Sub-Board Installation in Perth: When and Why You Need One
Sub-board installation is the smart solution when a shed, granny flat, pool or extension needs its own reliable power supply. Rather than overloading your main switchboard, a sub-board installation gives the new area its own protected distribution point. Here is when you need one, what is involved, and what it costs.
What is a sub-board?
A sub-board, or sub-distribution board, is a smaller switchboard fed from your main switchboard, with its own circuit breakers and RCDs for a specific area. A sub-board installation lets you safely power a separate building or zone, like a shed or granny flat, without running every circuit back to the main board.
6 reasons to consider a sub-board installation
- Powering a shed, workshop or garage
- Adding a granny flat or studio
- Running pool, spa or outdoor equipment
- Supplying a home extension
- Freeing up space on a full main switchboard
- Keeping a separate area’s circuits organised and protected
Why not just add to the main board?
Sometimes you can, but a sub-board installation is better when the main board is full, the new area is some distance away, or the load is significant. Running one larger cable to a sub-board and distributing locally is tidier, safer and often cheaper than running many long circuits back to the main switchboard.
What a sub-board installation involves
A sub-board installation means running a suitably sized supply cable from the main switchboard to the new location, mounting and wiring the sub-board with its own breakers and RCDs, then connecting the local circuits. For a detached building, this may involve underground cabling and careful load calculation.
Sub-board installation cost in Perth
Cost depends on the distance from the main board, whether cabling is run overhead or underground, the size of the supply needed, and how many circuits the sub-board feeds. A simple sub-board installation is moderate, while a distant building with trenching costs more. Every job is quoted after an assessment.
Sheds, granny flats and pools
These are the most common reasons for a sub-board installation. A shed or workshop with power tools, a granny flat with its own kitchen and aircon, or a pool with pumps and lighting all benefit from a dedicated sub-board that keeps their circuits protected and separate from the main house.
Why use a licensed electrician
A sub-board installation involves your main supply, load calculations and proper protection, so it is licensed work. A licensed electrician sizes the supply, installs the board to standard, and certifies it. The state’s Building and Energy sets the standards the work must meet.
Sub-board vs a main board upgrade
A sub-board is not the same as upgrading your main switchboard. An upgrade modernises the main board, while a sub-board extends protected power to a new area. Sometimes you need both, and an electrician will advise which suits your situation and budget.
Detached buildings and trenching
When the new building is detached, the supply cable usually runs underground in conduit, which means a trench across the yard. It is worth planning this alongside any other groundwork, like a new driveway or landscaping, to save digging twice.
Getting the size right
The most important part of the job is sizing the supply correctly for the loads the area will run, now and in future. An undersized supply trips and struggles, while a well-sized board handles tools, appliances or pumps comfortably. This is exactly why a professional assessment matters.
Adding a shed, granny flat or pool in Perth?
ACS Electrical handles sub-board installation across the metro, sized and protected for the job. Explore our switchboard upgrades service, three phase upgrade guide or switchboard relocation guide. Call 0419 967 838.
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