Document ID: chunk:federal_register_of_legislation:F2016L00407:body:0:p49
Version: federal_register_of_legislation:F2016L00407
Segment Type: other
Provision Reference: 
Character Range: 134403–139499

(CMEN) area, even when working on high-voltage, contact between the earthed connector and a low-voltage phase can cause an electric shock.
Working                                                             Arcs, explosions and electrical faults can cause burns. Workers should be protected from the effects of burns. Examples include:
near sources                                                            * materials providing a conductive path between sources of potential,
of arcing, explosion                                                      for example uninsulated tools falling across busbars
or fires                                                                * abnormal conditions on circuits such as:
                                                                              + lightning striking mains
                                                                              + circuits of different voltages touching each other e.g. high-voltage contacting low-voltage circuits
                                                                              + high voltage in the secondary circuit of a current transformer if an open circuit occurs when current is flowing in the primary circuit.
                                                                        * abnormally high voltages when synchronising different supplies. For example, if the waveforms are 180° out of phase, twice the peak-to-peak voltage may be imposed
                                                                        * voltage multiplication effects, including:
                                                                              + ferro-resonance where the capacitive and inductive components
                                                                                of underground cables and transformers can significantly increase voltages when single-phasing occurs
                                                                              + re-strike can occur if capacitors are energised, de-energised and
                                                                                re-energised in rapid succession
                                                                        * leakage or electrical discharge causing insulation to be compromised, for example a combination of a build-up of contaminants on insulators, wet weather or tracking through air voids in pitch filled insulating chambers
                                                                        * failure of insulating mediums.
Working                                                             After faults and fires, often in emergencies, electrical workers may be exposed to unsafe atmospheres. Toxic gases and lack of oxygen can cause illness and death. General workplace health and safety risk control measures should be used in these situations.
in unsafe atmospheres                                               The method of extinguishing fires should be addressed. Typically, carbon dioxide or powder type devices are used against electrical fires. Extinguishers including water, foam and wet chemical should not be used as they significantly increase the risk of electric shock.

Modifying                                                               * Electrical drawings/tables not reflecting 'as installed' installations.
or repairing existing low-voltage electrical installations              * More than one source of supply or energised circuit may be available
                                                                          on the premises or at the equipment.
                                                                        * The supply becoming energised during the work.
                                                                        * Automatic starting of machinery after supply is restored.
                                                                        * Managing metallic shavings (swarf) ingress into conductive parts of equipment.
                                                                        * A conductor considered to be de-energised was found to be energised.
                                                                        * Old installations (where several modifications may have been made, circuits have not been identified, or the insulation has deteriorated).
                                                                        * Voltages on disconnected conductors, particularly neutrals.
                                                                        * Installations where the MEN system is used, the rise in the earth potential due to a high impedance return path to the distribution neutral.
                                                                        * Lack of information about isolation, sources of supply or the location
                                                                          of electrical conductors.
                                                                        * Lack of clear safe access to locate electric