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Exported PME to steel floodlight columns, public tennis courts

Hi

We're doing an EICR at a local tennis club. It has a number of  3 phase floodlights mounted on galavanised columns illuminatimg outdoor tennis courts.

They are earthed via an exported PME TNCS system which was surprising because we'd imagined they would have sunk an earth rod at each column and not exported the PME.

The location is open to the public. Circuits not 30mA RCD protected foir additional protection.

I'm no

Many Thanks for your help

Parents
  •   

    the extract reads as it is good practice to install the additional earth rods for a TN-S lighting circuit being supplied from a TN-C-S supply, if and how you write a recommendation into an EICR is a matter for debate as there’s a “should” and a “good practice” mentioned.

    ”2.5.3 Lighting authority/asset owner private cable distribution system
    A lighting authority/asset owner may design and install their own cable networks but these usually consist of a separate neutral and earth (TN-S), which is connected to a PME point of supply.
    An earth electrode SHOULD be installed and connected to the earth terminal at the point of supply. It is GOOD PRACTICE to install and connect an earth electrode at the last or penultimate lighting column on the circuit where there are three or more columns on that circuit.”

Reply
  •   

    the extract reads as it is good practice to install the additional earth rods for a TN-S lighting circuit being supplied from a TN-C-S supply, if and how you write a recommendation into an EICR is a matter for debate as there’s a “should” and a “good practice” mentioned.

    ”2.5.3 Lighting authority/asset owner private cable distribution system
    A lighting authority/asset owner may design and install their own cable networks but these usually consist of a separate neutral and earth (TN-S), which is connected to a PME point of supply.
    An earth electrode SHOULD be installed and connected to the earth terminal at the point of supply. It is GOOD PRACTICE to install and connect an earth electrode at the last or penultimate lighting column on the circuit where there are three or more columns on that circuit.”

Children
  • True, but if the hundreds of amps was actually in the form of lots of floodlights each with a 20 ohm electrode,

    Doesn't seem likely in the OP's case though - we're told it's a "local tennis club" - so I'm guessing there's a club house, changing rooms, showers, bar etc. and the floodlights have been tagged onto the main installation rather than receiving their own DNO supply. If that is thee case then while the floodlights might appear superficially to be similar to street lighting, in terms of sensible earthing precautions they're in a different ball park,

       -  Andy.

  • Different ball park?

    The guy in the news report linked to above died in a ball park with lights on high columns.

    Yes, in that instance lack of maintenance appears to have been an issue and in the pub garden substandard installation was an issue, but the Wiring Regulations have been revised since these incidents, partly due to what happened.

  • Do we have any idea what went wrong?

    Might it have been a fault which was not cleared by ADS? A faulty RCD?