In an electrical installation project, quantity and type of power outlets is one of the critical factors. This factor depends on the building and on the equipment used therein. This information is usually given by the client. With this information, and based on the Brazilian standard NBR 5410 from ABNT, which determines the minimum requirements for quantity and type of power outlets, we can design the requirements for the electrical installation (conduit, cables, protection, etc.) to supply the power outlets in the building.
In this post, I will talk about the quantity of power outlets required by the Brazilian standard NBR 5410:2008 for housing locations (section 9.5.2.2 in NBR 5410:2008). This post aims to be informational and the content discussed herein must be understood as information material only. We recommend that a professional engineer be consulted and that the current version of the Brazilian standard NBR 5410 be used during the design and building of the project.
In the NBR 5410 standard, housing locations are defined as rooms that people can use to inhabit, either fixed or temporarily. Examples of housing locations include houses and hotel rooms. In these locations, the quantity of power outlets (a power outlet can have one or more power outlet inputs; the image on the side shows a power outlet with two inputs) depends on the function of the room and the equipment used therein:
- Bathrooms: at least on power outlet. This power outlet must preferable be located near a washbasin, where people might want to use hair driers, electric shavers, etc. One of the challenges in design a power outlet in bathrooms is the fact that people might be wet, which increases the risk of electrical shocks. To reduce the risk of electrical shocks, the designer must follow the instructions in the section 9.1 (which we will discuss in another blog post).
- Kitchen, service areas, and similar: one power outlet for each 3.5 m or fraction of the perimeter of the room; near the washbasin, two power outlet inputs (which can be located in the same power outlet). In these locations, people usually use several different appliances (for example, blender, toaster, microwave, and electric oven), which justifies the higher quantity of power outlets.
- Porch: at least one power outlet. In two specific cases, this power outlet can be installed in another place near the porch. One of the cases is when the porch is small (area less than 2 m2 or length less than 0.80 m). The second is when, for technical reasons, a power outlet in the porch is not possible to be built and installed.
- Living rooms: one power outlet for each 5 m or fraction of perimeter of the room. In addition to the minimum requirements, designers must think about the quantity of appliances that might be connected near each outer. For example, in the same power outlet, a person might connect a TV, a receptor, and a mobile phone charger. This is one of the cases where the designer might consider using a power outlet with multiple inputs.
- Bedrooms: one power outlet for each 5 m or fraction of perimeter of the room. Similar to living rooms, designers should think about the possibility of a person using several home appliances connected in the same power outlet.
- Other rooms (for example, home offices and storage rooms): The quantity of power outlets in these rooms depend on their size. For small rooms (area up to 2.25 m2), the power outlet might be installed outside the room but near (up to 0.80 m) from the room access door. For medium sized rooms (areas greater than 2.25 m2 and up to 6 m2), at least one power outlet must be installed inside the room. For bigger rooms (area greater than 6 m2), designers should follow the recommendation for living rooms and bedrooms (one power outlet each 5 m or fraction of perimeter).
Example 1. Bedroom with 4 m x 5 m.
The perimeter of the room is calculated as 2 x 4 m + 2 x 5 m = 18 m. Hence, the minimum quantity of power outlets is equal to 18/5 => 3.6 => 4 power outlets.
Example 2. Home office with 2 m x 3 m.
The area of the home office is 2 m x 3 m = 6 m2. Hence, we need at least one power outlet inside the home office.