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Earth Rod. Milton Keynes.

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Mr. Nagy again. The area of Milton Keynes he visited is one of the older pars, probably Wolverton, Stony Stratford  or New Bradwell perhaps. Victorian terraces. The supplies there are normally underground P.I.L.C. in most cases. Even if externally surface clipped cables are used as the main supply cables, there should be no reason not to be able to get P.M.E. earthing.


Comments?


Why did he install an earth rod? P.M.E. must be available in the densely populated parts of M.K.


Also a mention of a V.O.E.L.C.B. Note. It was the top terminals that were connected to the mains supply.

https://www.youtube.com/watch?v=G1H5Drf42bA


Z.
  • 0
    Why was the board changed? He showed us the innards of the old one and told us that they were still in good condition.


    He didn't explain the Zs of 1.4 Ω at the hall socket. Could it have been via bonding to gas or water (or both) and thence to a supplier's earth elsewhere in the street?


    We couldn't see the service head so let's assume that the N-E link was open. I wonder whether anybody enquired whether a supplier's earth might have been available. If it had been, it would have avoided that unsightly conduit running up the front wall.


    All a bit odd!
  • 0
    Chris Pearson:

    Why was the board changed? He showed us the innards of the old one and told us that they were still in good condition.


    He didn't explain the Zs of 1.4 Ω at the hall socket. Could it have been via bonding to gas or water (or both) and thence to a supplier's earth elsewhere in the street?


    We couldn't see the service head so let's assume that the N-E link was open. I wonder whether anybody enquired whether a supplier's earth might have been available. If it had been, it would have avoided that unsightly conduit running up the front wall.


    All a bit odd!


    I know the area Chris, and P.M.E. earthing would normally be available.


    Years ago when the houses only had a TT supply I expect that the V.O.E.L.C.B. earth rods would have been installed much too close to underground metal service gas and water pipes, so were not out of the effective resistance areas of such. This would have compromised the safety operation of the V.O.E.L.C.B.s. 


    Even though parallel earth paths existed to the earth rod it was not always the case that danger was present. Crabtree suggested that this may have been a good thing as a, It reduced nuisance tripping of the V.O.E.L.C.B.

    b, It may actually allow the operation of protective devices like fuses or circuit breakers.


    and the V.O.E.L.C.B. would still protect earthed installation metalwork against Voltage up to 50 Volts maximum if the rod was out of the resistance area of parallel earths.


    I expect that water and gas pipe bonding produced his low loop impedance rather than the building fabric.


    Edit. Add. In this area the main fuse is in a separate insulated carrier  sealed with wire, and the neutral block is also in a separate sealed block, Henley block  style. So not both in one cutout head..


    Z.


  • 0
    The other thing that occurred to me was that when he hit an obstruction, he just drilled through it. Presumably not the incoming leccy, gas, or water 'cos we would have known about it, but perhaps the house's main drain?
  • 0
    Chris Pearson:

    The other thing that occurred to me was that when he hit an obstruction, he just drilled through it. Presumably not the incoming leccy, gas, or water 'cos we would have known about it, but perhaps the house's main drain?


    Indeed, underground near to the houses are many, many, buried service pipes and cables. Some areas even have the newfagled cable t.v. and fibre cables.


    Z.


  • 0
    Chris Pearson:

    Why was the board changed? He showed us the innards of the old one and told us that they were still in good condition.

     


     A good question. And why get a London sparks to travel all the way from the big smoke up to the land of roundabouts and concrete cows?


    Some possible reasons.


    1. The owner is a London property investor and wants to rent out the two up, two down M.K. house and wants to cover his position regarding safety.


    2. It may be a financial lender's requirement.


    3. The new owner wants to completely refurbish the property.


    5. The new owner bought the property via an on-line auction sold as unseen.


    6. An "expert" suggested a new consumer unit as there was no earthing present.


    Any others anyone?


    Z.


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