Showing posts with label wiring installation. Show all posts
Showing posts with label wiring installation. Show all posts

Monday, January 18, 2016

Industrial Control Wiring Guide

Wires and preparation for control wiring

Electrical equipment uses a wide variety of wire and cable types and it is up to us to be able to correctly identify and use the wires which have been specified. The wrong wire types will cause operational problems and could render the unit unsafe.

Such factors include:
  • The insulation material;
  • The size of the conductor;
  • What it’s made of;
  • Whether it’s solid or stranded and flexible.
These are all considerations which the designer has to take into account to suit the final application of the equipment.
Industrial Control Wiring GuideA conductor is a material which will allow an electric current to flow easily. In the case of a wire connection, it needs to be a very good conductor. Good conductors include most metals. The most common conductor used in wire is copper, although you may come across others such as aluminium. An insulator on the other hand is a material which does not allow an electric current to flow. Rubber and most plastics are insulators.

Insulation materials

Wires and cables (conductors) are insulated and protected by a variety of materials (insulators) each one having its own particular properties. The type of material used will be determined by the designer who will take into account the environment in which a control panel or installation is expected to operate as well as the application of individual wires within the panel.


Preparing wireAs part of the insulating function, a material may have to withstand without failing:
  • Extremes of current or temperature;
  • A corrosive or similarly harsh environment;
  • Higher voltages than the rest of the circuit.
Because of these different properties and applications, it is essential that you check the wiring specification for the correct type to use.





Click here to access the full guide


Thursday, November 12, 2015

Connections For Testing Insulation Resistance Of Electrical Equipment

Testing Insulation Resistance //

The following schemes show how to connect a Megger insulation tester to various types of electrical equipment. The schemes also show in principle how equipment must be disconnected from other circuits before the instrument is connected.
Connections For Testing Insulation Resistance Of Electrical Equipment
These illustrations are typical and will serve as guides for testing insulation resistance of practically all types of apparatus and conductors. Before proceeding with tests, read the part on Preparation of apparatus for test at the bottom of this article.

REMEMBER! The Megger insulation resistance tester measures whatever resistance is connected between its terminals. This may include series or parallel leakage paths through insulation or over its surface.

Electrical equipment to test //

  1. AC Motors and Starting Equipment
  2. DC Generators and Motors
  3. Wiring Installation
  4. Appliances, Meters, Instruments and Other Electrical Apparatus
  5. Control, Signaling and Communication Cables
  6. Power Cables
  7. Power Transformers
  8. AC Generators

Important //


1. AC Motors and Starting Equipment

Connections for testing the insulation resistance of a motor, starting equipment and connecting lines, in parallel. Note that the starter switch is in the “on” position for the test. It is always preferable to disconnect the component parts and test them separately in order to determine where weaknesses exist.
Testing the insulation resistance of a motor
 
 
 
Figure 1 – Testing the insulation resistance of a motor
 
 
Click here to access the full article