Rcd use in workshop

[Brian WoodParticipant @brianwood45127]

Hello Les,

Imagine if you will my house supply is an island, fed by power from the street cable. 8 different ways in the house are served from the consumer unit, all protected by one residual current device. One of those ways runs the whole length of the house and out to the workshop.

Now imagine that my electrician created a new island on the end of that cable run with a new residual current device, using its own earthing rod at the remote end. The earth conductor in the long cable back to the consumer unit has been disconnected at the new RCD and the cable run out to the workshop from thaty device is coupled into that RCD instead of the house RCD.

Both 'islands' are fully earth leakage protected but the actual potential on the house earth and workshop earth may be different, as each is referenced to the earthing rod at the two ends. My electrician said it was unconventional, but completely safe and many would argue at the logic.

Brian

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