Operation Totem Operation Totem Operation Totem was a pair of British atmospheric nuclear tests which took place at Emu Field in South Australia on 15 October 1953. They followed the Operation Hurricane test of the first British atomic bomb, which had taken place at the Montebello Islands a year previously. The main purpose of the trial was to determine the acceptable limit on the amount of plutonium-240 which could be present in a bomb. In addition to the two main tests, there was a series of five subcritical tests. These did not produce nuclear explosions, but used conventional explosives, polonium-210, beryllium and
Residual-current device to the appliance. The test button (8) allows the correct operation of the device to be verified by passing a small current through the orange test wire (9). This simulates a fault by creating an imbalance in the sense coil. If the RCD does not trip when this button is pressed, then the device must be replaced. Residual-current and overcurrent protection may be combined in one device for installation into the service panel; this device is known as a GFCI (ground fault circuit interrupter) breaker in the USA and Canada, and as an RCBO (residual-current circuit breaker with overload protection)