[Farewell to the Hell of Electricity Jumping] Does the power jump when you turn on the microwave oven in the kitchen? Popular science on "dedicated circuit" planning, wire diameter specifications, and Shuangbei water and electricity modification estimates for old apartments in Taiwan

Kitchen Power Trip Nightmare: Why can’t high-power appliances be turned on at the same time?

In the greater Taipei area, after many homeowners move into beautifully decorated old apartments or newly purchased second-hand houses, the most common moment of life collapse is when cooking in the kitchen: when the air fryer is baking ingredients and the microwave oven starts to heat soup, if you accidentally press the quick boiler to prepare tea, you will hear a "pop" from the power strip at the entrance, and the whole family will instantly fall into darkness. Many people wonder: Why is the battery capacity still so poor even though the interior decoration has just been completed? When traditional old apartments were built, most of the kitchens only had 1 or 2 sets of shared socket circuits planned. With the increasing popularity of modern kitchen appliances, high-power "heating appliances" such as microwave ovens, water heaters, IH induction cookers, toasters and electric cookers are concentrated in the same branch circuit. If the current easily exceeds the safe load limit of the wire, the overload protection of the fuseless switch will be activated.

Why does the power trip? Popular science about the physics of overload protection

To understand the cause of power trip, we need to understand the current calculation in the circuit (power P = voltage V × current I).
In Taiwan, the general residential single-phase two-wire socket voltage is 110V. The non-fuse switch (NFB) rating of a conventional distribution box assigned to a general outlet circuit is typically 15 Amperes (A). This means,(110V × 15A = 1650W).
Let’s take a look at the power of commonly used kitchen appliances:
- The power is approximately between 1,200W to 1,400W (approximately 11A - 12.7A).
- Power ranges from approximately 1,000W to 1,200W (approximately 9A - 11A).
- Power ranges from approximately 800W to 1,000W.
It can be clearly seen from the data that if the "air fryer (1300W)" and "microwave oven (1100W)" are plugged into the same circuit at the same time, the total wattage reaches 2400W and the current is as high as 21.8A, far exceeding the safety upper limit of 15A. The bimetallic piece inside the switch will bend due to high heat due to excessive current, and will automatically trip and cut off the power supply to prevent the wires from melting and burning due to high temperature and causing fires.

Wire diameter specifications and safe carrying current of dedicated circuits (dedicated circuits)

In order to solve the overload problem of high-power electrical appliances, the only formal solution is to set up a "dedicated circuit" for high-power-consuming appliances in the kitchen, that is, to pull a dedicated wire directly from the distribution box to a single socket without sharing it with other electrical appliances. In Taiwan's hydropower practice, the wire diameter of special circuits has strict national standards and regulatory requirements:
1. Conventional socket circuit: The common wire diameter is . Its safe carrying capacity when wired in a pipe is about 19A, so the distribution box end will be equipped with a 15A or 20A fuseless switch. This line is suitable for refrigerators (low power consumption at all times), range hoods or general small household appliances.
2. High-power dedicated circuit in the kitchen: For air fryers, water wave ovens, and IH induction stoves, it is strongly recommended to use copper wires with specifications . The safe current carrying capacity of the 5.5mm² wire can reach 25A to 30A when passing through the pipe. The distribution box end needs to be equipped withIt can carry electrical loads of up to 3,300W, even when starting a high-power instant boiling kettle.

Construction difficulty and valuation of dedicated kitchen connections in old apartments in Shuangbei

