Montreal – Laval – Laurentides – Lanaudiere

Is a fuse sign safe?

panneau à fusible

So we need to clarify this subject. Compare the fuse panel to the circuit breaker panel. Many people mistakenly think that fuse panels are outdated and dangerous. When properly installed, the fuse panel is very safe. The operation of a fuse is very different from that of a circuit breaker. A master electrician can guide you on replacing your electric panel, if necessary.

How a fuse works

There are many different types of fuses but these have mainly the same function. What will vary is the time with which the fuse will cut the circuit. The electric current passes through the fuse and crosses it entirely. When this current exceeds the maximum allowable amperage for this fuse, the conductive part melts and opens (opening a circuit means closing the current) as well as the electrical circuit.

Fuse disadvantages

The main disadvantage of the fuse is that it cannot rearm like a circuit breaker. It is therefore inconvenient when a fuse burns! If we don’t have one at home, you have to go to hardware stores to buy them. The second biggest disadvantage is in the capacity of the fuses. It is this point that drives insurance companies to ban the use of fuse panels and makes these signs dangerous…

Where it’s dangerous…

People don’t know it, but the fuse or circuit breaker is there to protect wiring, equipment and humans. The problem with fuse caps is that they are all the same size and are easy to replace. The natural reflex of people when a fuse continuously jumps is to install one with greater capacity. The fuse of 15 amps does not stop jumping and it is not convenient! We’re going to put a 20 amps. Oh, shit! It’s still jumping, we’re going to install a 30 amps! Indeed, the fuse no longer burns. However, the entire electrical system is overheating: the wiring, the sockets and all the components. That’s where the worst can happen.

How a circuit breaker works

The most used circuit breaker is the magneto-thermal. The circuit breaker has mainly 2 functions:

  1. Protect an overload (too high an amperage in the circuit)
  2. Protect a short circuit (contact between lines and neutrals and/or groundings)

The operation of the fuse is relatively complex to explain and I will not get into the heart of the matter. It should also be noted that some circuit breakers are NOT safe because of their manufacturing defects. A master electrician will be able to guide you on circuit breakers that are to be avoided/replaced and those that are reliable.

disjoncteur magneto thermique
Exploded view of a magneto-thermal circuit breaker

We talked about the two main functions of the circuit breaker. The first function is to protect the overload, excessive use and above the amperage available on an electrical circuit. It’s the heat protection of the circuit breaker. It is the continuous heat that triggers this system. This is why it may take several seconds for the circuit breaker to go off. When the excessive current passes through the bilame (#5 in the photo),it gradually deforms until it mechanically triggers the contact (#3 in the photo). This is why sometimes some circuit breakers cannot rearm immediately after overloading. We have to wait for the bilame to cool down.

The second function is to protect the short circuit. The short circuit causes an incredibly high increase in amperage in the circuit (several thousand ampers). The thermal protection explained above would be too slow to react and electrical installations could be damaged with this technique. It is the magnetic protection of the circuit breaker that limits the short circuits. The very high-intensity current passes through a coil (#7 in the photo). This coil creates a magnetic field that moves a rod that causes the circuit breaker to trigger. It is much the same function as a house chime.


Most of the time, replacing a fuse panel for circuit breakers will save you money on your insurance bill. The circuit breaker panel is easy to re-arm if something goes wrong. The new electricity needs will be easier to meet if you have a circuit breaker panel. Breakers are found all over the market while fuses are harder to find. The circuit breaker panel gives you more flexibility in the number of circuits.

The benefits of the circuit breaker panel

  1. Savings on insurance bill
  2. Ease of rearming circuits
  3. Easier to add new circuits or electrical modifications
  4. Low prices
  5. High availability on the market
  6. Flexibility in the number of circuits
  7. No risk of error on fuse capacity

So to conclude, fuses are safe. However, in a residence, the circuit breaker panel is highly recommended due to its many advantages.