回路ブレーカーの交換方法

A circuit breaker is an electrical protection device that safely interrupts the flow of electricity in the event of an abnormal current, protecting your circuits and equipment from damage and preventing the risk of fire. When a circuit breaker is not functioning properly, you need to replace it promptly to ensure safety. This article will give you detailed instructions on how to replace a circuit breaker.

Step 1: Selecting the Right Circuit Breaker

First, you should carefully check the markings or instructions on the old circuit breaker for the model number and capacity of the breaker. And make sure that the new サーキットブレーカー has the same current rating, number of poles, and installation as the old one. You also need to confirm the specification, type and model of the circuit breaker panels. Mixing different models can lead to poor links and even safety accidents. So you’d better work with a safe and reliable manufacturer of circuit breakers and circuit breaker panels.

Step 2: Preparation Tools

• Screwdrivers: Have the right size Phillips and 1-head screwdriver and make sure it is insulated. This is used to remove and install panels and wires.
• Multimeter: Have a reliable multimeter or voltage test pen on hand to verify power loss.
• Headlamp or torch: When the power is off, it’s dark when you’re operating. Have a torch or headlamp to ensure that the inside of the switchboard is well-lit.
• Insulated Gloves and Goggles: It is a good idea to wear insulated gloves and goggles that meet the standards of an electrician to ensure your safety.
• Other tools you may need: Electrical tape for temporary fixing, insulated sharp-nosed pliers, wire stripper.

Note that it will be more convenient for you to clear the debris around the distribution box before the operation. During the replacement process. You must stand on a wooden board or dry, insulated floor mat and never wear metal jewellery. It is also advisable to have another person present to assist you in the operation and to know how to cut off the power and call for help in case of an emergency.

Step 3: Cutting off the Main Power Supply

Switch on the headlamp and locate the main power switch in the distribution box and turn it to the OFF position. If your distribution box is multi-story, disconnect the floor main switch first, then the main power distribution switch. Start by testing a powered circuit breaker with a multimeter or circuit pen to make sure it works. Then use it to test the incoming terminals of the old and new circuit breaker to make sure there is no voltage.

Step 4: Open the Circuit Breaker Panel

Use a suitable screwdriver to remove the screws and carefully open the circuit breaker panel. Place the cover plate and screws where they will not get in your way. Do not lose the screws, they will be needed for subsequent installation of the cover plate. Note that the mains incoming cable inside the panel remains energised after the mains switch has been turned off, so do not touch it.

Step 5: Disconnect the Load Line

There are usually two wires connected to the circuit breaker. One is the fire wire from the power source, and the other is the load wire that goes to the device. You need to locate the load wire of the old circuit breaker. It is usually black or red and is screwed into the terminal hole. Remove it carefully using a screwdriver. You can use sharp-nosed pliers to assist in pulling it out, it is best not to bend the wire. Then wrap the end of the exposed copper wire with insulating tape.

Step 6: Remove Old Circuit Breakers

General Circuit Breaker

Circuit breakers are usually secured to the mounting rails on the inside of the panel using snap hooks, and the other end snaps into the busbar. Use a screwdriver to pull the end of the breaker outward to disengage it from the busbar. Then remove it from the mounting rail.

Special Circuit Breakers

If you have a double-pole or multi-stage breaker, you will need to operate both ends at the same time to disengage the connections from the busbar and then remove it from the rail. Additionally, for GFCI/AFCI breakers, the neutral lead connected to the bus bar must be removed. It is usually a white flexible wire.

Step 7: Install New Circuit Breakers

Check the new circuit breaker for cosmetic damage. You should keep the wire ends of the new breaker clean and tight. If the wire ends are damaged and oxidised, use wire strippers to strip out 0.5 inches of clean copper wire. Then you should add the circuit breaker to the Electrical Panel. To install the breaker, hang the section with the snap hooks on the mounting rails on the inside of the panel, then push the other end of the breaker into the slot against the bus bar. Slightly wiggle to make sure there is no looseness in the installation.

Step 8: Connecting the Load Line

Locate the junction hole marked “LOAD”. Remove the insulation tape from the end of the copper wire and insert it straight into the load terminal hole of the new circuit breaker. Make sure there are no loose copper wires, then use an insulated screwdriver to tighten the wiring screws. You have to stabilise the load line and not touch any other metal parts. Failure to do so can lead to overheating or even cause a fire.

Step 9: Testing New Circuit Breakers

Power on Test

Check the inside of the panel for any other debris and clean it out, reconfirm the new breaker is well connected, and then put the panel cover back on. Restore mains power by firstly triggering the main circuit breaker handle to the ON position. Then move the new circuit breaker handle to the ON position and test the equipment on the line to see if it works properly.

Load Test

To verify that there is no error in long-term use, you can perform a load test. Connect a load close to the rated capacity to the line again and run it for a few minutes. Observe whether the new circuit breaker trips again, gets hot, or makes strange noises. If there is a problem, the power must be turned off immediately for servicing. If all is well, you’ve succeeded in replacing the breaker. If your circuit breaker is experiencing problems that are difficult to fix, it’s best to contact a professional to have it serviced.

結論

Following the steps in this post can help you replace your disconnect quickly. If you are looking for a suitable electrical panel for a magneto-thermal breaker or are in need of a custom panel, KDMスチール should be your first choice. If needed, please contact us immediately.

よくある質問

What to Do If It Still Doesn’t Work after Replacement?

Firstly, check that the mains power is restored properly and use a multimeter to measure whether there is power input at the circuit breaker wire end. Also check that the breaker wires are connected properly. You can try disconnecting the devices in the circuit to rule out whether it is overloaded. If all is well, it’s best to contact a professional to have it serviced.

Can I Use a Higher Current Breaker to Prevent Tripping?

Can’t. The trip is to protect the wiring. Switching to a higher current circuit breaker could cause the wires to overheat or even catch fire. You should choose a circuit breaker that matches the design of the circuit.

When Do I Need to Replace a Circuit Breaker?

• Frequent Tripping: The circuit breaker will trip when your power supply is overloaded. Occasional tripping due to improper use is normal. However, if your circuit breaker is tripping frequently, you need to check the condition of the breaker and replace it.
• Damage or odour: If you notice damage to the appearance of the circuit breaker, such as burnt, melted, cracked or corroded. Please replace it promptly. If there is no damage to the exterior, but there is an odour such as a burnt smell. You also need to replace it as soon as possible.
• Long use: Circuit breakers can last you 40 years though. But as you use it longer, its performance decreases. To better ensure your safety, it is best for you to replace your aging circuit breaker in a timely manner.

Can I Replace a Circuit Breaker If I’m Not a Professional?

Honestly, it is possible if you have a solid grasp of basic electrical principles, understand how circuits and breakers function, and, crucially, if you use the correct tools and follow strict safety procedures step-by-step. However, this is potentially dangerous electrical work. If you’re not completely confident in your knowledge or comfortable working inside your electrical panel, or if your home has a more complex electrical system, it’s strongly advised to hire a qualified professional electrician to handle the replacement safely.