When testing for de-energised you must not just depend on a proximity indicator, but you must make positive/physical contact with your probe/s on the conductor/s. You can use a test lamp, bell or meter and you must check your instrument both before and after to prove de-energised – and before commencing works.
Testing for electrical isolation, or testing for integrity and operability (fault-finding) of energised circuits and equipment of an electrical installation, must be conducted in a safe manner. To meet your obligations under legislation you must have a safe system of work for live testing that includes, as a minimum, all of the following measures:
Preparation:
- Consult with person with management or control of the workplace before commencing, and ensure no adverse impacts
- All live testing must be undertaken by competent persons, i.e.:
a) Qualified licensed electrician
b) Apprentice (year 4) and assessed as competent by supervising licensed electrician and under their direct supervision while working - Use tools, test equipment and PPE that is:
a) suitable, checked & tested and well maintained
b) rated for the application and calibrated (if applicable)
c) used properly
d) PPE that is arc rated to the work task being performed - Complete and work in accordance with well proven Electrical Safe Work Method Statements (SWMS) and relevant SWP.
- Conduct a risk assessment prior to commencement and make sure the SWMS is suitable for the work to be carried out
- Appoint a trained competent Safety Observer – not required if the only testing and risk assessment shows no serious risk
- Ensure isolation point is:
a) clearly marked or labelled
b) unobstructed for easy access and exit
c) capable of being operated quickly
(Note that this is not generally applicable to work on the supply side of main switch)
Getting started:
- Consult with the workers that are involved and those that may be affected
- Prevent unauthorised access to immediate work area
- Keep work area clear of obstructions
- Prevent inadvertent contact with exposed energised components
- Be alert to possible changes to workplace conditions, including:
a) Possible new safety hazards or risks
b) Stop work if unsafe and immediately rectify or notify your supervisor
c) TEST EVERY TIME BEFORE YOU TOUCH
On completion of job:
- Make safe – terminate all conductors before re-energising
- If risk assessment prepared, retained record for 28 days
Where the risk assessment determines the need for the higher level of risk control, the measures as described below should be considered. Such higher risk control measures may for example be appropriate when testing on switchboards or on equipment that have a high potential fault current, or where the equipment is in a poor state of repair. All other live work, independent of equipment condition or rating, you must observe these rules:
Plan the job prior to commencement of work:
- Ensure that the work is permitted and justified under local legislation
- Conduct a risk assessment in respect of the work, and in consultation with the persons proposed to do the work
- There must be a SWMS that applies to the work – no exceptions
- The persons doing the work are appropriately qualified licenced electricians, trained and instructed in safe work practices for the particular task, including the proper use of test equipment, tools, accessories and personal protective equipment
- A safety observer is appointed who is competent in electrical rescue and cardio-pulmonary resuscitation (CPR) and is trained in the activity. Appropriate rescue and first aid equipment must be available at the worksite.
- Consult with the supervisor and senior manager, and the person with management or control of the workplace. They should all be made aware of the task and authorise the work occurring (other than testing). This may be managed via a Permit to Work or “Request to work on live equipment”.
Specific requirements in preparation for the work:
- Appropriate test equipment, tools and accessories should be available for the persons doing the work. Special insulated tools for working on low and high voltage mains or apparatus must first be tested and rated as being safe to use at the required voltage levels. All low voltage rated tools may not be safe at the upper level (up to 1000 Volts AC) of the low voltage range – use Cat 3 or 4 Rated test leads and instruments
- Use suitably insulated tools to minimise the possibility of short circuits
- Appropriate clothing and personal protective equipment for the work must be available for both the persons doing the work and observing (refer section on Arc Flash). Approved type Insulating Gloves must be worn when working on exposed low voltage live circuits and equipment. Such gloves must be air-tested daily prior to use by rolling the gloves from the cuff to force air into the fingers
- Approved Insulating Mats, Shrouds, Hose (Tiger Tails), Insulating Screens or Barriers must be used when working on or adjacent to exposed live circuits and equipment in order to insulate / shield the worker’s body and equipment from Earth and electrical energy. When used, these items shall be securely fixed to prevent their displacement
- Various forms of shielding can be used including Perspex sheeting, insulated mats or plastic sheeting temporally fixed to preclude access and stop objects from falling into the space, including drop zones
- Have an emergency plan and procedures in place
- Work crew to have on hand a fully equipped first aid and rescue kit with medical supplies suitable for the treatment of burns and cardiac arrest (defibrillator)
- The isolation point of the relevant electrical supply must be clearly identified and able to be reached and operated quickly without any need to negotiate or remove obstacles
- The work area is clear of obstruction so as to enable entry and exit quickly and safely. To enable rapid egress in an emergency, switch-room doors and switchyard gates must be opened outwards and chocked in the open position prior to commencing any work
- Unauthorised persons are prevented from entering the work area by signage or barriers, or both
- Consult with the workers and those that might be affected. Instruction is to be given to all workers engaged on the work to enable them to isolate the point of supply should an electric incident occur and follow the correct emergency exit in the event of fusion.
Whilst undertaking the work:
- Clothing and personal protective equipment for the work must be properly worn and used
- Insulation gloves (appropriate type for electrical works only) are to be worn by all workers engaged in the work
- Insulation mats are to be installed to isolate workers from earth situations
- Test equipment, tools and accessories must be well maintained and properly used
- Do the work in accordance with the SWMS, risk assessment and any other instructions – if a difference occurs stop work and review procedures for additional hazards and implement appropriate additional controls
- Maintain situational awareness regarding changes to workplace conditions, including possible new safety hazards
- Stop work if unsafe and immediately rectify or notify your supervisor
- TEST EVERY TIME BEFORE YOU TOUCH
- The Safety Observer will watch and endeavor to warn the operative or call to safely stop work if there is danger of injury. The observer will assist in rescue and first aid where necessary.
On completion of job:
- Make safe – terminate conductors before re-energising.
- Return a copy of the documentation prepared for the work task to the office/base to be retained for records
- Ensure any Permits are completed and signed off before work task is closed.
Remember:
There is a prohibition on live work unless specific criteria have been observed and met. Make sure the proposed work is permitted under safety and electrical legislation and ensure that you confirm all rules associated with energised electrical work with your employer before any commencement of the work task.