![[Grounding and Leakage Safety in Old Houses] My old apartment has no ground wire (G wire) and my scalp feels numb after taking a shower? Whole-house three-wire system heavy pull, induction lightning protection and moisture loop ELCB configuration blind area](/images/screwdrivers-1073515_1280.webp)
Invisible risk of electric shock in old apartments: Is the faucet numb when you touch it while taking a bath?
In many apartments over 30 years old in Taipei City and New Taipei City, many residents have had this horrifying experience: when their hands touch the metal faucet while taking a shower, or when they touch the refrigerator casing with the door open with bare feet, their fingers will feel a faint tingling sensation (leakage inductance); or the high-end gaming computer host or smart toilet seat that they just bought at home will be electrocuted when the metal casing is touched. Many plumbers will comfort and say: "This is normal static electricity!" But in fact,this is a very dangerous leakage warning! This means that the electrical system in your home completely lacks "Grounding Wire (G wire)". When the internal insulation of home appliances ages and leaks, the current cannot be directed to the earth, and the human body becomes the only conductor!
Fact check: Taiwan’s regulations and the historical blind spots of “two-tier system vs. three-tier system”
Before Taiwan revised the "Regulations on Consumer Electrical Equipment Installation" in 1999, when constructing residential wiring, builders generally adopted the traditional "two-wire system (single-phase two-wire 110V: including a live wire L and a water wire/neutral wire N)", and there was no green ground wire (G) in sockets and electrical boxes.
All modern qualified three-hole sockets and high-power home appliances (dishwasher, microwave oven, electric water heater, computer host) are equipped with round grounding pins. Many plumbers or homeowners who don't understand safety will use an "adapter (two-pin to three-pin)" to directly cut off the grounding pin on the socket for convenience. This is tantamount tounplugging the life-saving defense line of household appliances with your own hands! Once the insulation of the heating pipe inside the electric water heater is damaged, bathers will face fatal high-voltage electric shock accidents.
The radical cure: Re-drawing and grounding system reconstruction of the whole house's "three-wire system"
To completely eliminate the risk of electric shock in old houses, the following three electrical and mechanical projects must be strictly carried out during renovation of water and electricity:
- Re-draw the electrical wiring throughout the house and introduce an independent green grounding wire (G): Unplug the old wires in the wall pipes and re-thread them through Pacific or Daya-certified wires. Each circuit must be equipped with three wires: Hot wire (red/brown), Neutral wire (white/blue), Ground wire (green). The ground terminal of the three-hole socket must be connected to the green ground wire.
- The main distribution box is equipped with a copper grounding busbar (Grounding Busbar): An independent pure copper grounding busbar must be installed in the distribution box to collect the green grounding wires of all circuits in the room.
- Connect the building structure to the ground or drive in an independent grounding rod: The main grounding wire of the distribution box must be connected to the steel bars in the columns of the building structure (building structural grounding system). If it is an independent skylight or a first-floor apartment, a "copper-clad steel grounding rod (Grounding Rod)" with a depth of 1.5 to 3 meters needs to be driven outdoors to ensure that the grounding resistance meets regulatory requirements (usually less than 50 ohms Ω).
- High-sensitivity leakage circuit breakers (ELCB) must be installed in humid areas: According to regulations, special circuits for bathrooms, kitchens, work balconies and water dispensers must be installed at the electrical box end with a high-sensitivity ELCB leakage circuit breaker with an operating current of 15mA and an operating time of less than 0.1 seconds. Once a trace leakage occurs, the device will instantly jump out and cut off the power supply before the current harms the human body.
CapEx budget planning for grounding and wire redrawing in Shuangbei Old House
For owner-occupiers or real estate flip investors, the cost of whole-house wire redrawing and three-wire grounding is as follows:
| Engineering Project | Description of construction details and material specifications | Estimated cost (NTD) |
|---|---|---|
| Re-drawing of wires throughout the room (three-wire system) | Replace the old wire and insert it into Taidian 2.0mm/5.5mm² (fire + water + green ground wire), based on the number of square feet | NT$ 2,500 - $4,000 / square meter |
| Electrical box grounding copper bar and ELCB configuration | Installation of grounding copper bar in the main electrical box + Shihlin Electric ELCB leakage circuit breaker x4 | NT$ 8,000 - $15,000 |
| Independent grounding rod installation (through sky/first floor) | Drill a 2.5-meter copper-clad steel grounding rod outdoors and measure the grounding resistance to be less than 50Ω | NT$ 8,000 - $14,000 |
| Total budget for grounding and pulling of 30 ping old house | Completely eliminate the risk of electric shock to the human body and damage to home appliances due to lightning strikes, creating top-level electrical safety | $83,000 - $135,000 |
Conclusion: Use three-wire grounding to build the electrical defense line of life
The numbness in the shower is by no means static electricity, but a life-or-death warning that the electrical system in an old house lacks a ground wire. When remodeling an old house in Shuangbei, you must not be satisfied with just smoothing the walls and applying beautiful paint. Adhering to the three-wire wiring system throughout the house, reconnecting the green ground wire, and installing leakage circuit breakers are insurmountable red lines to ensure the safety of your family. A compliant medieval house with a ground resistance test report is the golden cornerstone to show buyers the highest construction quality standards.
