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Discuss Maximum Disconnection Times in the UK Electrical Forum area at ElectriciansForums.net

Good solid copper connections , without reliance on -expensive -Historic lead - Greyness !
(we have fracking -greed to worry about - too !)
(admittedly -my opinions are more from an interested engineer-Than full spec Spark)
 
I'll ask this: how did loop impedance become a thing in the UK? Was it actual shocking electrics or a theoretical perspective of "what if"?

Loop impedance has always existed, its a property of any electrical supply, its the knowledge, awareness and testing etc which has developed over time.

UK wiring regulations have required testing of, and specified maximum impedances of, earth's for a very long time.
And as the knowledge of the science has improved then so have the requirements, also the ability to test these things has developed allowing them to be tested.

If I recall correctly early versions of the regulations describe test methods which require the electrician to connect a power source of specified capacity and take voltage and current measurements to establish earth impedances.

I've I get chance I'll post some relevant pages from old regs books later.
 
Is a low earth impedance necessary on TN-C-S and TN-S?

What exactly did you mean when you asked if it's necessary to test the earth rods on TN systems?
I assumed you meant the earth electrodes at the transformer for the N-E link at source and/or the other TNCS electrodes used along the distributing mains.
 
What exactly did you mean when you asked if it's necessary to test the earth rods on TN systems?
I assumed you meant the earth electrodes at the transformer for the N-E link at source and/or the other TNCS electrodes used along the distributing mains.


Do you have earth rods at the service on a TN-C-S or TN-S system?
 

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