We will now learn the design characteristics of safe electrical equipment. Let us being by understanding what is examination of equipment.

Examination of Equipment

It is important to examine electrical equipment, which may cause serious physical hazards. It ensures that the equipment is free from recognized hazards. Consider the following important points for the safety of equipment.

• Suitability of equipment is identified according to the labeling and specification

• Mechanical strength and durability

• Electrical insulation

• Heating effect under the condition of the area

• Arcing effect

• Practical safeguarding of employees

Use of Electrical Equipment

The electrical equipment should be installed in accordance with the given instructions including the type, size, voltage, current capacity and specific use. The devices must indicate the purpose only after it is reviewed and the arrangement has been made for it to fulfill the purpose. Even a small device has its own importance. For example, disconnection of a switch enables a circuit to be opened and stops the flow of electricity. The equipment must withstand weather, chemicals, heat, corrosion or any hazardous environment.

Working with Electrical Equipment

It is very important for a person working with electrical equipment to be qualified to work on the equipment. Working on live parts always creates hazards without using the personal protective equipment. Clean the cutting material on the floor after the work. There must be a storage room to keep the equipment safely. The workspace must be wide and well ventilated. An electrician must follow the standards of NEC, NBC, NFPA, and IEC, etc.

Safety Requirement for Electrical Equipment

Verification and testing will guarantee the safety and quality of the equipment. Confirmation of equipment in accordance with the product standards is the prime importance of an installation. The grounding of equipment is necessary to divert the fault current, which will be permanent and continuous. High temperature may lose the continuity of ground-fault path. So Ground Fault Circuit Interrupter must be used to prevent injury from electrical wiring. It would provide an extra protection to the device. The breaking of insulation of cable occurs simply by aging. This may lead to shocks, burns and fire. So periodic maintenance of electrical equipment is required. The maintenance predicts and prevents the damage. The equipment needs to be protected from lightning by installing the surge protection system.

The best process of protection is “automatic disconnection of supply” which can be provided by the implementation of system earthing. An electrician should have sufficient knowledge about the standardized system (TT, TN and IT system). Protection against overload, short circuits and earth leakage current can also protect the device from damage. Each item must be well insulated and packaged.

Standards for Designing Electrical Equipment

There are some internal standards that need to be followed while designing the electrical equipment. The standards are as follows −

• International Electro-technical Commission (Europe)

• Institute of Petroleum (UK)

• International Standards Organization (worldwide)

• British Standards Institution (UK)

• American Petroleum Institute (USA)

• Engineering Equipment and Materials Users Association (UK)

• Electricity Council (UK)

• Institute of Electronic and Electrical Engineering (USA)

Questions

1. Which of the following is not a fact for the safety of equipment?

a) Mechanical strength and durability

b) Electrical insulation

c) Color of equipment

d) Heating effect under the condition of the area

Ans: c

Explanation

To examine the safety equipment, mechanical strength, durability, electrical insulation and heating effect under the condition of the area are a few points that need to be considered. However, it does not depend on the color of the equipment.

2. Which device prevents injury from electrical wiring?

a) MCB

b) ACB

c) Switch

d) GFCI

Ans: d

Explanation

The Ground Fault Circuit Interrupter senses the fault and temporarily breaks down the circuit within few milliseconds. This prevents injury from electrical wiring.

3. Which organization’s standard does every manufacturer follow to design electrical equipment?

a) IEC

b) ISO

c) IEEE

d) All of the above

Ans: d

Explanation

A manufacturer must focus on the specification, type, safety, testing, application and quality of equipment. Therefore, the manufacturer must choose the standards of International Electro-technical Commission (IEC), International Standards Organization (ISO) and Institute of Electronic and Electrical Engineering (IEEE) to design electrical equipment.