http://www.electricalsafetyfirst.org.uk/guides-and-advice/electrical-items/rcds-explained/
Now that I read what a RCD is and your comment about people walking through your show I appreciate why you have these. In Canada I'll have to check to see if they are required by law. I do not invite anyone on my property, have ground fault circuits and generally believe I have protected including trip hazards for the most part , but I can really see the benefit for RCDs.
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