EI Design

Table of Contents

Designing of EI and Fan Scheme

The aspects for the design are energy conservation, flexibility, aesthetics and user friendliness. Appreciation of these factors will help in a systematic approach. Besides these items of general nature there are certain specific requirements also of a particular building/space which need to be taken into consideration while finalizing the design. Giving regard to general and specific requirements certain recommendations are made for each type of building and for each of the spaces constituting the building. Recommendations are made towards the illumination levels, type of luminaries, controls and characteristics relevant to that particular space.

The scheme should prove to be of great use, however it is to be clearly understood that designing is a creative activity and these guidelines are to help and not to restrict one’s creativity. At the same time various aspects like energy conservation, flexibility, aesthetics, user friendliness are topics which brook no compromise and success in these areas have to be achieved in a good design.

  1. Energy Conservation: 

    The importance of this aspect needs no elaboration. In design we can contribute in this area by:

    1. Selection of lamps and fittings which are energy efficient.
    2. Designing for optimum level of illumination.
    3. Another aspect which can substantially contribute towards energy conservation is the concept of task lighting. It means that we divide our lighting schemes into (a) General Lighting and (b) Task Lighting. In order to provide the required level of illumination for a task we should not design the general lighting to that level. Level of general lighting can be kept lower say 100 - 150 lux and ensure higher level of illumination at the working surface provided by task lighting. This light will have individual control and can be switched on only when required thus further contributing to conservation of energy.
    4. Introduction of timers and other automatic controls to contribute in this area. For example in case of exhaust fans and particularly those provided in toilet areas which are one above other we can energize number of such exhaust fans (at various floors) from one circuit at ground floor. At this point we can provide timer so that these fans work only during the office hours and during this time also shall be switched on for half an hour and remain off for, let us say 15 minutes. This way we will be increasing the life of exhaust fans also without sacrificing the functional aspects and achieving conservation of energy as well.
    5. Automatic is rapidly gaining grounds in India. Use of ‘Day lighting’ and electronic chokes are areas not used today but may soon become viable. We should keep our eyes and ears open and introduce new features in our work as and when they have stabilized in our country.
  2. Flexibility: 

    Flexibility in our context means that the requirements which may crop up in future can be met by minimum amount of surface wiring. In case no thought is given to this aspect any future requirement has to be met by carrying out entire work in surface. For example at a later date we want to locate customer service center in entrance lobby and for this light, fan, AC is to be provided. It will call for surface wiring from the main board to this point. This surface wiring will run in important areas and obviously provided a shabby look. However, if, in the initial stage we had left say a 30 A TPN in the entrance lobby located at a point, not conspicuous, this later day demand can easily be met by minimal amount of surface work. This way the looks of the building will not be spoiled. Providing such power source in the beginning is a flexible design.

    Another example can be of the requirement of AC at a later date in a hall/cabins. In the beginning there is no AC requirement and hence no wiring is done. In such a case also if we had left a TPN of suitable capacity at some judicious location in the hall, the wiring to an individual AC can be carried out in surface at skirting level and we will not need surface wiring from the main board to the hall which would have run in common areas.

    Hence when electrical schemes are designed we should try to visualize needs which can crop up in future and take suitable steps to meet them at a later date with minimum damage to the looks of the building. For each building we have to stretch our imagination and make a provision which may prove to be handy in future. An intelligent and judicious approach is needed and it should be taken as a challenge. In nutshell, design should not cater to known requirements only.

  3. Aesthetics: 

    EI work designed by us should not only be technically sound but it should present a good appearance also. A person entering he building should be impressed by the way we have carried out our electrical work. The items which influence aesthetics of our work and hence of the building and can be addressed by us at the designing stage are:

    1. The location of Switch Control Boards: To highlight this point let us take the example of entrance lobby. If 2 / 3 switch boards are provided on the front and side walls and that also in the middle of walls, they will create a certain impression. On the other hand if these switch boards are located in a corner at places which are not conspicuous the walls readily visible will look clean. Our work will not spoil the aesthetics of the entrance hall. We have only located switch boards at places which are not readily visible, have not sacrificed any function but at the same time contributed towards good looks of the area. Hence location of switch boards should be carefully decided keeping this aspect in view. Without sacrificing functional aspects how best we can locate them is our challenge.

