how to change electrical box

To replace an electrical box (such as a power distribution box or a meter box), the corresponding solution should 

be selected according to the type and scenario. The following is a guide for replacing the **low-voltage power 

distribution box** and the **meter box** in a home scenario:

### I. Clarify the Type of Electrical Box

1. **Power Distribution Box** (Indoor, for Users): Controls the distribution of household circuits and contains

 components such as circuit breakers and residual current devices.

2. **Meter Box** (Outdoor/Public Area): Managed by the power supply company, it contains an electricity meter

 and an incoming line switch.

### II. Replace the Power Distribution Box (Indoor)

#### Applicable Scenarios: Aging of the old box, insufficient circuits, damaged switches

The steps are as follows:

#### 1. Preliminary Preparation

- **Power Off**: Turn off the indoor main power supply. If it is a concealed box, go to the meter box in the corridor 

to cut off the incoming power supply to the household.

- **Tools and Materials**: New power distribution box (of the same specification or larger size), insulated gloves,

 screwdriver, electrical tape, label paper.

- **Mark the Circuits**:

  - Before removing the old box, use **label paper** to mark the circuit of each wire (such as "Living Room Socket", 

"Kitchen Lighting").

  - Take photos to record the wiring diagram of the old box (the positions of the neutral busbar, ground busbar,

 and the incoming and outgoing wires of the circuit breaker).

#### 2. Remove the Old Electrical Box

- **Surface-mounted Box**: Directly unscrew the fixing screws and disconnect all wire connections.

- **Concealed-mounted Box**:

  1. Chip away the cement around the box body and keep the pre-embedded metal/plastic base box.

  2. If the base box is aging and needs to be replaced, the hole should be expanded simultaneously and the new

 base box should be fixed.

#### 3. Install the New Electrical Box

- **Fix the Box Body**:

  - Surface-mounted: Fix the box body to the wall with expansion screws.

  - Concealed-mounted: Embed the box body into the base box, fix the four corners with screws, and fill the gaps 

with gypsum.

- **Wiring Rules**:

  - **Phase Wire (L)**: Connect to the upper port of the circuit breaker and install it corresponding to the original

 circuit.

  - **Neutral Wire (N)**: Connect to the neutral busbar centrally and keep it insulated.

  - **Ground Wire (PE)**: Connect to the ground busbar to ensure reliable grounding.

  - *Note: The neutral wire and the ground wire are strictly prohibited from being mixed!*

#### 4. Testing and Acceptance

- **Check before Powering On**: Use a multimeter to measure the resistance between the phase wire, the neutral wire, 

and the ground wire. There should be no short circuit (resistance > 0.5MΩ).

- **Circuit-by-circuit Testing**: Close the switch for each circuit one by one, check whether the corresponding electrical

 appliances work properly, and whether the residual current device trips sensitively.

### III. Replace the Meter Box (Outdoor/Public Area)

#### Applicable Scenarios: Damage to the box body, malfunction of the electricity meter, insufficient capacity

The steps are as follows:

#### 1. Contact the Power Supply Company

- Call **95598** or apply at the local business hall, and state the reason for replacement (such as aging, potential 

safety hazard).

- The power supply company will send personnel to conduct on-site inspections to confirm whether the replacement 

conditions are met.

#### 2. Cooperate with the Construction

- **Power Off**: The power supply company disconnects the incoming power supply to the electricity meter.

- **Remove the Old Meter Box**: Professional personnel will remove the old meter, terminal blocks, and the box

 body.

- **Install the New Meter Box**:

  - Replace it with a meter box of the same specification, or upgrade it to a smart meter box with remote meter 

reading function.

  - The wiring should comply with the power supply specifications to ensure that the markings of the phase wire, 

neutral wire, and ground wire are clear.

#### 3. Acceptance and Power Restoration

- The power supply company tests the meter reading and the insulation of the wiring. After confirming that there 

are no errors, the power supply will be restored.

- Receive the user number and usage instructions of the new electricity meter.

### IV. Key Precautions

1. **Safety First**:

   - Operate with the power off throughout the process. Ensure that there is no voltage before testing the electricity

 (test with a voltage tester).

   - Wear insulated gloves in a humid environment and avoid touching the wires with bare hands.

2. **Circuit Handling**:

   - If the old wires are aging, they need to be replaced simultaneously. It is prohibited to directly splice the wires 

in the power distribution box (a terminal block should be used).

   - For high-power circuits such as air conditioners and water heaters, wires with a cross-sectional area of more

 than 4mm² should be used separately.

3. **Compliance**:

   - The meter box is the asset of the power supply company. Users are not allowed to replace it privately, otherwise

 they may face penalties.

   - After the replacement of the indoor power distribution box, it should comply with the Code for Low Voltage Power

 Distribution Design (GB 50054).

### V. Answers to Common Questions

**Summary**: The indoor power distribution box can be replaced by oneself (it is recommended to be operated by an

 electrician), and the meter box needs to contact the power supply company. After the replacement, the safety of the

 circuit should be tested to ensure reliable power supply.