Australia's housing stock contains a significant number of switchboards that were installed in the 1960s, 1970s, and early 1980s and have never been upgraded. Many of these boards use rewireable ceramic fuses as the only form of overload protection — a technology that relies on the owner replacing blown fuse wire with the correct ampere rating, which rarely happens in practice. Some boards have had safety switches bolted on as an afterthought, covering only one or two circuits and leaving the rest of the installation without residual current protection. If you own or manage one of these properties, you are carrying risk that a modern switchboard eliminates at a cost that is, in most cases, less than a single insurance excess.
What is wrong with an old fuseboard?
Rewireable fuses have three fundamental problems. First, they do not provide residual current protection — they only respond to a sustained overcurrent, not the small fault currents that cause electrocution and many electrical fires. Second, they are routinely 'repaired' with incorrect fuse wire or, in the worst cases, with nails and wire, which removes any overload protection entirely. Third, they rely on the fuse carrier and holder to be in good mechanical condition after forty or fifty years of service — and old bakelite and ceramic fuse holders crack, corrode, and develop high-resistance connections that generate heat in a board that nobody is watching. A modern residual current circuit-breaker (RCCB) or residual current circuit-breaker with overload protection (RCBO) combines overload, short-circuit, and earth-fault protection in a single device that operates automatically and resets cleanly.
RCBOs versus RCDs and circuit breakers — what is the difference?
An RCD (Residual Current Device, sometimes called a safety switch) monitors the current flowing out of a circuit against the current returning and trips in approximately 30 milliseconds if the imbalance exceeds 30 milliamperes — a level that can cause cardiac fibrillation. An RCBO combines that RCD function with a conventional circuit breaker, providing overload and short-circuit protection as well. The advantage of individual RCBOs per circuit is selectivity: if a fault occurs on one circuit, only that circuit trips. An arrangement with a shared RCD protecting a group of circuits trips the entire group when one circuit faults, which in a commercial kitchen or a home with medical equipment is the difference between an inconvenience and an emergency. SynthWire configures switchboards with individual RCBOs on all final sub-circuits as the default standard, with grouped RCDs used only where the load profile makes them appropriate and the client understands the trade-off.
Surge protection devices (SPDs)
The 2018 edition of AS/NZS 3000 introduced provisions for surge protective devices in residential and commercial switchboards. A Type 2 SPD installed at the main switchboard clamps voltage transients from nearby lightning strikes and DNSP network switching events that would otherwise travel through your wiring and damage connected equipment. With the proliferation of sensitive electronics — smart inverters, EV chargers, home automation systems, and commercial POS terminals — the cost of an SPD installation is easily justified against the replacement cost of the equipment it protects. SynthWire installs SPDs as part of all new switchboard builds and as a retrofit to existing compliant boards.
Metering, labelling, and load balancing
A switchboard that has grown organically over decades is often a labelling disaster: circuits marked 'kitchen' covering three different areas, unlabelled breakers of unknown function, and load distribution across phases (in three-phase installations) that has never been reviewed. When we install a new board, we carry out a load audit — we measure the actual current draw on each circuit under normal operating conditions and balance the phase loads where three-phase supply is available. Every circuit breaker is labelled clearly and permanently with the room and function it controls. The directory inside the board door is typed, printed, and laminated. This is not a cosmetic nicety; it is the difference between a fault being isolated in thirty seconds and someone standing in front of an unfamiliar board in the dark during an emergency.
What the upgrade process looks like
Most residential switchboard upgrades complete in a single day. We arrive, de-energise the existing board (coordinating with your DNSP for any metering point work), install the new enclosure and equipment, reconnect and test every circuit individually, confirm RCD trip times within the 300 milliseconds maximum permitted by AS/NZS 3000, label the directory, and restore supply. You receive a Certificate of Compliance before we leave. We also carry out a visual inspection of the cabling connected to the new board during the reconnection process — if we find deteriorated insulation or undersized cable during this work, we will flag it and give you options before reconnecting that circuit. No surprises on the invoice; any additional work is quoted and approved before it proceeds.
- Full switchboard replacement — ceramic fuse to modern RCBO panel
- Individual RCBO installation on all final sub-circuits
- Grouped RCD upgrade for shared-protection arrangements
- Surge Protective Device (SPD) installation — new boards and retrofits
- Three-phase load balancing and phase metering
- Sub-metering for solar, EV charger, and cost-recovery applications
- Full circuit labelling with permanent, typed directory
- Certificate of Compliance and DNSP notification as standard
Frequently asked
Most homes and small commercial premises lose supply for three to five hours during the main switchboard work, with full restoration before we leave the site. We co-ordinate the supply outage to suit your schedule and, where you have time-critical loads such as refrigeration or medical equipment, we discuss alternatives — including temporary generator supply — during the planning stage.
Insurers typically want confirmation that the switchboard has been inspected by a licensed electrician, that it contains current residual current protection on all circuits, and that the installation is compliant with AS/NZS 3000. After an upgrade or inspection, SynthWire provides a Certificate of Compliance that documents the installed protection and the date of the compliant installation. If a written condition report is needed for an insurer before an upgrade is required, we can provide that as a separate inspection service.
It depends on the type and condition of the existing board, how many spare ways it has, and what the existing protection arrangement is. If your board is a modern, compliant unit with spare circuit positions, adding circuits is straightforward. If the board is full, uses rewireable fuses, or has insufficient RCD coverage, a replacement is almost always the better long-term option economically. We will assess your board and recommend the most cost-effective approach during the inspection.