One of the recurring patterns in our work across the Lower North Shore is that the switchboard story rarely matches the look of the house. A beautifully kept Lane Cove home from the early 1990s, fresh-painted and meticulously maintained on the outside, will routinely have a switchboard inside that is one renovation away from being a serious problem. We finished a job in Lane Cove a couple of weeks back that was a great example of this — and a great example of how a renovation forces the switchboard conversation that probably should have happened five years earlier. Here’s how it played out.
The Lane Cove brief
The clients were doing a major renovation: opening up the rear of the house into a new kitchen-living-dining zone, adding ducted air conditioning, and converting the existing detached garage into a self-contained granny flat for an elderly parent moving up from Wollongong. The builder had been on site for six weeks when the electrician they’d lined up took one look at the switchboard, said “you’ll need to talk to a switchboard specialist about this one,” and quietly stepped back from the job. We got the call that afternoon.
Why the existing board couldn’t handle the renovation
The original board was three-phase — Lane Cove and a lot of the inner-northern suburbs were wired three-phase as standard for larger homes — but it was a 1990s metal-fronted enclosure that had been gradually filled across three decades. Two sub-boards had been added, both lazily, on flying conductors that were never properly engineered. The main switch was rated for the original load, not the proposed renovation load (which was about to add ducted air-con, an induction cooktop, an electric vehicle charger, and the granny flat). And there were almost no RCDs anywhere — three of them across the entire house, none on the lighting circuits. None of this is unusual for a board of that vintage. But you can’t add a kitchen renovation, ducted air-con, an EV charger, and a self-contained dwelling on top of a board like that and expect anything good to happen.
Splitting the three-phase load properly
The first decision on a three-phase upgrade is always how you split the load across the three phases. Done badly, you end up with one phase carrying the kitchen, the laundry, the air-con and half the lights while the other two phases sit lightly loaded — and the network operator notices when one phase is tripping the main switch repeatedly. We mapped the existing circuits, then redesigned the new board so the load balanced across all three phases: kitchen and induction on phase one, ducted air-con and EV charger on phase two, lighting and general power on phase three, with the granny flat sub-board fed from a separate phase entirely. This is the kind of detail clients don’t think about — and shouldn’t have to — but it makes the difference between a board that runs cool and reliably and one that’s always one heatwave away from problems.
The granny flat sub-board
The detached garage conversion needed its own sub-board, properly fed and metered. We ran new sub-mains underground from the main switchboard to the granny flat, sized generously for future expansion, and installed a dedicated sub-board with full RCBO protection on every circuit. Critically, the granny flat is on its own meter so the parent’s energy use is tracked separately. The garage conversion specialists doing the actual building work appreciated being able to lock down the electrical scope early — for anyone planning a similar project, the conversation between the builder, the electrician and the granny-flat designer needs to happen before the switchboard is specified. For the broader Brisbane equivalent of this kind of project, our network has covered garage-to-granny-flat conversions in detail, and the electrical principles carry over.
What the renovation electrical actually involved
For the main house, we replaced the existing enclosure with a much larger flush-mount three-phase board sized for current load plus 30% future capacity. Every circuit got its own RCBO. We added isolators and labelling for the planned solar-and-battery install (now scheduled for next quarter), and a dedicated EV charger circuit with its own load management capability so the charger plays nicely with the rest of the home’s loads at peak times. For more on the EV charger considerations, see our piece on EV chargers and Sydney switchboard upgrades. Solar pre-wiring is covered in our piece on preparing your Sydney home’s switchboard for solar and battery storage.
The Ausgrid co-ordination
Three-phase work in Lane Cove involves a higher level of Ausgrid co-ordination than a single-phase job. We had to schedule the supply isolation through Ausgrid (not just throw the main switch ourselves), which meant the work needed to fit a one-day window booked weeks in advance. The clients had to plan around no power in the main house for about six hours, which we covered with a generator running the fridge, freezer and a few essential outlets. The granny flat side was wired up while the main house was de-energised, which let us do everything in a single day rather than splitting it across two visits.
What we found behind the original board
This is the part that always surprises clients. When we pulled the old enclosure off the wall, we found the sub-mains feeding it were undersized for the current load — they’d been adequate when the house was new but had been overloaded for at least a decade. They also weren’t secured properly inside the wall cavity. We replaced them as part of the upgrade, which wasn’t in the original quote — but it absolutely had to happen. Honest electricians flag these things mid-job rather than ignoring them, and most clients are glad we did when they understand why. For homeowners looking for the warning signs in their own boards before things get this bad, our piece on the signs your Sydney home needs a switchboard upgrade is a useful starting point.
The handover
Two days after the main install we were back to commission the granny flat, test every RCBO, run a full electrical safety report, and label every circuit on the face of the board so the homeowners can find the right switch in seconds. The board now has clear signage indicating three-phase supply, the future solar isolation, and the granny flat sub-board feed. The renovation builder picked up where he’d left off the next morning, and the kitchen and air-con tradies came in the following week with no further electrical surprises. For more on what these days actually look like from the homeowner’s side, see our piece on switchboard upgrade installation day.
What this means for other Lane Cove, Roseville and Chatswood homes
If you’re in Lane Cove, Roseville, Willoughby, Chatswood or Hornsby and your home was built or last rewired in the 1980s or 1990s, the chances are very high that the board hasn’t kept up with how the house has actually been used since. Renovations are the natural moment to fix that — but you don’t need to wait for a renovation if the warning signs are already there. Our pieces on safety switches vs circuit breakers and the broader signs of an ageing board are a good starting point. We’re always happy to do an honest on-site assessment before you commit to anything, especially if a renovation is on the horizon.