Replace Fuse in Fuse Box: Safe, Step by Step Guide for Homeowners

If you need to replace a fuse in a fuse box, this guide shows you exactly how to do it safely, which fuse to buy, and how to keep the same problem from happening again. This guide empowers homeowners to take control of basic electrical repairs safely.

You will learn how a fuse box works, how to spot a blown fuse, how to change a plug fuse or a cartridge fuse, and when it is smarter to call a licensed electrician. The guide is suitable for DIY enthusiasts, but also explains when to call a professional.

Having the right knowledge is key to safely replacing fuses and maintaining your electrical system. We will also clear up a common point of confusion about “blown fuse in circuit breaker,” since breakers and fuses protect circuits in different ways.

How a fuse box works and why fuses blow

A fuse is a sacrificial link that opens when current rises above the rating the circuit can safely handle. This stops the flow of electricity before wires overheat. In a home with a fuse box, individual branch circuits are protected by screw in plug fuses, and some larger circuits or the main disconnect may be protected by cartridge fuses.

When a “blown fuse” cuts power to part of your home, the fuse has melted internally by design. When a fuse blows, it interrupts the circuit to prevent damage, often indicating an issue with high-power appliances or a fault in the electrical system. A circuit breaker does the same job with a resettable switch, which is why searching for a “blown fuse in circuit breaker” often points to a tripped breaker, not a blown fuse.

Common reasons a fuse opens include an overloaded circuit, a short circuit, or a faulty appliance. If the same fuse opens repeatedly, there is likely a deeper problem that needs diagnosis, and fixing electrical issues should always be done safely, ideally by a professional.

Safety first before you touch the panel

Turn off the main power before replacing any fuse. This reduces the risk of shock when you remove a fuse or pull a cartridge block. Keep in mind that the service lines feeding the panel remain energized even when the main is off. Those lines and their lugs can carry lethal current. Do not touch them.

If anything looks damaged or scorched, stop and contact a licensed electrician to schedule a professional inspection to ensure safety.

Your basic safety checklist

• Wear dry shoes and keep your hands dry.
• Use a bright flashlight so you can see what you are doing.
• Do not work in standing water.
• If the panel is warm to the touch or there is a burnt smell, call a pro immediately.

Identify your fuse type and match the rating

Plug fuses look like small round devices with a glass window that screws into a socket, similar to a light bulb. Cartridge fuses are cylindrical and sit in clips inside a removable block or holder. Most branch circuits that serve lights and receptacles use 15 or 20 amp plug fuses, while larger appliances or the main disconnect may use higher rated cartridge fuses.

Always replace like with like. Match both the type and the amp rating that is printed on the fuse. Never install a fuse with a higher amperage than the original, or a higher rated fuse, in an attempt to prevent nuisance openings.

Using a fuse with higher amperage can allow wiring to overheat, which raises the risk of fire and serious safety hazards. For added safety, older panels with Edison style sockets should use Type S rejection adapters that accept only the correct fuse rating for each circuit. These adapters are designed to prevent overfusing.

If your home still has the older Edison base plug holders without adapters, ask about installing Type S adapters. They thread into the existing socket and then accept only the correct matching Type S fuse. Once installed, the adapter is not intended to be removed. This simple upgrade can prevent mistakes, especially in homes that share maintenance duties among several residents.

Tools and materials you will need

• Correct replacement fuse for your circuit, same type and same amperage
• Flashlight
• Insulated gloves
• Noncontact voltage tester or a multimeter
• Fuse puller for cartridge fuses, sized for your fuse holder

Tips for planning ahead: Here are some practical tips for homeowners to prevent power outages and stay safe. Keep a small kit with spare 15 amp and 20 amp plug fuses, plus the correct cartridge fuses for your main block if your panel uses them. Label the kit and store it next to the panel so you can act quickly during an outage.

Step by step: Changing a plug type fuse

1. Switch off the main power. Confirm that lights have gone out.
2. Find the affected circuit. Many panels are labeled. If not, look for a plug fuse with a darkened or broken element in the glass window. A continuity test can confirm it.
3. Unscrew the blown fuse and set it aside.
4. Insert the new fuse with the same amp rating and the same type, making sure it is carefully and securely placed in the holder. Hand tight is usually enough.
5. Flip the main power switch back on and test the circuit.

If the circuit works as expected, everything should be fine.

6. Watch for repeat problems. If the new fuse opens right away, stop and call a licensed electrician. There may be a short or a failing device on that circuit.

Step by step: Changing a cartridge fuse

Some homes use cartridge fuses for large appliances or as the main disconnect. These sit in a removable block. Proceed carefully and never force anything.

1. Switch off the main power.
2. Pull the cartridge block straight out using the handle. Do not touch any metal contacts.
3. Use a fuse puller to remove the cartridge from its clips.
4. Install the new cartridge with the same voltage and amp rating, fully seated in the clips.
5. Reinsert the block, ensuring it is in the correct position, and press it firmly into place.
6. Restore power and test the affected circuits. If the replacement blows again, the fuse or component may need to be replaced by a professional. Stop and call a pro.

A note on safety: a dedicated fuse puller improves grip and helps you maintain clear distance from energized parts. Choose one that fits the size of your cartridge fuses.

Electrical panel maintenance: Keeping your system safe and reliable

Keeping your electrical system in top shape starts with regular maintenance of your electrical panel, whether you have a traditional fuse box or a modern breaker panel. Routine checks help you spot early warning signs, like rust, corrosion, or water damage, that could lead to a blown fuse, short circuit, or even a fire. A well-maintained panel is your first line of defense against circuit overload, lost power, and other electrical hazards.