    2. Size of switch boards: Some times we are providing a single switch board from where large number of light and fans are controlled resulting in a size of 2 ft × 1 ft This big size becomes very conspicuous and does not add to the looks rather decreases the same. Our efforts should be to provide smaller size switch boards and in case more points are to be controlled we can resort to group control to reduce the number of switches. Small is not conspicuous, manageable and hence beautiful.

    3. Inter – relation of Switch Control Boards: Some times we have to provide switch board for light and fans, a switch board for light plug and a switch board for a power plug and may be for telephone out let also in close proximity. Result is number of switch boards of different sizes. If they are not properly interrelated we will find 4 sizes of switch plates at 2 / 3 levels on the wall and the impression will certainly be a bad one. Efforts should be made to locate them in such a manner that some sort of symmetry is achieved. If needed some controls can be shifted to different location to avoid an ugly situation. We should not see these controls in isolation but try to imagine as to how these will look when provided.

    4. Fixing arrangement of fittings: Down rods/chains, etc. are many a times used for fixing the fitting. Neither down rods nor chains provide good appearance. On the contrary many items such as junction boxes, finishing of ceiling outlets, covers, painting of down rods, levels etc. get introduced which call for quality control. If these fittings are mounted in flush with the ceiling our junction box etc. will get covered and installation will look neat. Hence we should resort to down rods and chains only when they are a must functionally. In corridors, entrance lobbies, toilets, staircases, etc. and most of the times the rooms also these can be avoided to enhance the aesthetic of our work. Our job will become simpler, economical and neat.

    5. Sizes of SDBs: Here also our efforts should be to ensure that our SDBs are of small size around 12” x 10”. Being small they will not look conspicuous. Larger boards generally do not integrate well with the surroundings. To achieve this, we have to limit circuits in a particular SDB say to six. In such a case our number of wires will also reduce which will facilitate maintenance. More number of wires means overcrowding in the SDBs. More number of small SDBs are recommended as a good design practice as well as for achieving aesthetic in our work.

    6. Risers (Main board riser / fire detection riser / telephone riser / wet riser.): Not only we should ensure (in architect drawings) that the risers are provided but also see that the spaces for above items are as per our needs, these should not be disproportionate to our requirements. Proper provision of risers improve quality of our work. In relation to risers one very important aspect which needs the attention from our end is that these areas should be suitably integrated with the building also. Drawing attached throws light on this aspect. It will be seen that main board, telephone riser & fire detector panel are provided with steel doors of normal size and are integrated in the building.These risers should be located away from the wet riser / sanitary shafts so as to avoid chances of water leakage in these shafts. Also suitable plug point should be provided in the rises for emergency light. If not properly planned these areas are finished in unplanned manner and are many a times result in eyesores. This being a very conspicuous item of our work must be given proper attention. Clear instructions should be recorded in drawings/item that front of he various risers should be finished in this manner so that site staff can get the same executed in the manner we have thought of.

  4. User Friendliness: 

    The location of lights, fans, their control points – light & power plugs are some areas where we can keep in mind the likely reaction of the user, and try to locate them in most user friendly manner.

    For kitchens, it is recommended that the control switch for light is provided at the entrance of the kitchen. In case it is provided inside the kitchen, initially it may be all right, but on account of storage racks provided at a later stage the switch may end up at a position not convenient. Somebody may decide to keep Fridge resulting in Control going behind it. Such situations can be avoided by keeping it out near the entrance. Light should also be provided on ceiling because, if on wall, storage racks at a later date may reduce its utility. Our efforts should be to make our installation convenient when used.

