Page 249 - Electrician - TT (Volume 2)

ELECTRICIAN - CITS

Fig 34

Parts list
Although not a drawing in itself, in fact it may be part of a drawing. The parts list gives vital information:

• It relates component types to circuit drawing reference numbers.
• It is used to locate and cross refer actual component code numbers to ensure you have the correct parts to
commence a wiring job.
Example:

Parts list

Ref Bin Description Code

C81 A3 KM Circuit Breaker PKZ 2/ZM-40-8
MC A4 KM Contactor OIL 2AM 415/50

TOL A4 KM Over load Relay ZI-63

Componets used in control wiring (Fig 35)

Component mounting rails
• These rails - sometimes called ‘DIN rails’ - are metal strips with a special profile allowing components and sub-
assemblies to be fixed onto a chassis plate without using screws.

There are two basic profiles available in two common sizes:
• Symmetrical or ‘top hat’.
• Asymmetrical.
These are cut to the required length and then screwed or bolted to the chassis before any wiring begins.

Plastic trunking
• This is one form of cable ducting and used to carry the wiring between components. It pro¬vides protection
while keeping the wires and cables neat.
Connector blocks

Clip-on terminals
Terminal blocks of various sizes and types provide a very common way of connecting the control assembly to the
outside world.

• For most power controllers the main connections will be made via these screw clamp terminal units.

236

CITS : Power - Electrician & Wireman - Lesson 93-100