Written By: Andrew Smith
When I started my career as an electrician, one of the most common calls I got was from people whose fuse had blown. Often, they were scared to touch anything, worried about electric shocks, or simply didn’t know how to replace a fuse safely. Over the years, I’ve learned that with a little knowledge and the right precautions, changing a fuse is straightforward—but it must always be done carefully.
Here’s my step-by-step guide from real experience, including safety tips, common mistakes, and advice I give all my clients.
What is a Fuse and Why It Blows
Before we start, let’s understand what a fuse does. A fuse is a safety device inside your fuse box (or consumer unit). Its job is simple: it stops electricity from flowing if there’s too much current. Without a fuse, electrical faults could cause overheating or even fires.
In older homes, you’ll often find screw-in fuses, while modern homes mostly use circuit breakers. I always tell clients: “If your home has an old-style fuse box, consider upgrading—it’s safer and easier to maintain.”
Fuses usually blow because:
- Overloading a circuit (too many appliances on one socket)
- Faulty appliances
- Wiring issues
Safety First: What You Need to Know
From years on the job, I can’t stress safety enough. Never rush this process. Here’s what I always do before touching a fuse:
- Turn off the main switch – This ensures there’s no electricity running to the fuse box.
- Wear insulated gloves – Even small shocks can be painful.
- Use the right fuse – Match the amperage exactly. Using a higher-rated fuse can cause fire risks.
- Check appliances – Sometimes the fuse keeps blowing because an appliance is faulty.
Step-by-Step: How to Change a Fuse
Here’s the process I follow on every job:
Step 1: Identify the Blown Fuse
Look at your fuse box. A blown fuse often has a melted wire or blackened tip. In older screw-in fuses, the filament inside is broken. In modern cartridges, the plastic may be discoloured.
Step 2: Turn Off the Main Power
Even if the fuse is blown, always switch off the main power. This protects you from accidental shocks.
Step 3: Remove the Blown Fuse
For screw-in fuses:
- Use a fuse puller or insulated gloves.
- Twist and pull gently.
For cartridge fuses:
- Unscrew or unclip according to the unit’s design.
- Handle carefully.
Step 4: Check the Fuse Rating
Look at the numbers on the old fuse—usually 3A, 5A, 13A, etc. Never replace with a higher rating; it can be extremely dangerous.
Step 5: Insert the New Fuse
- Screw in or clip in the new fuse.
- Ensure it’s seated properly—loose fuses can cause arcing and fire.
Step 6: Turn On the Power
Switch the main power back on.
- If the new fuse blows immediately, there’s an underlying problem. Call a qualified electrician.
Common Mistakes I See
Over my years in the field, these are the most frequent errors:
- Using a fuse with the wrong rating
- Not turning off the main switch
- Touching the metal part of the fuse directly
- Replacing a blown fuse without checking for faulty appliances
- Ignoring recurring fuse blows
I always tell clients: “A blown fuse is not just a nuisance—it’s a warning. Don’t ignore it.”
When to Call an Electrician
Sometimes, a blown fuse is just a one-time event. But if it keeps happening, it could mean:
- Faulty wiring
- Overloaded circuits
- Faulty appliances
- Outdated fuse box
In these cases, never keep replacing the fuse repeatedly. Call a certified electrician—safety comes first.
Quick Tips from Experience
- Keep spare fuses at home, but only the correct type.
- Label your fuse box so you know which fuse controls which area.
- Consider upgrading to a modern consumer unit with RCD protection if you have an old-style box.
Changing a fuse may seem simple, but doing it safely is crucial. From my experience, respecting the process and knowing when to call a professional is what prevents accidents and keeps your home safe.
Final Words
Always switch off the main power, use the correct fuse, and never ignore recurring issues. A little care goes a long way in protecting your home and family.
