The form (form) industrial electrical cabinets used today

In the records required to design low voltage cabinets often refer to the form (form) of low voltage cabinets. What is the form (hereinafter referred to as electric cabinet form) of low voltage cabinet? Why is it required to provide a cabinet according to form 2,3 or 4? Which form is required for the cabinet?

The following article introduces the basic concepts of low voltage cabinet form to answer some of these questions.

1. Concepts

Form of electric cabinet is a concept to regulate the separation between 3 main components in a low voltage cabinet (IEC 61439).

A: Switchgear

B: Main busbar

C: Connection point of the device

2. Classification of electric cabinet form:

Based on the separation between 3 main components, electrical cabinets are divided into 7 types of forms.

Include:

    Form 1
    Form 2a
    Form 2b
    Form 3a
    Form 3b
    Form 4a
    Form 4b.

  2.1. Function to ensure safety for operators and property

    Ensuring safety for operators and property
    The higher the level of electric cabinet form, the greater the level of safety protection
    Absolutely safe protection for operators before electric discharge phenomenon
    Better protection of damage of equipment in cabinets and equipment outside the fire risk.

  2.2. Functions ensure continuity during operation

The higher the level of the Cabinet form, the faster the replacement and repair flexibility.

3. Structure of electric cabinet form

3.1 Electrical cabinet Form 1

A: Switchgear

B: Main busbar

C: Connection point of the device

D: Cabinet

- Electric cabinet Form 1 does not have a partition between switchgear and main busbar and connection point of the device

- There is no partition in the cabinet

- Form 1 electrical cabinet is rarely used because it does not guarantee safety for operators and equipment when there is a risk of an incident.

3.2. Electrical cabinet Form 2a

E: Partition partition for protection

Function blocks are individually protected by partitions with the main busbar and the connection point of the device.

3.3. Electrical cabinet Form 2b

- Function blocks with the connection points of the device are partitioned separately with partitions with the main busbar;
- Electric cabinet Form 2b is widely used for floor distribution cabinets.

3.4. Electrical cabinet Form 3a

- Each function block is partitioned separately by a partition with the main busbar and the connection point of the device.

3.5. Electrical cabinet Form 3b

- Each function block is partitioned separately by a partition with the main busbar and the connection point of the device.

- The connection point of the device is also partitioned separately by partition with the main busbar;
- Currently, Cabinet type 3b is widely used in the design of general electric cabinets for buildings, light industry.

3.6. Electrical cabinet Form 4a

Each function block together with the connection point of the device is partitioned separately by a partition with the main busbar.

3.7. Electrical cabinet Form 4b

    Each function block is individually protected by a partition with the main busbar and the connection point of the device
    The connection point of the device is also partitioned separately by partition with main busbar and function block.
    Form cabinet 4b is often used for heavy industry projects such as power plants, mineral processing plants, cement and petrochemical refineries ....
    Ensure safety for operators, equipment in cabinets and around cabinets when there is a risk of fire and explosion;
    Replace repair equipment quickly and without power cut (Pull down the function tray).