What is a Residual Current Device (RCD)? and how do they work?

Residual Current Devices, or RCDs, are an essential form of protection for most circuits in modern electrical installations. In this video, we explain how an RCD works and the protection they offer to electrical installations and the people who use them.

http://hub.efixx.co.uk/SE-cprotection

=========================================
00:00 Schneider circuit protection series
00:20 What is a residual current device (RCD)?
00:50 What protection does an RCD provide?
02:06 Electric shock protection
03:20 How does an RCD work?
04:30 Where are RCDs used?
04:50 Fault protection with RCDs
06:30 Using RCDs with TT earthing systems
07:50 RCBOs
09:29 Different types of RCD - AC, A, B, F
10:16 Special electrical locations
=======================================