One of the simplest ways to protect your home is to keep the area around your electrical panel clear. Avoid stacking too many devices or storage items nearby, as clutter can make it harder to access the panel quickly in an emergency and may contribute to overloading circuits. Always switch off the main power switch before performing any electrical work, even for basic inspections, to reduce the risk of shock.

Regularly inspecting your fuse box or breaker panel can help you identify issues before they become serious. Look for any signs of damage, excessive wear, or outdated components. If you notice anything unusual, such as scorch marks, a burnt smell, or evidence of moisture, replace the affected parts promptly or contact a qualified electrician for a professional assessment.

Older homes, in particular, may benefit from upgrading to a modern breaker panel. Upgrading can provide better protection against overloading, short circuits, and repeated blown fuses, ensuring your electrical system can safely handle today’s power demands.

Why did the fuse blow and how to prevent a repeat

Overload – Too many devices running on the same circuit can push current beyond the fuse rating. Plugging several devices into one outlet can easily overload the circuit and cause a fuse to blow or a breaker to trip. Move high draw appliances to different circuits or run them at different times.

Short circuit – A damaged cord or a fault in a device can create a path with very low resistance. The fuse opens instantly. Inspect cords and devices for damage before you try again.

Ground fault – Water and electricity do not mix. If a circuit near a sink, laundry room, or laundry area is involved, ask about GFCI protection.

Good habits reduce nuisance outages – Spread kitchen countertop loads across multiple circuits when possible. Avoid multi plug adapters on a single receptacle. If lights dim or flicker when appliances start, have the circuit evaluated.

Fuse boxes versus breaker panels and when to consider an upgrade

Fuse boxes still provide overcurrent protection, yet they were designed for smaller household loads. Modern homes run more devices at once and benefit from the convenience and protection that contemporary breaker panels provide. Breaker panels support advanced safety devices like AFCI and GFCI that can reduce the risks of fire and shock.

Properly labeling each circuit and locating which fuse or breaker controls each area of your home is essential for efficient troubleshooting and safety. If your home still relies on a 60 amp fuse box or you have recurring outages across multiple circuits, it may be time to consider an upgrade.

AFCI protection detects arc faults that can start hidden fires. National safety organizations encourage AFCI protection across many living areas. GFCI protection helps protect people from electrical shock in areas with water or damp conditions. It has saved thousands of lives since the first requirements in the nineteen seventies.

Electrical fires and injuries are a real concern. Safety groups estimate that tens of thousands of home electrical fires occur in the United States each year, which is why safe fuse replacement and timely upgrades matter.

When to call a Professional

Call a licensed electrician if you notice burned insulation, melted parts, buzzing from the panel, repeated fuse openings, or any sign of heat or moisture. In an emergency, it is crucial to be able to quickly locate your electrical panel to shut off power safely. Panels are often located in garages, basements, or utility rooms, so knowing the exact location of your panel helps with faster troubleshooting and safer repairs.

If you have the older Edison sockets and no Type S adapters, it is smart to ask about adding them. If your home challenges a family’s routine with frequent outages, we can evaluate whether a modern breaker panel with AFCI and GFCI protection is a better long term answer.

A quick local note. Many homes near Cal Poly were built during earlier growth waves and still run on legacy electrical layouts. Our team understands those vintage fuse boxes, how to locate them if their location is unclear, and how to bring service up to the demands of today while preserving the character of the house.

Where we work

Service in San Luis Obispo with rapid response for no power calls and emergency diagnostics. Electrical panels in San Luis Obispo homes are often located in the basement, garage, or utility room, depending on the home’s layout.

Serving Los Osos and nearby areas with troubleshooting for repeated blown fuses and partial outages. In Los Osos, electrical panels are commonly found in the garage, basement, or utility room for easy access during maintenance or emergencies.

Service in Morro Bay and Avila Beach for panel evaluations and planned panel upgrades. Many homes in Morro Bay and Avila Beach have their electrical panels situated in the utility room, basement, or garage, especially in larger or older properties.

We schedule clean, on time visits and we protect floors and finishes while we work.

Frequently asked questions

How to change a fuse in a fuse box if I cannot tell which one is blown?
Turn off the main. Remove and test suspect fuses with a continuity tester or multimeter and replace only the one that is open. If labels are missing, take time to relabel as you go for easier service later.

How to replace fuse in fuse box without a fuse puller?
Plug fuses do not require a puller. Cartridge fuses are easier and safer with a proper puller sized for the fuse. If you do not have one, do not pry with tools that can slip. Get a puller or call a pro.

How to fix a fuse in a fuse box that keeps blowing?
Fuses open for a reason. Stop replacing and start diagnosing. Unplug high draw appliances, examine cords, and call an electrician if the circuit still fails. Persistent problems can signal wiring issues that need professional attention.

Is there such a thing as a blown fuse in circuit breaker panels?
Circuit breakers do not contain fuses for ordinary branch circuits. A tripped breaker can be reset after the cause is corrected. Some older homes use a combination of breakers and cartridge fuses for large appliances or for the main disconnect.

Can I use a higher amp fuse so it stops blowing?
No. Never install a fuse with a higher rating than the circuit is designed for. Doing so can allow dangerous overheating of wires. Use the exact same type and amp rating as the fuse you removed.

Final checklist before you close the panel

• Main off, correct fuse matched, and installed firmly
• Circuit tested under a normal load
• Labels updated so the next replacement takes less time
• Spare fuses stored next to the panel for future use

Replace Your Fuse with SLO Modern Electric

We help homeowners and property managers handle everything from a single blown fuse to full panel upgrades. Our electricians explain options in clear language and leave your space tidy. If you have questions about fuse boxes, breakers, or how to plan a smooth upgrade, we are ready to help. Contact us today!