Revised Standard from Last Update.

FOREWORD

PART 1 GENERAL AND COMMON ASPECTS

Electricity has become an integral and inevitable part of everyone’s life. The progress and technological advancement of modern society depends on electricity. However it is important to remember that, if electrical installations are not handled according to relevant guidelines, it could be harmful. Therefore, electrical installations require adequate planning right from concept stage to layout and designing, selection of proper equipment, their installation and their maintenance. Fundamental aspects of installation practice are common for most of the types of electrical installations. Part 1 of the National Electrical Code of India covers these aspects under its various Sections.

There are several Indian Standards existing on different aspects of electrical installation practice. An attempt has been made through this Code to refer to the present good practices and guidelines. A reference has also been made to product standards in order to inform the user of the Code about the availability and desirability to use them.

Aspects concerning specific occupancies are covered in other Parts and Sections of this Code. The fundamental principles of installation practice covered under Part 1 of this Code generally apply, unless modified or supplemented by subsequent Parts. This Part 1 would also be a useful reference for occupancies not explicitly covered by the scope of subsequent Parts of the Code.

PART 2 ELECTRICAL INSTALLATIONS IN STAND-BY GENERATING STATIONS AND CAPTIVE SUBSTATIONS

This Part 2 of the National Electrical Code of India is primarily intended to cover the requirements relating to stand-by generating stations and captive substations. Standby generating sets are generally the standby power supply source and play an important role in preserving property and lives in emergencies. Captive sub stations are intended for serving an individual occupancy. The general provisions relating to such installations are common and are detailed elaborately in this part of the code.

Generating stations covered by this Part 2 are the stand-by or emergency supply and captive substations normally housed in or around the building in question. This Code does not include the switching stations and other large generating plants that come solely under the preview of the relevant electric supply authorities even though to some extent the requirements stipulated herein could also be applicable to them.

Specific requirements if any, for generating and switching substations for individual buildings that might vary depending on the nature of the occupancy or the size of the building are enumerated in the respective sections of the Code.

In the formulation of this Code, note has been taken of the requirements stipulated in installation Codes of individual equipment as well as the fire-safety Codes for generating stations and substations. It is generally not feasible to draw very strict guidelines for the design and layout for such installations owing to the complexity of the needs of building installations and hence only the essential safety considerations are listed out for compliance. It is essential to take recourse to the assistance of local authorities for further details.

Specific requirements pertaining to stand-by generating stations and captive substations for multistoried buildings are covered in Part 3/Section 22 of this Code.

PART 3 LOW-VOLTAGE ELECTRICAL INSTALLATIONS - REQUIREMENTS FOR SPECIAL INSTALLATIONS OR LOCATIONS

This Part 3 of the code covers the requirements for electrical installations for special purposes and at special locations. It can also be classified as electrical installations in non-industrial buildings. The requirements for electrical installations in industrial buildings has been detailed in Part 4 of the code. While a majority of installations could be categorically classified as non- industrial, an industrial complex would necessarily incorporate sub-units such as offices, residential quarters and support services which are either housed or fall in the category of non-industrial buildings. The requirement stipulated in Part 3 and Part 4 of this Code would therefore require judicious application.

With the current trend in power utilization, it would also be extremely difficult to classify electrical installations based on power requirement or the voltage of supply, as large buildings for non-industrial purposes consume sufficient power to consider them at par with the consumption of light industrial establishments. It is therefore necessary to consider for initial assessment of the installation the guidelines given in Part 1/Sec 8 this Code,which are better defined than the earlier terminology used for classifying installations. Also, this part specifies the requirements for installations in certain special purposes like supplies for electrical vehicles and furniture that require special attention for safety and ease of usability.

Part 3 of this Code, therefore covers requirements for several types of special applications and non-industrial occupations. In case of typical occupancies that strictly fall into any of these, recourse shall be made to the general guidelines stipulated in Part 1.

PART 4 ELECTRICAL INSTALLATIONS IN INDUSTRIAL BUILDINGS

Electrical installation in industrial buildings requires special attention in design with a basic consideration for ‘safety at work-places’, quality and continuity of supply, energy conservation.

The layout of electrical installation should facilitate maintenance with ease and free access. Distribution shall be designed so that fault localization is possible targeting lowest down time.

Keeping in view the tariff structures depending on Time of Day (ToD), as also an economic necessity; conserving power, maintaining power factor nearest to unity, limiting harmonic effects shall be considered as important aspects.

For reliability and continuity of supply for essential/continuous operations, standby and emergency supply sources/networks shall be designed.

PART 5 OUTDOOR INSTALLATIONS

As compared to the various types of indoor installations covered in other Parts of this Code, outdoor installations are distinct in nature by virtue of their being exposed to moderate to heavy environmental conditions. In addition, electric power in outdoor installations is normally utilized for specific purposes, such as lighting or for meeting the needs of heavy machinery (for example, open cast mines). In the case of the latter, the duties would be more onerous than those normally encountered in indoor situations, thereby calling for special considerations in their design.

Keeping the above in view, Part 5 of this Code deals with installations erected outdoor. Some outdoor installations are erected to serve for a small duration of time after which they are meant to be dismantled. Such installations are called temporary installation. For convenience, and keeping other aspects of safety provisions in view, this duration is defined as not exceeding six months. Permanent outdoor installations are those which are generally in use for longer periods of time. This Part 5 of this Code basically deals with these two types of outdoor installations.

PART 6 ELECTRICAL INSTALLATIONS IN AGRICULTURAL PREMISES

This Part of the Code is primarily intended for covering the specific requirements of electrical installations in agricultural premises which include premises where livestock are present and farm produce are handled or stored. With the increase in sophistication in organizing the farm output of the country, and the use of electricity for certain essential purposes, it has been felt necessary to cover the requirements of such installations as a part of the Code.

Installations in agricultural premises are different from those covered in other Sections of the Code in that the external influences on the electrical services are quite different from those encountered elsewhere. Even though the overall power requirements for such installations would be small, the presence of livestock and other extraneous factors necessitate laying down specific requirements.

PART 7 ELECTRICAL INSTALLATIONS IN HAZARDOUS AREAS

Explosive gas atmosphere is the atmosphere where mixture with air, under atmospheric conditions, of flammable substances in the form of gas or vapour, which, after ignition, permits self-sustaining flame propagation. Area in which an explosive gas atmosphere is present, or may be expected to be present, in quantities, such as to require special precautions for the construction, installation and use of equipment is referred as a hazardous area and has to be treated in a special manner from the point of the design of electrical installation.

Many liquids, gases and vapours which in industry are generated, processed, handled and stored are combustible. When ignited, these may burn readily and with considerable explosive force when mixed with air in the appropriate proportions. With regard to electrical installations, essential ignition sources include arcs, sparks or hot surfaces, produced either in normal operation or under specified fault conditions.

PART 8 SOLAR PHOTOVOLTAIC (PV) POWER SUPPLY SYSTEMS

Solar energy is a natural resource which is, for practical purposes, free, renewable and inexhaustible and can supplement/augment the depleting fossil fuel resources. Greenhouse gases and pollutant emissions which result from fossil fuel power generation can be offset by solar photovoltaic power generation. It can be used in grid interactive mode. The solar energy converter does not have moving parts and has a comparatively long lifetime. It is expected that such advantages would lead to further growth of solar photovoltaic power supply systems.

In order to achieve Government of India target of 100 GW Solar PV installations (including 40 GW rooftop solar PV installations) by 2022, quality standards and best practice recommendations are essential. It is also imperative to put in place an efficient and rigorous monitoring mechanism for adherence to quality standards and best practice recommendations.