    Same thing holds good for fans and light control points in rooms. They should be available at the entrance so that one is not to travel in the darkness to reach them. Convenience in operation from bed should be kept in view. Light switch should be available at the entrance of the Quarters so that on entering you can switch on light without traveling in the dark. Plug points are another item which need due consideration. We should debate the use of the plug points and then only provide them at most convenient location. If provided in passage area they may not be useful at all.

  5. Integrated Approach: 

    Telephone wiring, Fire detection work, Air-conditioning, Power supply to computers through UPS, power distribution from substation to various loads should be properly visualized for integrated approach. All these services are likely to call for some adjustments in our EI and fans design and unless their requirements are visualized along with our EI schemes final product will no create overall good impression. Hence for a good EI and fans scheme we should have an integrated approach where requirements of other likely services are also taken into consideration.

Designing of Internal Electrification

Technical Buildings

The description of the type of lighting and level of illumination required is given:

  • Entrance Lobby: It should be designed in such a manner to create a good effect. Indirect lighting is ideal. Down rods should be avoided. Plug points, in case provided should be located at places not conspicuous.

    Illumination LevelLuminaireControl
    200 lux. (In case reception area is identified, the illumination may be increased by using task lighting (Table lamp/pendent lighting)In case of indirect lighting, ordinary box type fitting. For direct lighting mirror optic fitting with CFL lampControl should be at places not conspicuous, say in the corner near the entrance lobby.
  • Corridor: Sometimes corridors are used for return air boxing. In such cases wall mounting fitting on the wall just below the return air boxing are to be provided.

    Illumination LevelLuminaireControl
    100 luxCFL / single box fittingOn either side of the corridor. Group control if more number of lights.
  • Lift Lobby: In the main lobby, fan should also be provided. At other landings not necessary.

    Illumination LevelLuminaireControl
    200 lux in main lobby, 100 lux on other floorsCFL / mirror opticSingle control at non-prominent places.
  • Staircase: No fitting at mid landing as in most cases landing light should provide reasonable amount of illumination mid landing also and should be provided only in exceptional cases. If provided, it should be on wall at convenient height. At the same time it should be ensured that it is not a hindrance in the movement of material.

    Entrance lobby, corridor, lift lobby and staircase lighting may be divided in such a manner that for security lighting only a few lights can be switched on while the rest of them only when the areas are in general use.

    Illumination LevelLuminaireControl
    100 LuxCFL / mirror optic / box typeSingle control for entire staircase at ground floor.
  • Toilet: At least two lights may be provided on the ceiling. No light for the mirror should be provided unless its placing is certain. Exhaust fans should be provided if ventilation is poor. However they should be located in such a manner that short circuiting of air does not takes place. Fixing fans above windows should be avoided and location should be consulted with architect as generally it affects elevation. Fan opening in shafts should be avoided as many times shafts leak damaging the fans.

    Illumination LevelLuminaireControl
    100 luxCFL / single box typeOutside the toilet, near the entrance so that inside tile work is not affected.
  • External Area: For small and medium buildings, light can be fixed on terrace so as to illuminate the entire campus. However suitable pole lighting shall be provided where the campus is large.

    Illumination LevelLuminaireControl
     HPSV fitting for large area otherwise fluorescent fittingsPreferably in pump room for poles. If mounted on building, case to case basis decision. Photo switch recommended.
  • Engine Room: The fitting may be provided on the wall as it will be difficult to maintain the ceiling lights, once the engine is installed. A plug for the operation of fuel supply pump at the entrance may be provided. Also a plug for battery charger and other for emergency light may be given. Bracket fan can be provided near electrical control panel for maintenance personnel.

    Fresh air inlet opening of 1.5 times the size of radiator should normally be available by way of windows ventilators preferably at the back of engines for effective air movement. It should be discussed with architect. In case it is not possible, forced mechanical ventilation should be planned.

