TT SYSTEMS - RCDs Ze and Zs. How to make TT systems safe.

TT systems have been around for many years and although TNS and latterly TNCS systems were introduced, there are still many installations around the country that still use TT Earthing Systems.
Perhaps the old adage still applies - if it isn’t broken, then don’t fix it. Indeed, there are occasions when TT Systems may still be installed.
We discuss what a TT system is, why we use RCDs or RCBOs and also discuss Ze and Zs.
We also take a look at R1+R2 in TT systems and how to check that the internal wiring and resistance readings are satisfactory in these installations.
This video is No.68 on our KZbin channel where we have videos on a wide range of electrical topics.
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Always work safely, electricity can be dangerous. If you are unsure, stop and seek advice.