Container House Electric Meter Connection

The connection of the electric meter for a container house requires selecting the appropriate wiring method based on the actual type of electricity used (single-phase/three-phase) and strictly adhering to safety regulations.

I. Single-Phase Electric Meter Wiring Methods

Single-phase electric meters are suitable for 220V household electricity scenarios. The wiring steps are as follows:

1. Direct Connection Method

   • Ensure that the load power is within the rated range of the electric meter (to avoid excessive current burning out the coil).
   • The electric meter usually has 4 connection terminals (for some models, only 4 external connection terminals are required after internal short-circuiting). Connect the wires in one of the following ways:
     • Method 1: Terminals 1 and 3 are connected to the incoming wires (live wire L and neutral wire N), and terminals 2 and 4 are connected to the outgoing wires.
     • Method 2: Terminals 1 and 2 are connected to the incoming wires, and terminals 3 and 4 are connected to the outgoing wires.
   • Key Requirement: The live wire must be connected to the current coil terminal of the electric meter (the specific terminal should refer to the wiring diagram on the meter cover).

2. Connection via Current Transformers (for high-current scenarios)

   • The current transformer (CT) is connected in series with the live wire, and the secondary-side output is connected to the current coil of the electric meter.
   • There are two wiring situations:
     • If terminals 5 and 1 inside the electric meter are not disconnected: The K2 terminal of the current transformer is prohibited from being grounded.
     • If terminals 5 and 1 inside the electric meter are disconnected: The K2 terminal of the current transformer must be grounded, and the voltage coil is connected to both ends of the power supply.
   • Actual Electricity Calculation: Electric meter reading × current transformer ratio.

II. Three-Phase Electric Meter Wiring Methods

Three-phase electric meters are suitable for 380V industrial or high-power scenarios. The wiring methods include direct connection and connection via current transformers:

1. Direct Connection (current < 100A)

   • Connect the three-phase live wires (L1, L2, L3) to the incoming terminals of the electric meter (usually labeled 1, 3, and 5), and connect the neutral wire (N) to the neutral terminal (labeled 7 or N).
   • Note: The phase sequence must be correct (L1→L2→L3); otherwise, it will cause incorrect meter counting or equipment abnormalities.

2. Connection via Current Transformers (for high-current scenarios)

   • The current transformers are connected in series with each phase live wire, and the S1 and S2 terminals on the secondary side are connected to the current coil of the electric meter.
   • Wiring Example:
     • For phase A, the S1 terminal of the current transformer is connected to terminal 1 of the electric meter, and the S2 terminal is connected to terminal 3; for phase B, S1 is connected to terminal 4, and S2 is connected to terminal 6; for phase C, S1 is connected to terminal 7, and S2 is connected to terminal 9.
     • The voltage wires are directly sampled from the power supply, with phases A, B, and C connected to terminals 2, 5, and 8 of the electric meter respectively, and the neutral wire connected to terminal 10.
   • Key Requirement: The wire-threading direction of the current transformers must be consistent (P1→P2); otherwise, the electric meter will run backward; the three-phase voltage wires and current wires must not be mixed up.

III. General Safety Regulations

1. Environmental Requirements: The electric meter should be installed in a dry, vibration-free, and strong magnetic field-free location, and the metal meter box should be reliably grounded.
2. Wiring Inspection: Cut off the power and verify that the circuit is de-energized before wiring; after wiring, check the phase sequence, polarity, and screw tightness.
3. Tilt Control: The electric meter should be installed vertically, with a tilt of no more than 2° in the front, back, left, and right directions to avoid measurement errors.
4. Wire Specifications: For connection via current transformers, use copper wires with a cross-sectional area of no less than 2.5mm². The voltage wires and current wires should be color-coded for differentiation.