live in one of those 1970s built estate houses and had an electrician in recently to wire up my gas boiler. He gave the house the quick once over and said firstly there was no bonding so I fell in with him and we did that. He said the only other thing he wasn't happy with was that he couldn't see any earth wire and it would be no harm to sink an earth rod and run some 10 square cable to it.
    So I chased out a square hole for an inspection box, made a fitting for the end of my SDS hammer drill and hammered in a 4ft lenght of earth rod. My question is though, where do I connect the other end too. My plan was to turn off the mains at the old bakalite trip switch and then fit it to the earth busbar in the consumer unit. One of the lads at work was wary though. He felt that that was fine for an old once off house which probably had an earth rod sunk somewhere long ago, but he felt if the ESB had earthed along the neutral for say 10 houses, then if something happened to that earth, then my earthrod would become the only conduit to earth of the whole ten houses. Can anyone tell me if this is a valid concern or as previously mentioned in this thread, regardless of the effectiveness of an earth rod, they certainly won't do any harm?
    So yeah, in a nut shell can I tie into my earth bar in a consumer unit with an earth rod?
    Obviously i know advice is only advice and any work is undertaken at my own risk.


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


    Frere Jacques wrote: »
    Not wanting to re open old arguments buuuuuutt....
    I live in one of those 1970s built estate houses and had an electrician in recently to wire up my gas boiler. He gave the house the quick once over and said firstly there was no bonding so I fell in with him and we did that. He said the only other thing he wasn't happy with was that he couldn't see any earth wire and it would be no harm to sink an earth rod and run some 10 square cable to it.
    So I chased out a square hole for an inspection box, made a fitting for the end of my SDS hammer drill and hammered in a 4ft lenght of earth rod. My question is though, where do I connect the other end too. My plan was to turn off the mains at the old bakalite trip switch and then fit it to the earth busbar in the consumer unit. One of the lads at work was wary though. He felt that that was fine for an old once off house which probably had an earth rod sunk somewhere long ago, but he felt if the ESB had earthed along the neutral for say 10 houses, then if something happened to that earth, then my earthrod would become the only conduit to earth of the whole ten houses. Can anyone tell me if this is a valid concern or as previously mentioned in this thread, regardless of the effectiveness of an earth rod, they certainly won't do any harm?
    So yeah, in a nut shell can I tie into my earth bar in a consumer unit with an earth rod?
    Obviously i know advice is only advice and any work is undertaken at my own risk.

    It is not a valid concern. If 230v is connected direct from the main esb transformer to a single earth rod, only a relatively small current will flow. And the return from a few houses down a single earth rod, cant be any higher a current flow than the earth rod direct connected to 230v supply.

    This idea that the load of 10 houses will be forced down a single earth rod is mythical, like many things in electrical.


  • Options
    #45
    Frere Jacques
    Registered Users Posts: 206 ✭✭Frere Jacques


    Thanks Robbie. While you are there, do ye guys use any special lugs at the end of a 10 square wire or is it a case of just strip it back, pop it into an empty clamp next to the other earth wires coming from the mcbs and tighten it up?


  • Options
    #46
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Frere Jacques wrote: »
    Thanks Robbie. While you are there, do ye guys use any special lugs at the end of a 10 square wire or is it a case of just strip it back, pop it into an empty clamp next to the other earth wires coming from the mcbs and tighten it up?

    At the earth rod end there will be a U bolt used, with 2 nuts. I usually fold the stripped earth so it has double the contact area or more, or sometimes fold twice so it has 3 times the area gripped by the clamp. Then use denzo tape on it to protect from moisture.

    At the board end, its an earth bar with screw terminals that will accommodate the 10 square earth. Just strip back enough to go through the earth bar and tighten. Sometimes its a clamp on the earth bar for main earths.

    Take a photo of the board with cover removed and someone will advise, and that advice may be to get in an electrician, which is always good advice.


  • Options
    #47
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,593 Mod ✭✭✭✭2011


    Good advice from Robbie.

    I think that the best move now is to get a registered electrical contractor in to advise, this is going beyond DIY. The chances are that this installation should be neutralised, this needs to be checked too.


  • Options
    #48
    Frere Jacques
    Registered Users Posts: 206 ✭✭Frere Jacques


    Wise words 2011.
    I have the clamp and the Denso tape for the lower section Robbie and have conduit running up to the CU and a hole drilled in the base of this. Have had the CU checked and all is good so will just go into the earth rail. I know enough not to fry myself and am happy enough with the rest of the safety aspect.
    Thanks to both of you for the input. Robbie, regarding the input from the lad at work I think he was worried that a voltage could be present on my bonded pipes if the ESB ground failed and there was a PD between something in a neighbours house and mine due to a fault I knew nothing about.
    Anyway as I said, thanks to both of you for the help. I know this is a tricky matter where a little information in the wrong hands can lead to a potentially fatal outcome.


  • Options
    #49
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Frere Jacques wrote: »
    Robbie, regarding the input from the lad at work I think he was worried that a voltage could be present on my bonded pipes if the ESB ground failed and there was a PD between something in a neighbours house and mine due to a fault I knew nothing about.

    That happens when the esb neutral fails outside the house, and is a problem with neutralised installations (since the earthing in the house is now connected to a broken neutral), which is the setup in the vast majority of houses in Ireland, and would happen whether or not the house has its own earth rod. The earth rod will reduce the touch voltage somewhat, although not usually by much. But having the earth rod wont add to the problem.

    Ensuring everything is bonded within the house helps prevent potential differences in such cases, and so minimises shock risk.


Advertisement