    Illumination LevelLuminaireControl
    200 luxSingle box typeNear the entrance.
  • HV Panel Room: Fitting may be provided on walls / ceiling. One fitting behind panel. A charging point for the batteries may also be provided.

    Illumination LevelLuminaireControl
    200 luxSingle box typeNear the entrance.
  • Transformer Room: Fittings should be provided on walls.ceilings. Exhaust fans should be provided at places where its effectiveness is ensured. A common timer may be provided for all the exhaust fans in the sub-station area so that they work on on-off cycle.

    Illumination LevelLuminaireControl
    200 luxSingle Box typeNear the entrance.
  • MV Panel Room: Fittings shall be provided on the wall / ceiling. The location of MV panel and bus duct should be kept in mind. Ceiling fan may also be provided. Exhaust fans should be provided at places where its effectiveness is ensured.

    Illumination LevelLuminaireControl
    200 luxSingle box typeNear the entrance.
  • AC Package Room: At least two lights may be provided for general illumination of the room while the location of other fittings should be decided so that they serve as a task lights for carrying out work in package units, power panel. In view of cable tray, refrigerant tray and ducting / plenum etc, fittings may be provided on the wall.

    Illumination LevelLuminaireControl
    200 luxSingle box typeAt the entrance for at least two lights for general illumination. Individual control for task lighting.
  • Pump Room: The fittings may be provided on the opposite walls.

    Illumination LevelLuminaireControl
    200 luxSingle Box typeNear the entrance.
  • Lift Machine Room: Fittings may be provided on the walls. Exhaust fans should be on walls opposite to air intake openings so that the proper flow of air is maintained. Their operation should be controlled with a timer so as to maintain on/off cycle. In case of machine rooms having more than two lifts, AC may be required accordingly suitable power point should be provided for the same. Plug points for pedestal fan should also be provided.

    Illumination LevelLuminaireControl
    200 luxSingle box typeNear the entrance.
  • Battery Room: Exhausts fans on outer walls should be provided with timer so that they automatically stops after about half an hour and should be switched on manually in case required. Slit / openings should be provided on the opposite wall / door for fresh air inlet. Lights should be mounted on the walls. Two plug points should be provided in the battery room.

    Illumination LevelLuminaireControl
    200 luxSingle box typeAt the entrance at least two lights for general lighting, other for task lighting.
  • Power Room: The lights for general purpose can be provided on the ceiling, other lights on wall. The exhaust fans should be provided on external walls and it should be ensured that on the opposite side suitable opening is available for fresh air entry preferably at lower level. The exhaust fans should be provided with timers for on/off operation. One plug point per bay should also be provided.

    Illumination LevelLuminaireControl
    200 luxSingle box type on wall, Mirror optic on ceilingAt the entrance at least two lights for general lighting, other for task lighting.
  • MDF Room: The general lighting may be provided for moving around in the MDF room at 100 lux. Task lighting should be provided in relation to racks. Each bay should have a single control. When task lighting is to be carried out at a later date, recessed wiring may be done to a recessed box near the probable location.

    Illumination LevelLuminaireControl
    100 lux for general lighting plus additional for task lightingTwin mirror optic for general and single mirror optic for task when mounted on ceiling otherwise single box, if mounted on wallFor general lighting at the entrance. Task lighting near the respective bays.
  • Transmission / PCM / Other Technical Room: Recommendation below are when detailed information is not available lighting is planned. If information is available designing should be done like that of a switch room.

    Illumination LevelLuminaireControl
    300 luxMirror opticNear the entrance and in group control to be judiciously decided to reduce the number of switches.
  • Switch Room: The lighting scheme is designed for general and task lighting. In case the equipment manufacturer provides luminaire along with the equipment no task lighting is required.

