Electrical shock hazards in ceiling spaces
In most buildings, especially houses, much of the building’s electrical wiring for lights, socket-outlets, air-conditioning and other electrical equipment is run (or partly run) through the ceiling space.
When employees have to enter ceiling spaces to install, repair or do maintenance work, this increases the risk of electric shock. Many people have been electrocuted inside ceiling spaces.
Causes of electrical shock hazards
The following hazards can cause electric shock:
Worn electrical wiring insulation
Electrical wiring insulation which has deteriorated or been exposed to excessive heat can make the insulation become brittle. This can cause the insulation to break into pieces when disturbed, exposing the live conductors.
Vermin can cause damage to electrical wiring by chewing insulation, exposing the live conductors.
Damage to the earth conductor
Hazards can be introduced from damage to the main earth conductor or earth electrode and from the main neutral faults. This may cause current to flow in the earth conductors or metallic parts.
Previous electrical work
- illegal or sub-standard electrical work on the electrical installation
- older properties where lower standards applied to previous electrical work (For example, lights that were not required to be earthed)
Other electrical work completed in the ceiling like air-conditioning or television cable installation may present electric shock hazards.
Consider if the premises has other energy sources such as solar panels as well as solar battery storage. Think about whether they pose a risk to workers working in the ceiling.
Controlling risk of electric shock
An employer or self-employed person must, so far as is reasonably practicable, eliminate any risk associated with construction work. If it is not reasonably practicable to eliminate all or part of the risk then it must be reduced so far as is reasonably practicable.
In the past, mains electricity was required to supply power for work lights and for any power tools that had to be used in the ceiling space. However, with the introduction of a broad range of battery power tools, it is no longer necessary to have mains electricity on when accessing or working in ceiling spaces.
Turn power off at the switchboard
It is possible to eliminate part of the risk by turning the main switch/es off at the switchboard. Electric hot water may have a separate hot water main switch which should also be turned off.
For circuit breaker type switchboards (especial in dwellings), turn off all the circuit breakers to ensure that all mains switches are turned off.
Once the main switches are off, further reduce the risk by ensuring that the switches are locked out if possible, or if not taped over.
Attach a warning sign to the switchboard
Attach a sign to the switchboard that clearly warns against turning the power on.
Signs can be printed or hand written—but must be easy to read.
An example of a sign could be “Danger! Working in ceiling. Do not turn power on”.
Residual Current Devices
Residual current devices (RCDs) should not be relied on to control the risk of electric shock in ceiling spaces. RCDs do not eliminate electric shock risks—they only reduce the risk of the shock being fatal. It is likely that not all wiring in the ceiling space will be protected by RCDs. Also, RCDs will only function in specific electric shock situations.
Safe Work Method Statements (SWMS)
Electrical installation work is construction work unless it only involves routine or minor testing, maintenance or repair work.
Any construction work on or near an energised electrical installation is considered High Risk Construction Work (HRCW). A SWMS must be prepared for HRCW before the work starts, and followed while the work is undertaken.
The SWMS must describe:
- the hazards and risks, including risk of electric shock
- what measures will be implemented to control the various risks
- how the controls will be implemented
The SWMS should include the process that will be used to verify de-energisation prior to working on the electrical installation.
Working in a ceiling space may also include other HRCW that must also be addressed in the SWMS. For more information on HRCW see SWMS in Related information.
Electrical work may involve other risks which must also be controlled, so far as is reasonably practical, such as:
- falls from height
- excessive heat
- biological hazards (vermin, insects, moulds)