A reflected ceiling plan (RCP) is a drawing of a room or space looking down at the interior ceiling. The designer or architect produces this plan to graphically show the ceiling treatment, ceiling grid, and the placement of all light fixtures as well as light fixtures to be relocated or removed. The plan indicates the type of ceiling (acoustical tile, gypsum board, etc) and the ceiling heights. The location of all light fixtures, speakers, special lighting, ceiling outlets, and switch locations is indicated and labeled. A ceiling-fixture legend is also normally included to provide a description for each symbol.
The engineer creates the electrical drawing for the RCP. It is an engineering drawing separate from the architectural set. The engineer prepares his/her own drawings based on floor and reflected ceiling plans provided by the interior designer or architect. The plans indicate to the engineer the location of light fixtures, special ceiling features, toilet rooms, and any equipment requiring special venting.
The engineer's drawing shows the circuiting and switching for each item on the ceiling. The circuit connection to the panel is labeled. Conduit size when required, legends, and general and/ or specific notes are provided on this drawing.
The RCP is basically a view of the ceiling from above. It is as if you were floating above the ceiling and looking down at it (Figure 6.22). This view will show the location of light fixtures, drywall or T-bar ceiling patterns, and any items that may be suspended from the ceiling. Figure 6.22 also shows a lighting layout plan.
Many projects will require electrical and mechanical drawings. The interior designer or architect will provide the electrical and/or mechanical engineer with their reflected-ceiling-plan design. The engineer will add the required information.
A reflected ceiling plan is drawn to scale. This means that the plan is measured proportionally to a size that will fit on a drawing sheet. A reflected ceiling plan will most often be at the same scale as the floor plan. A common scale is one-quarter inch = one foot (scale: 1/4 inch = 1 foot, 0 inches). The reflected ceiling plan will be titled with the scale noted at the bottom.
In a reflected ceiling plan each light fixture has an identification letter. A light-fixture legend is included on the actual drawing sheet. In the legend, each fixture is listed with its letter and a specification. The numbers in the hexagon shape are key notes. They describe items on the reflected ceiling plan. For example: number 2 would list the specification for the T-bar ceiling. Ceiling heights are noted in the oval shape.
The engineer's drawings must specify the type, location, and number of panels. On large or complex projects a circuit-breaker layout is included. This can take the form of a legend or diagram which typically includes number of panels and ampere loads.
The engineer must provide a load summary of the total connected load (amps/watts) for all items shown on the power and RCP drawings. This ensures that the main service is adequate. Many cities and towns have energy-conservation regulations regarding electrical loads. The engineer's drawings must abide by all codes and bylaws pertaining to the city, town, or province where the project is located.
The following are typically included in a set of electrical drawings:
• Type and location of outlet, (duplex, dedicated, isolated ground, GFI, etc.)
• Size and type of conduits (data, communication, phone)
• Volts of switches, wiring, and circuitry
• Lamps and model numbers of light fixtures
Other information may be needed, depending on the complexity of the project:
Direct connections (junction boxes, etc.) Emergency lighting and exit signs Alarm and security systems Fire-alarm systems
Sound systems, speakers, monitors, and cameras Special equipment (kitchen, entertainment) Special technical devices (computers, gauges, medical, etc.) Special wiring (signs, heating, saws)
LIGHTING LAYOUT scale: vs- = r-o" Figure 6.22B Lighting layout plan drawn to a scale of 1/8 inch = 1 foot, 0 inches.
Engineer's drawings are required for all commercial projects involving electrical work, including additions, renovations, and new construction. A permit is required prior to commencing any on-site work. Drawings and permits are also needed for residential projects when substantial electrical work is to take place. For small projects, a licensed electrician can provide the information required to obtain an electrical permit.
Concept and designs are the first stage of any project. When established, the next stage is construction drawings. Once the floor and reflected ceiling plans are complete, they are passed to the engineer to produce the electrical drawings. The engineer's drawings become part of the construction-drawing set.
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