Electrical equipment and installations

Electrical power is one of the most important inputs for a chemical industry. Requirement of power, type of installations for drawing power from external grid, using it safely and eflhcientiy in the process units and machinery should be looked into carefully by the plant engineers as well as senior management. 

High Tension Supply from External Grid 

Transfotmea for Furnace beating Three/Single phase 

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Some unsafe electric equipment and installations can be identified by the presence of ... 

The periodic inspection and testing by a competent person of electrical equipment and installations as a statutory requirement arises explicitly only under the Cinematograph (Safety) Regulations 1955 which require inspection and testing by a competent person every 12 months. 

Electrical Classification. In those areas of the plant where a hazardous quantity of dust accumulates or is suspended in the air, the area should be classified and all electrical equipment and installations in those areas should comply with Article 502 or Article 503 of NFPA 70, the National Electrical Code,... 

In most laboratories and workshops where highly flammable liquids or combustible gases are used there is a strong prohahihty that a vapour-air mixture within the flammable limits will persist for some period of time. Whether a fire results will depend upon whether this transient flammable mixture contacts an ignition source. All workplaces contain a variety of potential ignition sources, ranging from the obvious open flames, electrical equipment and installations, and heating apphances which are necessary for the work activities, to the surreptitious smoker who is a hazard to the work activities. 

General principles for temperature limits in the rating of electric equipment and for the evaluation of electrical installation... 

All other applicable rules contained in this Code shall apply to electrical equipment and wiring installed in hazardous (classified) locations. 

Laboratories working frequently with flammables, such as in extraction processes, may set aside a separate room for such work for maximum safety. Ideally, this room should have explosion-proof electrical equipment and special ventilation. Rigid work rules should be enforced, such as requiring workers to leave matches and lighters on a shelf outside before entering. Installation of conductive flooring should be considered, and steel tools should be prohibited at times when work is in progress. 

When designing an XP area, all pieces of electrical equipment and instrumentation are specified for the class, group, and division, as discussed previously. All pieces of equipment and instrumentation within an area must be appropriately specified and installed. The overall classification is only as good as the piece of equipment in an area with the lowest classification. 

All electrical equipment and wiring installed in hydrogen gas transmission and distribution compressor stations shall conform to the requirements of NFPA 70, insofar as the equipment commercially available permits. Electrical installations located in hazardous areas, as defined in NFPA 70, and that are to remain in operation during compressor station emergency shutdown, as provided in para. I-1.3.2.1(a), shall be designed to conform to NFPA 70 for Class I, Division 1 requirements. 1-1.3 Compressor Station Equipment... 

Electrical Arcing and sparking from electrical equipment, including industrial trucks Install appropriate electrical equipment and appropriate industrial trucks NFPA 70 NFPA 505... 

QUALIFICATION Qualification is a documented program which provides the assurance that the equipment and installations operate consistently within the predetermined mechanical, electrical or other operating parameters. 

Electrical work Work on electrical equipment and on low and high voltage systems with the hazard of a dangerous electric shock Access to electrical installations... 

Underground station An enlargement of an entry, drift, or level at a shaft at which cages stop to receive and discharge cars, personnel, and material. An underground station is any location where stationary electrical equipment is installed. This includes pump rooms, compressor rooms, hoist rooms, battery-charging rooms. 

Part 5 of the lET Regulations tells us that electrical equipment and materials must be chosen so that they are suitable for the installed conditions, taking into account temperature, the presence of water, comosion, mechanical damage, vibration or exposure to solar radiation. Therefore, PVC insulated and sheathed cables are suitable for domestic installations but, for a cable requiring mechanical protection and suitable for burying underground, a PVC/ SWA cable would be preferable. These two types of cable are shown in Figs 3.38 and 3.39. 

Electricity supply authorities discourage the use of equipment and installations with a low power factor because they absorb part of the capacity of the generating plant and the distribution network to no useful effect. They, therefore, penalize industrial consumers with a bad power factor through a maximum demand tariff, metered at the consumer s intake position. If the power factor falls below a datum level of between 0.85 and 0.9 then extra charges are incurred. In this way industrial consumers are encouraged to improve their power factor. 

Before beginning this final chapter on electrical installation wiring systems, the City and Guilds syllabus tells us to revise some of the work done in previous units because they are relevant to installing electrical equipment and systems in buildings. I will tell you where to find the appropriate revision material in this book. 

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