    Illumination LevelLuminaireControl
    100 lux for general lightingSingle mirror opticFor general lighting on ceiling at the entrance.
    150 lux for task lightingSingle mirror optic with a gap of 600 mm, which can be adjusted to get the 150 lux at floor levelTask lighting fittings are to be mounted in between the racks on a slotted channel to maintain a vertical clearance of 100 mm from the rack. Each row of lights shall have two controls, first 50 % of the lights by one switch, remaining by other switch.

Administrative Buildings

In an administrative building, the main problem is that the usage of the building is not decided when drawing is being finalized. However effort should be made to identify the following so that at a later date much patchwork is avoided:

  1. Conference / committee Room.
  2. Canteen.
  3. Inspection quarters.
  4. Space for locating air-cooled condensers, if even at a later date, Package AC units. This should be like a balcony.

The electrical design of the following areas should be like that of TE building as already described: entrance lobby, corridor, lift lobby, staircase, toilet block, external areas, engine room, MV, HV, and transformer room, AC package room, pump room, lift machine room and risers. The design of other areas should be as follows:

  • Cabins: Generally these are meant for very senior officers or for some specific purpose. In the case of officers cabin following should be taken care of:

    1. General lighting about 200 lux by twin mirror optic fitting with controls at the design.
    2. Provision for providing table lamp / pendant light to work as task lighting having control on the table.
    3. Provision of call bell from table.
    4. Provision of telephone wiring up to the table. Also interconnection with PA.
    5. Provision for computer installation.
    6. Provision for AC.

    In case cabin is provided for a specific use, electrical scheme may be designed accordingly.

  • Halls: These throws up the biggest challenges as partitions will come at a later date. Our planning based on hall concept will go astray and a lot of imagination is required. Following may be given attention so that difficulties may be avoided at a future date:

    1. Provide flexibility for later date power needs.
    2. Providing switching controls which can be proved beneficial at a later date.
    3. Include provisions for AC of larger areas with the help of PAC units.
    4. Include provision for power from UPS to computers at a later date.
    5. General lighting at 200 lux with the help of twin mirror optic fitting with control at the entrance.
  • Conference Hall / Committee Room: Normally these areas are provided with wall paneling and false ceiling as well as centralized AC. At the same time at the initial stage when we are doing our electrical planning these details are not finalized. In such cases it will be appropriate that we only provide some amount of lighting with fitting on the ceiling and provisions to carry out the wiring at a later date, according to the interior planning of the conference hall. These provisions can be left by way of suitable capacity power switches judiciously located in the Conference Room. From these switches, subsequent wiring can be carried out in surface (to be covered in paneling / cable trays) according to the interior planning of the room.

  • Canteens: Illumination level 200 lux with twin mirror optic fitting in group control. A change from normal office lighting can be provided by using bracket and pendant fittings. In addition to lights and fans there will be some power requirements for electric heaters and other electrical gadgets. In case the interior details of the canteen are decided, electrical points can be provided as per need, otherwise suitable TPN may be left at appropriate places.

Inspection Quarters:

  • Lobby: The lighting to be carried out with the help of decorative chandelier/wall brackets/pendant fittings. Also provision to be made for AC / TV. The lighting should look different from office areas.

  • Rooms: In the rooms a mix of mirror optic and wall brackets may be used. Special care should be taken to provide for night lamps, control of some lights and fans from bed and some from the entrance, provision for AC / TV.

  • Toilets: One light to be controlled form entrance. A light and socket to be provided near the mirror. Geyser should be controlled by DP switch with indication at convenient height and location. A connector may be left where geyser is expected. Plug socket should be provided. Exhaust fan, if provided should be properly integrated with the building and its location should be such that it is effective. Provision for cabin fan may also be made.

