An old and obsolete voltage operated earth leakage circuit breaker.

These were used on TT installations in the 1970s and earlier to disconnect the supply if a fault occurred between live and an earthed metal part of the installation.

These devices are NOT RCDs, and do not provide any protection against electric shock.

The principle is that they are tripped by a voltage between the earth electrode for the installation and the earth connection to exposed conductive parts within the installation.

The wiring attached to this is tinned copper, and not aluminium. Aluminium wiring in small sizes was only in use for a very short period and was copper clad. 99% or more of wiring with a silver appearance is tinned copper.

00:00 Introduction
01:00 The Item
02:58 Inside
05:17 Trip coil
06:55 Buttons
08:45 Trip using DC voltage
11:49 Tinned copper wiring
14:54 TFW