Installation Specifications For Distribution Boxes

The installation specifications of distribution boxes are multi-faceted and multi-standard. The core goal is to ensure the safety of the power system and the safety of personnel operations. The following are the main installation specifications for reference:

I. Installation location height and environmental requirements
1. Position principle:
It should be close to the load center to facilitate operation, maintenance and inspection, and should not be installed in a place that affects the evacuation of personnel and is prone to collision or severe vibration.

2. Height standard:
Floor-standing type: The bottom of the box should be 100mm ~ 200mm higher than the ground, usually made of concrete foundation or steel base.

Wall-mounted:
Lighting distribution box: The bottom edge of the box is generally 1.5 meters to 1.8 meters from the ground, and the common distance is 1.5 meters, which is easy to operate.
Meter box: Usually the center is 1.6 meters to 1.8 meters away from the ground, which facilitates meter reading.
If there are no special requirements, it is appropriate for the center of the box to be about 1.6 meters from the ground.

Embedded: For boxes embedded in the wall, the panel should be close to the wall, and the surrounding gaps should be filled with mortar, but the box should not be squeezed or deformed.

3. Environmental conditions:
No flammable, explosive, corrosive gas or dust, no strongly conductive dust.
The ambient temperature generally does not exceed 40°C, and the humidity should not be too high.
It is strictly prohibited to install it in bathroom zones 0 and 1 or in humid places prone to condensation. If it must be installed in a humid place, a moisture-proof distribution box should be used with a protection level of not less than IP54.

II. Enclosure and Component Requirements

1. Enclosure Material: The distribution box should be made of cold-rolled steel plate with a thickness ≥1.5mm or flame-retardant insulating material.

2. Component Arrangement: Components must be mounted on metal or flame-retardant insulating boards; circuit breakers should have insulating partitions between phases, and exposed live parts must have protective plates.

3. Enclosure Function: The enclosure should be rainproof and dustproof, and the IP protection rating must meet environmental requirements.

III. Electrical Wiring and Grounding Requirements

1. Enclosure Grounding: The metal enclosure, mounting plate, and metal casing must be reliably grounded through a PE terminal block. The enclosure door should be bridged with yellow/green bicolor soft copper wire.

2. N and PE Lines: An N-line terminal and a PE-line terminal block must be installed inside the enclosure. The N-line terminal block must be insulated from the metal mounting plate.

3. Wire Specifications: Connecting wires must use copper core wires, color-coded according to standards: L1 yellow, L2 green, L3 red, N light blue, and PE yellow-green.

4. Cable Inlet/Outlet: Cable inlets/outlets should be located at the bottom of the enclosure. Insulating sleeves should be installed at the conduits, and cable heads should be securely fixed. N and PE wires from different circuits must not be connected to the same hole on the terminal block.