Design & electrical drawings

Without proper drawings and specifications, it becomes extremely difficult to undertake an electrical installation, if not impossible. In commercial and industrial projects where the electrical installation can be complex, drawings are in most cases provided by the architect. Unfortunately, in residential buildings, electrical drawings are sadly lacking. Home owners are urged to firstly employ an architectural professional to provide a full service and then make sure that an electrical drawing is compiled.

An electrical drawing doesn’t show the wiring, cable or conduit layout. It shows where each electrical point is situated within the building, and gives a brief description and a specification if necessary. An example of a simple electrical legend is shown in Figure 13.7. When compiling the electrical drawings, the architect and home owner will look into the functionality of the home and the home owner’s lifestyle and needs. See below for some design tips.

Other points that may not technically be electrical, or are installed by another contractor, can also be included on the electrical layout drawing. Some examples are:-

      • Telephone.
      • Computer connectivity.
      • Security systems.
      • TV connectivity, including satellite or aerial point.
      • Home automation.
      • Sound systems.
      • Intercom.
      • Electric gates.
      • Water storage tanks.
      • Swimming pool.
      • External lighting.
      • Airconditioning.
      • Photo Voltaic (solar) panel points and related connections.
      • Heat pumps.
      • Heating point.
      • Automated irrigation.
      • Boreholes.

Notwithstanding what has been mentioned already, here are some design tips:-

      • The height at which plugs (sockets) and switches are set may vary, but the norm is 1040mm above floor level for a light switch, 300mm for a plug (socket), and 1100mm for a plug (socket) above a working counter.
      • When placing plugs and lights, picture living and working in the proposed spaces of the building.
      • Go through the drawings room by room and take furniture into account. This applies to lighting and plugs.
      • If home automation systems are going to be installed, it is wise to design the installation with a consultant.
      • In the kitchen area, work closely with the kitchen manufacturer/installer. Plug points are inexpensive as a percentage of the building cost. Rather have two or three too many than be short. Extension cables across a kitchen counter never look good. Properly position lights and correct light fittings are critical in a kitchen. Again, kitchen units and accessories must be taken into account. The position of the stove is important because of the stove isolator. Moving the stove isolator point after building can be costly. Other fittings like extractor fans must be considered.
      • The electrical points in a bedroom need to be considered with the furnishing in mind. Television, data, ceiling fans, air conditioning and telephone points may also be required. Remember home automation.
      • Lighting in bathrooms is important, but one must remember that only light fittings made for bathrooms can be fitted. Regular plugs (sockets) may not be fitted in a bathroom. A purpose made shaver point may be fitted. The switch for the lights must be installed outside the bathroom. If required, heated towel rail points may be positioned.
      • In living areas and lounges, electronic equipment becomes important. Connectivity for televisions, decoders, high-fi, speakers and so on needs to be considered. Modern wireless systems that connect electronic equipment together makes an installation easier, but it still needs to be thought through.
      • Dimmer switches for lighting may also be required in living areas. 2-way switching where a light can be turned off and on from two different points may also be required in large living areas.
      • Lighting in passages and on staircases need to be adequate and safety must be taken into account. 2-way switching is almost always required in these areas.
      • As the distribution board is not aesthetically pleasing,it is usually positioned in the garage. The home automation system will usually be positioned in the same area as the distribution board.

Information supplied by Buildaid Publishing.

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