Reasons for the Neutral Wire Being Energized in the Household Distribution Box

# 1. Open Circuit of the Neutral Wire (The Most Common Reason)

   - **Phenomenon**: The neutral wire is broken at a certain point, which prevents the current from

 returning through the neutral wire. The neutral wire after the break point forms a loop with the live

 wire, making the neutral wire energized.

   - **Inspection**:

     - Check whether the neutral wire terminals in the distribution box are loose or oxidized.

     - Use the resistance range of a multimeter to measure section by section whether the neutral wire

 is conducting (in the power-off state).

     - Check whether there is a break in the neutral wire in the branch circuits such as sockets and lamps.

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#### 2. Reversed Connection of the Neutral Wire and the Live Wire

   - **Phenomenon**: The positions of the neutral wire and the live wire are interchanged, resulting in

 the neutral wire actually carrying the phase voltage.

   - **Inspection**:

     - Use a voltage tester or a multimeter to check whether the neutral wire holes of sockets and switches 

are energized.

     - Check whether the wiring of the circuit breaker in the distribution box is correct (for example, the 

neutral wire of NXB-63C40 should be connected to the N pole).

#### 3. Unbalanced Load (In a Three-phase System)

   - **Phenomenon**: The uneven distribution of three-phase loads leads to an excessive current in the 

neutral wire and an increase in the potential of the neutral wire.

   - **Inspection**:

     - Check whether the three-phase electrical equipment is evenly distributed.

     - Use a clamp ammeter to measure whether the current in the neutral wire is abnormal.

#### 4. Equipment Leakage or Insulation Damage

   - **Phenomenon**: The insulation inside the electrical appliance ages, and the current leaks to the outer

 shell and is conducted through the neutral wire.

   - **Inspection**:

     - Disconnect the electrical loads one by one and observe whether the neutral wire returns to the

 non-energized state.

     - Use an insulation resistance meter (megohmmeter) to check whether the insulation resistance of 

the electrical appliance meets the standard (≥0.5MΩ).

#### 5. Fault in the Earthing System

   - **Phenomenon**: The earthing resistance of the neutral wire is too large (such as corrosion of the 

earthing body or loose connection), resulting in an increase in the potential of the neutral wire.

   - **Inspection**:

     - Measure the earthing resistance (it should be ≤4Ω).

     - Check whether the connection between the earthing wire and the neutral wire is firm.

#### 6. Internal Fault of the Distribution Box

   - **Phenomenon**: The contacts of the circuit breaker are ablated, the neutral wire terminals are loose,

 or the internal insulation is broken down.

   - **Inspection**:

     - Check whether there are signs of burning on the appearance of the circuit breaker.

     - Tighten all the wiring terminals again after powering off.

#### Safety Tips

1. **Power-off Operation**: Be sure to disconnect the main power supply before inspection to avoid 

the risk of electric shock.

2. **Professional Inspection**: If it involves complex circuits or uncertain operations, it is recommended

to contact a licensed electrician.

3. **Equipment Protection**: Regularly check the insulation performance of electrical appliances and

 install a residual current operated circuit breaker (such as NXBLE-63C40).

**Example Inspection Process**:  

Power off → Check the neutral wire terminals → Measure the conductivity of the neutral wire → Test 

the insulation of the load → Check the earthing system → Verify the voltage with a multimeter after

 restoring the power supply.