Hidden Dangers in Older Consumer Units (Fusebox)
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- 15 hours ago
- 3 min read
When I go into older homes in our area (Chilcompton, Midsomer Norton or Wells and Frome), one of the most common things I see is an old-style consumer unit quietly doing its job… or at least it’s trying to - you have to feel for it… because it’s just not as efficient and safe as it’s newer counterparts and there are hidden dangers in older consumer units!
From the outside it might look fine, albeit very old fashioned.
But inside, there can be some very real hidden risks.
Here’s what homeowners need to know.
ASBESTOS
They often have asbestos hidden within them… not just around the circuit breaker but in some cases you will find that a common thing to do was to wrap the cables within the consumer unit in asbestos wool…
No RCD Protection (The Big One)
Many older fuse boards (especially ones with rewireable fuses or early MCBs) don’t have RCD protection. An RCD (Residual Current Device) is what trips the power in milliseconds if there’s an earth fault — for example:
Cutting through a cable
A faulty appliance
Water getting into electrics
A child touching something they shouldn’t
Without RCD protection, electricity can continue flowing long enough to cause:
Serious electric shock
Fire
Damage to wiring hidden in walls
Modern regulations require RCD protection on most circuits for a reason. It genuinely saves lives.
Old Rewireable Fuses
Those old fuse wires might seem simple and reliable — and they were in their day.
The issue is:
They’re easy to “overfuse” (people put thicker wire in)
They don’t trip as quickly or as accurately as modern breakers
They’re not sensitive to earth leakage faults
I’ve seen plenty where the fuse wire is the wrong rating, meaning the cable behind the wall could overheat before the fuse blows.
That’s where hidden fire risk creeps in.
No Surge Protection
Older boards don’t include surge protection devices (SPDs).
With today’s homes full of:
Smart TVs
Laptops
Boilers with circuit boards
EV chargers
Smart heating systems
A voltage spike can cause serious damage.
Power surges aren’t just from lightning — they can happen from network switching events too.
Modern consumer units can include SPD protection to help protect thousands of pounds’ worth of electronics.
Loose Connections & Heat Damage
Consumer units from the 60s–90s weren’t designed for the electrical load we use today.
Add in:
Electric showers
Induction hobs
EV chargers (the regulations wouldn’t allow you to anyway!)
Tumble dryers
And you’ve got a system that may be running close to its limits.
Over time, connections can loosen, especially on older boards. Loose connections = heat.
Heat inside a consumer unit is never something you want.
I’ve opened boards before and found:
Scorch marks
Melted insulation
Signs of arcing
Often the homeowner had no idea.
No Fire-Rated Enclosure
Modern consumer units are metal-clad and designed to contain a fire if something goes wrong internally.
Older plastic units?
Not so much.
In the unlikely event of a fault causing ignition, plastic enclosures can contribute to fire spread rather than contain it.
It’s one of those quiet regulation changes that came in after real incidents.
Lack of Circuit Separation
Older boards often have fewer circuits.
That means:
Lights and sockets sharing circuits
Entire upstairs or downstairs on one breaker
Kitchen on a single circuit
The risk?
Faults take out big parts of the house — and more importantly, fault discrimination (how quickly and selectively something trips) just isn’t as effective.
Modern boards split circuits properly and offer RCBO protection per circuit, which is far safer and far less disruptive.
The Real Danger: False Sense of Security
This is the bit homeowners don’t see.
If the lights work and nothing trips, people assume everything’s fine.
But electrics age quietly.
Cables degrade. Connections loosen. Standards improve.
An old consumer unit doesn’t automatically mean “danger”, but it does mean:
Reduced protection
Higher fire risk
No compliance with current safety standards
Possible insurance implications
When Should You Be Concerned?
You should seriously consider an inspection if:
Your fuse board has rewireable fuses
It’s plastic and 20+ years old
There’s no RCD test button
You’ve added big electrical loads over the years
You’re planning renovations or an EV charger
An EICR (Electrical Installation Condition Report) will tell you exactly where you stand.
If you need any electrical work you can call Rich now on 01761 325 007 or visit my website to find out more https://www.spellerssparks.co.uk
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