Many homes and rental properties have more than one electrical switchboard. While the main switchboard is usually located near the electricity meter, additional sub-boards are commonly installed in garages, workshops, sheds, extensions and detached buildings.
To help ensure these installations can be safely isolated, the Australian/New Zealand Wiring Rules (AS/NZS 3000) require sub-boards to have an appropriately identified Main Switch (Main Isolator) so the electrical supply can be safely disconnected when required.
What Is a Sub-Board? #
A sub-board is a secondary switchboard that receives power from the property’s main switchboard. It distributes electricity to a specific area or building and provides protection for the electrical circuits connected to that section of the installation.
Sub-boards are commonly found in:
- Detached garages
- Workshops
- Granny flats
- Home extensions
- Large residential properties
- Sheds and outbuildings
- Commercial premises
Why Is a Main Switch (Main Isolator) Important? #
A clearly identified Main Switch (Main Isolator) allows the electrical supply to that section of the property to be isolated without shutting down power to the entire premises.
This improves safety during:
- Electrical maintenance
- Repairs and upgrades
- Fault finding
- Emergency situations
- Testing and inspection work
Quickly identifying the correct isolating switch helps reduce the risk of working on live electrical equipment and assists electricians and emergency services when power needs to be disconnected.
Australian Wiring Rules Requirements #
Electrical installations in Australia must comply with AS/NZS 3000 (Australian/New Zealand Wiring Rules).
Where a sub-board supplies a separate electrical installation or outbuilding, the switchboard must have an appropriately identified Main Switch (Main Isolator) that allows the installation to be safely isolated for maintenance or emergency purposes.
Common Issues Found During Electrical Safety Inspections #
Our licensed electricians regularly identify issues such as:
- Missing Main Switch (Main Isolator) labels
- Switchboards with no obvious isolating switch
- Incorrect or faded identification labels
- Multiple switchboards with unclear identification
- Renovations where additional sub-boards have been installed without updating labels
Although these issues may seem minor, they can delay emergency isolation and make electrical work more difficult and potentially unsafe.
Why This Matters for Victorian Rental Properties #
Victorian rental properties are required to undergo prescribed electrical safety checks at the required intervals and electrical installations must be maintained in a safe condition.
A clearly identified switchboard assists licensed electricians when carrying out electrical safety inspections and helps ensure electrical systems can be safely isolated during maintenance or emergencies.
If switchboard labels are missing, damaged or no longer accurate, they should be assessed and updated by a licensed electrician.
Book an Electrical Safety Inspection #
Rental Safety Inspections provides professional electrical safety inspections for rental properties throughout Melbourne and surrounding areas.
Our licensed electricians inspect switchboards, Main Switches (Main Isolators), safety switches (RCDs), smoke alarm circuits, wiring and other electrical components as part of Victoria’s prescribed rental electrical safety inspections. We help identify defects that may require attention and support compliance with applicable electrical safety requirements.
Contact Rental Safety Inspections today to book your next electrical safety inspection.