Training Centers:

  • Class Rooms: Here illumination level should be kept between 200 - 300 lux. Class room may consists of a black board or a raised platform for the lecturer. The control of light should be near the projector/lecturer, so that when using slide projector it can be switched off for better viewing. Based on these requirements illumination should be designed:

    1. Some lights on the wall above the blackboard to illuminate the same.
    2. At least two power plugs, suitably located so that slide projector can be energized which will normally be placed on the right hand side of the lecturer when facing the class. Efforts should be made that loose wiring which may be necessary for connecting the projector should not come in the way of lecturer moving on the raised platform.
    3. Control of light which can be operated by the lecturer at the time of slide projection. To reduce the number of switches, the lights in the class room can be group controlled.
    4. At least two lights preferably at the back of the class room which can be controlled from the entrance so that one can have some light in the room when entering in the dark. These lights can be twin controlled so that the same can be switched off from the control point.

Staff Quarters: 

  • Staircase / Entrance: Staircases should be considered as the extension of the compound lighting and single box type fitting may be provided. One switch may be provided at ground floor for lights provided on the main landings. No fitting at the mid landing are necessary as in most cases these are open to sky and some light will be there on account of room light.

    At the entrance one light point above entrance door with the control from inside should be provided.

  • Drawing Room: A mix of decorative brackets, pendant light and a box type fluorescent may be used to create a good effect.

  • Bed Room: One light control should be near the entrance while other can be located in such a manner that it can be operated form the bed. If the bed position is not decided, the location of board should be decided keeping in mind the future location of the bed. Twin control also may be thought of if it is more useful and is user friendly.

  • Kitchen: Here single box type fitting is recommended. Also power points should be provided for appliances. Its location should be away from sink. Exhaust fan should be provided keeping in mind its effectiveness.

  • Bath Room: Here control should be provided outside near the entrance. Light point should be on the wall for ease of replacement but it must be away from water. The connector in the junction box may be left at place where geyser is likely to come. However control should be with the help of DP with indicator conveniently located for operation.

    No socket need be provided in the bath room, however in case of wash basin with mirror, a suitable light on top of mirror along with plug point may be provided with control near the wash basin, but away from water.

  • Toilet: The light control should be outside at the entrance of the toilets.

  • Terrace: The use of terrace as a open area for social functions may be kept in mind for deciding lighting. Also a plug point and a spare TPN may be provided.

  • Balcony: The balcony should have a fitting fixed on wall as pendant fitting will swing on breeze. Also a plug point control at the entrance may be provided.

  • Plugs: The plug should be provided for the following: TV, radio, refrigerator, washing machine, desert cooler, mixer, grinder, shaver, computer, electric iron etc. While deciding the location of the plug following should be kept in mind:

    1. The type and location of appliance.
    2. Whether it will create any obstruction.
    3. Whether the point will go behind the bed.

    Depending on the type of quarter, a judicious guess may be made and suitable number of plugs should be provided at convenient locations. If it is exceeding the yardsticks, approval of CE should be obtained.

Some Important Points

  1. Fire bylaws and any statutory requirements will supersede these guidelines.
  2. The entire load of EI and Fans after applying diversity factor should be considered for working out the emergency load and Generator should be selected accordingly.
  3. In case size of the building demands a separate room for housing a common stabilizer / UPS, it should be demanded on each floor.
  4. Perspex fittings should be avoided in view of their poor efficiency.
  5. In case of blocked conduits, wiring should be carried out only for points which are very essential.
  6. In case of administrative buildings, a conduit may be laid with a junction box in each bay for future use. From this junction box wiring to a particular location may be carried out by recessing a channel in the floor.
  7. Following color schemes may be followed for differentiating between the junction boxes:

    Light & Fan:No colour.
    Power wiring:Yellow.
    UPS wiring:Blue.
    Fire Detection:Red.
  8. Use of self glow sign may be made.
  9. Too many junction boxes in the ceiling will spoil the look and they should not be allowed to be concentrated in one room. Suitable note for the same may be made in the drawing.
  10. Multipurpose light plug sockets to be provided in light and power circuits.


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