thanks all, got a few things to get on with there, bit of the Sherlock to do. Hope I can get some answers, thanks again. 
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- Thread starter Liamondo
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thanks all, got a few things to get on with there, bit of the Sherlock to do. Hope I can get some answers, thanks again. Sponsored Links
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The upshot is, if you have a TT supply, either overhead from a pole or from next door, or subterranean, and you have a 30mA RCD protecting the supply, you should be safe (assuming of course the RCD is operating correctly).
A correctly installed TT supply (either overhead or underground) can be identified by the lack of an earth connection to the incoming cable and the presence of an external connection with literal earth, perhaps a rod or other electrode.
The other possibility is that you have an earth connection to your supply cable, but the connection is poor.
The earth loop impedance measured at your intake is known as Ze (e for external) and as Jaymack says, the maximum Ze at the intake is 0.8 ohms for TN-S and 0.35 ohms for TN-C-S (sometimes known as PME).
If your Ze is poor and you have PME or TN-S, then the DNO is responsible for its upkeep.
See here for diagrammatical explanation of supply types://www.diynot.com/wiki/electrics:earthing_supply_types_and_bonding:earthing_arrangements
A correctly installed TT supply (either overhead or underground) can be identified by the lack of an earth connection to the incoming cable and the presence of an external connection with literal earth, perhaps a rod or other electrode.
The other possibility is that you have an earth connection to your supply cable, but the connection is poor.
The earth loop impedance measured at your intake is known as Ze (e for external) and as Jaymack says, the maximum Ze at the intake is 0.8 ohms for TN-S and 0.35 ohms for TN-C-S (sometimes known as PME).
If your Ze is poor and you have PME or TN-S, then the DNO is responsible for its upkeep.
See here for diagrammatical explanation of supply types://www.diynot.com/wiki/electrics:earthing_supply_types_and_bonding:earthing_arrangements
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