Is it the culprit of the power outage? Maintenance and electrical protection guide for frequent tripping of "leakage circuit breakers" in old apartments

In modern life where electrical appliances are frequently used, old apartments in the greater Taipei area often hear exclamations like: "The power has tripped again!" When you walk to the main electrical box at home, you find that a switch is hanging down. Many people's first reaction is to push it back immediately, but if the switch is an "earth leakage circuit breaker (ELCB)" with a "test button" and it pops open as soon as it is pushed up, please do not force it back or fix it with tape! Because this means that an electrical appliance in the home or a circuit in the wall is leaking electricity. Forcibly sending electricity will not only burn home appliances, but may also cause fires or cause electric shock to family members. This article will give you popular science on the working principle of leakage circuit breakers, common causes of tripping, and how to troubleshoot safely.

Core science: No-fuse switch vs. leakage circuit breaker

In distribution boxes, we often see two types of switches, with completely different functions:
1. No-fuse switch (NFB, No-Fuse Breaker): This is mainly used to protect "lines and electrical appliances." Its principle is to detect "current size". When too many high-power-consuming electrical appliances (such as a microwave oven and a hair dryer are shared) are plugged into the same circuit, causing the total current to exceed the rated value (such as 20A), or a short circuit occurs, the switch will trip to prevent the wires from overheating and melting, causing a fire.
2. Earth Leakage Circuit Breaker (ELCB, Earth Leakage Circuit Breaker): This is mainly used to protect "personal safety". Its principle is to detect "current balance". Under normal circumstances, the current flowing into an appliance should equal the current flowing out. However, if the electrical appliance gets damp or the internal wires are damaged, part of the current flows through the shell to the earth (or the human body), resulting in a slight imbalance between the inflow and outflow (usually as long as a leakage of more than 30mA is detected within 0.1 seconds), it will instantly trip and cut off the power supply to avoid fatal electric shock to the human body. Therefore, leakage circuit breakers are usually installed on circuits that are humid and easily exposed to moisture, such as kitchens, balconies, bathrooms, and water heaters.

The four main reasons why the leakage circuit breaker frequently trips

When the leakage circuit breaker trips, there are usually the following possibilities:
1. Aging of the internal insulation of the electrical appliance: This is the most common situation. The heating wires and motor insulation inside old appliances (such as old refrigerators, drinking machines, washing machines, or electric water heaters) are aging and damaged, causing current to leak to the metal casing.
2. Humid environment leads to moisture intrusion: Taipei and New Taipei areas are humid and rainy, and air reflux is more common during the rainy season. If the splash cover of the washing machine socket installed on the balcony or the toilet socket in the bathroom is damaged or there is condensation, it will easily cause a small leakage and cause the circuit breaker to trip.
3. Aging wires and pipes in the wall or rat bites: The inside of the walls of old apartments may be damp due to long-term wall cancer, causing water to enter the wire pipes; or the PVC insulation coating of the wires may be chewed by mice, and the exposed metal wires may touch the damp cement wall, causing circuit leakage.
4. The circuit breaker itself is damaged: Any electronic part has a lifespan. The average service life of an earth leakage circuit breaker is approximately 10 years. If it ages, the internal spring metal fatigues, or the test circuit is damaged, it may become overly sensitive and cause frequent "false trips."

"Five steps" for safe self-checking of leakage

When you encounter a leakage circuit breaker that trips and cannot be pushed back, please follow the following steps to conduct a safety check:
Step 1: Unplug all plugs in the circuit. Confirm the area controlled by the trip switch (such as the balcony and bathroom), and unplug all electrical appliances in this range (washing machine, water heater, flush toilet, hair dryer, etc.). Note that just turning off the electrical switch is not enough, you must "unplug" it.
Step 2: Reset the circuit breaker. First push the trip switch all the way down (reset switch), and then push it up to the "ON" position. If the switch can be pushed up smoothly and does not trip again, it means "the circuit in the wall is normal" and the problem lies in "an electrical appliance that was just unplugged".
Step 3: Plug in the electrical appliances one by one for testing. Plug in the appliances you just unplugged "one at a time" and turn them on. If the circuit breaker immediately pops open when you plug in an electrical appliance (such as a washing machine), then there is no doubt that the electrical appliance is the culprit of the leakage. Please send the appliance for repair or replacement.
Step 4: If the power still trips after unplugging all plugs, the problem is with the wiring or circuit breaker. If after unplugging all electrical appliances, the switch still jumps immediately when pushed up, it means "the wires in the wall are leaking" or "the leakage circuit breaker itself is broken." At this time, please keep the switch in the "OFF" state immediately, do not push it repeatedly, and seek help from a professional plumbing company.
Step 5: Regular self-testing. There is usually a yellow or white "TEST" button on the earth leakage circuit breaker. It is recommended to press it once a month when there is power. If the switch trips immediately after being pressed, it means that the function is normal; if there is no response after pressing the switch, it means that the circuit breaker is damaged and must be replaced immediately.

Replacement of earth leakage circuit breaker and water and electricity maintenance prices in Shuangbei

When a plumber is required to come to the house to handle the work, the reasonable prices in Taipei are as follows:
* About NT$ 500 to NT$ 1,500 (If the problem is found and the technician is decided to perform the work, the inspection fee will usually be deducted from the project cost).
* The cost of replacing a leakage circuit breaker from a single well-known brand (such as Shilin Electric, Taian, etc.) is approximately NT$ 1,500 to NT$ 2,500.
* If the wiring inside the wall is aged and re-wired, the cost will depend on the length and construction difficulty, usually ranging from NT$ 2,000 to NT$ 5,000.