Is My Old Fuse Box Dangerous? Ceramic Fuses, Rewirable Fuses and What NZ Rules Actually Require (2026)
An old ceramic or rewirable fuse box is not automatically dangerous — WorkSafe New Zealand's own position is that existing electrical installations can continue to exist and be repaired for as long as they remain safe. What actually matters is what a fuse board usually means in practice: no RCD safety switches, no spare capacity, and wiring old enough that nobody has tested it in years. That combination is what turns an old board from a curiosity into a real risk.
Not sure what's behind your fuse box door? Text a photo to 021 889 770 and we'll tell you straight whether it's fine, borderline, or overdue.
What's actually in an old fuse box
Ceramic rewirable fuses — fuse wire threaded through a porcelain holder, replaced by hand when it blows. Common in NZ homes built before the 1980s.
No RCD (residual current device) protection — the safety switch that cuts power in a fraction of a second if current leaks to earth. This is the single biggest gap, and it's the one that actually protects people, not just wiring.
A handful of circuits total — often four to six for the whole house, wired for an era with one heater and no dishwasher, heat pump or EV charger.
When it becomes a genuine problem
Burn marks, discolouration, a warm cover or a burning smell at the board — stop using it and call today, this is not a wait-and-see item
Fuse wire that's been replaced with the wrong gauge, or anything other than proper fuse wire — a genuinely common and genuinely dangerous DIY shortcut
No RCD anywhere on the board — not an emergency by itself, but the highest-value safety upgrade available in an older home
Fuses that blow repeatedly, or breakers mixed in beside old fuses in a way that looks improvised
No spare capacity for a heat pump, EV charger or kitchen upgrade you're already planning
What an upgrade involves and costs
A straight swap to a modern board with RCD protection typically costs $1,725–$4,600 including GST ($1,500–$4,000 + GST) in 2026, depending on circuit count and access, and usually takes half a day to a full day with the power off. Old fuses come out, modern breakers and RCDs go in, every circuit gets tested and labelled, and a Certificate of Compliance is issued on completion. Full detail in our switchboard upgrade guide.
Frequently asked questions
Are ceramic fuses illegal in NZ?
No. An existing installation with ceramic fuses can legally remain in use and be repaired, provided it's safe. There's no rule forcing every old fuse box in Auckland to be replaced — the case for upgrading is safety and capacity, not legality.
Will my insurer care that I have an old fuse box?
Increasingly, yes — some insurers now ask about board age and RCD protection at renewal or claim time. A documented upgrade removes the question entirely.
Can I just add RCDs to my existing fuse box instead of a full upgrade?
Sometimes, if the board itself is sound and has room — we'll test it and tell you honestly whether that's a real option or a patch that delays the inevitable.
Get a straight answer on your board
📞 Call 021 889 770 — book a switchboard assessment
📷 Text a photo of your fuse box to 021 889 770
Registered electricians on current EWRB practising licences · Certificate of Compliance and Electrical Safety Certificate issued within the statutory 20 days · Based in Remuera, working Auckland-wide