In the greater Taipei area, when many old apartments are planning to renovate their kitchens, the cost of the project depends on the "pipeline direction" and "whether walls and bricks need to be laid":
Construction method one: original pipeline replacement and threading (non-destructive construction method)
- If the original hidden pipe (CD pipe or iron pipe) in the old apartment has enough space inside the wall, and the pipe is not deformed or blocked, the plumber can use a threader to pull out the old 1.6mm or 2.0mm wires and re-thread a new set of 2.0mm or 5.5mm² wires as a special return.
- Shuangbei master's single-circuit return (including Shihlin Electric fuseless switch + 5.5mm² Nanya or Taidian wire + wiring salary + 20A/30A socket panel) including work and materials is about NT$ 3,000 to NT$ 4,500 / circuit. If the pipelines are smooth and multiple dedicated circuits are replaced together, the cost per circuit can be reduced to NT$ 2,500 to NT$ 3,500.
Construction Method 2: Cut trenches, build walls and bury hidden pipes (drilling method)
- If the pipes in the old apartment have been blocked, or there are no pipes to run at all, it is necessary to cut trenches in the walls and bury PVC pipes, and then carry out soil filling, soil removal and painting. This method is the most labor-intensive and is often used in conjunction with the whole-room water and electricity redrawing project.
- Including wall construction, buried pipes, wire pulling, and cement repair, the cost of each dedicated circuit is approximately NT$ 6,000 to NT$ 10,000 / circuit (excluding large-area painting fees).

Commercial acquisitions and businessmen’s long-term asset thinking: Kitchen electricity quality is an indicator of real estate DOM and premium

For commercial investment businessmen who specialize in acquiring medieval houses in Shuangbei for exquisite renovation and then reselling them to middle-class families (Flip), or converting whole-floor apartments into high-end co-living suites, . Modern urban buyers and high-end tenants have high requirements for quality of life, and water heaters and IH induction furnaces have become standard equipment for middle-class families. If the property is beautifully renovated, but the buyer discovers after moving in that the power goes out whenever he is cooking, it will not only cause serious sales disputes, damage the business goodwill of the businessman, but may even require compensation or deduction of the balance payment. When planning the renovation project, the businessman pre-calculates NT$ 10,000 - NT$ 20,000 in the budget, proactively plans three independent kitchens, and emphasizes the "modern kitchen heavy-electricity worry-free system" in the sales promotion, which can greatly enhance the competitiveness of the object. Compared with ordinary old houses in the same area, it can create5% to 8% House price premiumand significantly shortening the days to sell a house, this is shrewd real estate value-added investment.

The Ministry of Economic Affairs' latest "Regulations on Consumer Electrical Equipment Installation" and the key points of electricity safety in old houses

Due to the popularity of high-power household appliances (such as air fryers, microwave ovens, dishwashers, instantaneous electric water heaters, and IH furnaces) in recent years, the Energy Administration of the Ministry of Economic Affairs has revised the "Regulations on Consumer Electrical Equipment Installation" many times to strictly require the diversion and protection mechanisms of residential electricity circuits. Statistics show that more than 30% of building fires in Taiwan are caused by electrical factors, among which "old wire insulation deteriorates and short circuits", "socket contacts are oxidized and loose, poor contact" and "non-fuse switch (NFB) overloaded and failed to trip" are the three main fatal causes.

Old apartments in Shuangbei that are more than 30 years old have a total original designed power capacity of only 30A to 40A, and several rooms often share the same 1.6mm or 2.0mm circuit. In the modern standard safety configuration, kitchen electrical cabinets, bathroom equipment, and air-conditioning and heating machines must all be equipped with 5.5mm² dedicated circuits (single circuit and single socket). It is recommended that the main switch box be upgraded to a busbar (Busbar) integrated distribution board, and the total amperage is increased to 75A or 100A (a qualified electrical appliance contractor needs to be entrusted to Taipower to review the additional power capacity).

Residential electricity self-test and regular inspection checklist

• Appearance and temperature of the socket: Touch the outer cover of the commonly used socket lightly with the back of your hand. If it feels lukewarm or if you find that the plastic socket is yellowed and charred, or the plug is loose and shaking after being plugged in, it means that the internal copper plate clamping force is exhausted or the contact resistance is too high, and you should immediately cut off the power and replace it.
• Regular testing of leakage circuit breakers (ELCB): For leakage circuit breakers in humid places such as balconies, bathrooms, and kitchen sinks, regulations require that the "TEST button" on the switch be pressed once every 1 to 3 months to confirm that it can automatically trip and cut off the power supply instantly.
• Serial connection and overloading of extension cords are strictly prohibited: Extension cords should be purchased with 2.0mm thick wire diameter products that have CNS certification and automatic overload power-off protection. Do not share the same extension cord with high energy-consuming appliances to ensure zero hidden danger to life and property at home.