High Voltage Safety
An authorized user of the laboratory will normally hold a B.E degree or have a form of electrical registration. Such a person will be expected to demonstrate an understanding of preferred practices and operation of equipment, and will assume responsibility for the safe operation of equipment and the safety of personnel in the area under use. An authorized user shall hold a current First Aid Certificate.
The laboratory has a local earth mat located outside the north wall of the building. There are a number of available connection points to this earth. There are also earth connections from the in-coming power supply from the sub-station located in the south-east corner, level 1 of the Engineering Faculty core block. These earths are regarded as permanent earths.
Any equipment required to have a permanent earth must have a connection which requires mechanical assistance to remove. Such equipment must not have temporary earths, which are earth connections which can be removed by hand. Disconnection of a permanent earth, if required, is to be undertaken by staff only.
The outputs of permanent fixed high voltage equipment are required to be temporarily earthed when not in use. Any modification to the structure of this equipment should only be undertaken when isolated from permanent supplies.
Any equipment to be energized must have all exposed metal connected to earth unless this metal forms part of the energized circuit.
Any potentially live part of equipment under test and HV supply outputs will be earthed with temporary earths before personnel touch the equipment.
Equipment not in use but in proximity to equipment that is live, should be treated as live due to electromagnetic induction. Exposed metal parts on this equipment should be earthed before touching.
Capacitors not in use should have their terminals connected by metallic wire to avoid charging.
Equipment is to be energized only by or under the direct supervision of an authorized user. The authorized user shall, at least, visually check the equipment to ensure correct operation and safety before it is energized. No unauthorised user is to do any practical work using live equipment, whilst alone in the laboratory.
When equipment is to be energized, all personnel are to be outside the test enclosure except when demonstrations, research or laboratories require personnel to interact with energized equipment. Movement inside the test enclosure is only permitted under the strict direction of an authorized user.
Gate interlocks, where affixed, are not to be regarded as the only means of providing safety. The area being used during testing should be defined from the rest of the laboratory in such a way that persons working outside the testing area are not in danger. Where more than one set of high voltage equipment is in use at the same time, the areas required for each task are to be clearly defined. Practical steps such as barriers and signs should be used in a manner that allows an experiment or demonstration to be carried out safely.
Gate interlocks, barriers and signs are not to be regarded nor relied on as a fool proof system to ensure safety. It is the responsibility of the operator and safety observer to ensure safe operating practice.
No HV supply equipment will be modified unless undertaken by an authorized user or under the direction of an authorized user.
Flashovers can be noisy. Consideration and warning should be given to other laboratory users. Where a noisy flashover is anticipated, it is recommended that ear-muffs be used to prevent ear damage. Where insufficient earmuffs are available for the number of people present, the operator should advise of the potential noise and recommend the placement of hands over ears.
Flashovers can be a source of electromagnetic interference. Equipment susceptible to this interference should be shielded. Consideration of the effect of any experiment should be given to other High Voltage laboratory users and appropriate action taken to reduce or eliminate electromagnetic interference.