Control cabinet assembly

The assembly of the control cabinet should begin with a thorough understanding of customer requirements and electrical design standard documentation. This design phase should contain all the guidance needed to finish the assembly process. Any queries which arise during installation should be discussed and clarified with the designer.

1. Preparation of the holes in the housing.

This step should be one of the first undertaken. Sawdust and metal debris generated during cutting and drilling is most easily removed without affecting later components. Metal filings which interfere with electronic equipment (e.g. PLC or power supplies) can lead to short circuits and damage with the potential to cause danger to users.
To complete the preparation of circular holes, use a hydraulic or screw punch.

2. Installation of control and signalling equipment on the cabinet door.

Use the prepared holes to install controls and switches. Components which are sensitive to shock or which have delicate displayed should be installed later to avoid possible damage.

3. Installation of cable ducts and rails.

Use the mounting plate to position perforated ducts (available in a range of sizes) and DIN rails (usually a standard 35mm in size). Cable ducts and rails are usually available in two metre sections should be cut to the required size.

4. Installation of components.

Standard electronic components will snap to the DIN rail. Larger devices such as variable frequency drives are safer to install by screwing directly to the mounting plate.

5. Electrical connections.

For this process, ensure you have the required stripping and crimping tools. When cutting wires to length, it is safe to leave some excess for each device. This allows slight adjustment of component positions without re-running new wires.

Each end of the wires should be crimped with ferrules of the appropriate length and diameter. Some electrical design requires two wires to be connected in a chain, and the appropriate twin ferrules should be used. A twin ferrule and two single ferrules.

6. Apparatus marking.

7. External connection using a plate with cable glands.

In general, any connection to external electrical equipment is carried out via a plate located at the bottom of the cabinet. One of the last operations is to prepare the holes for cable glands in this lower plate.