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Home / Technical Articles / Electrical Design Project of a Three Bed Room House (1)

Requirements and Standards

Electrical design is not an easy task. It requires a lot of expertise. Detailed study is needed prior to installation work. The engineer must consider quality and any specific requirements together with price. Different options are to be examined.

Electrical design project of a three bed room house (Part 1)
Electrical design project of a three bed room house (Part 1)

Choice of room utilization, decor, hobbies and the activities of the various residents are now critical to electrical design.

Electrical installation cannot make universal provision for every conceivable arrangement.

Customer is the key person in determining the final arrangement. BS 7671 (the Wiring Regulations) will often recommends that a project should be discussed with the client.

Flexible design approach is now often practiced. Standards for the house industry are determined by the National House Building Council (NHBC).

The minimum requirements

The following is an outline of basic requirements for a three-bedroom house with 120m2 floor area. This would be a typical speculative estate development (Figure 2).

  1. Rooms: small kitchen; dining room; lounge; downstairs cloakroom; main bedroom with en-suite bathroom; second double bedroom; small single bedroom; landing bathroom or shower room;
  2. Heating: central heating by gas or oil;
  3. Garden: small garden at both front and rear.
Bathroom zones
Figure 1 – Bathroom zones


National House Building Council (NHBC)

The NHBC give minimum standards for living accommodation and services, which are shown in Table 1. It should be noted that houses vary in size and use, so the values given should be considered as a minimum.

Table 1 – NHBC recommendations for a house.

13 A socket-outlets (twin socket count as two outlets)

Kitchen/Utility 6Where homes have separate areas, the kitchen should have a minimum of four outlets and the utility room two.
Utility 3Where appliances are provided, at least three outlets should be for general use.
Dining room 3
Living room 4At one double outlet family room should be near the TV aerial outlet
Bedroom 3 (2)Three for main bedroom. Two for other bedrooms
Landing 1
Hall 1
Combined rooms should have sockets equal to the sum of the number for individual rooms, with a minimum of seven in the case of kitchen / utility and another room.
Every room should have at least one lighting point. Two-way switching should be provided to staircases.
Smoke detectors
For this two-story house, two mains operated, interconnected alarms are required.

Relevant wiring regulations 13 A socket-outlets

  1. Building Regulations now require socket-outlets, wall switches and other similar accessories to be sited in habitable rooms at appropriate heights of between 450 and 1200mm from the finished floor levels.
  2. Any socket-outlet with a rated current not exceeding 20 A, which is used by ordinary persons’ equipment for outdoors use must be provided with additional protection by means of a 30mA RCD.
  3. No 230V sockets, except shaver sockets complying with BS EN 61558-2 are permissible in bathrooms and shower rooms.
  4. 230V socket-outlets must be located at least 3m outside the boundary of zone 1 and provided with 30mA RCD protection.


  1. To avoid danger and inconvenience, there should be more than one lighting circuit.
  2. In a bathroom, all equipment must be suitable for the zone in which it is installed.
  3. Wall switches and other accessories must not be installed in zones 0, 1 and 2.
  4. Cord switches must be installed outside of zones 0, 1 and 2, but the cord may hang within zones 1 and 2.
  5. There are restrictions on the current-using equipment in zones 0, 1 and 2.
  6. Equipment that is installed in zones 1 and 2 must have water penetration protection of at least IPX4.
  7. A careful study of BS 7671: (Most recent version) Section 701 is recommended.
Figure 2 - Typical three bedroom house
Figure 2 – Typical three bedroom house

Will be continued soon…

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More Information

Sufi Shah Hamid Jalali

B.Sc. in Electrical Engineering. Designer of websites. Currently working as Electrical Engineer at Aga Khan Foundation, Afghanistan. Likes to write and share knowledge of Electrical Engineering. Knows Primavera P6, Graphics, Professional AutoCAD and Project Management.


  1. Salami oladele
    Sep 15, 2021

    I like your gives me more updates about electrical.i like to know how to calculate load and installation height .thanks

  2. Felix fiebor
    Aug 23, 2021

    What is the easiest and practical way to estimate quantity of lighting and socket cables for a normal bedroom

  3. Ubon Ukpong
    Jun 09, 2021

    Please, I really want to know the size of cable one can use to earth a building of 3 bedroom flat?

  4. Prosper piere
    Nov 24, 2020

    Please sir, can you help me load ratings of 3 bedroom flat and the cable sizes to be use, thank you.

  5. kc-ann bagtang
    Sep 28, 2020


    you are going to design an electrical layout of 3 bedrooms residential house with the following contents:
    1. INTRODUCTION – discuss all about your design.
    2. DEFINITION OF TERMS – discuss the terms you use in your design ex. circuit define it.
    10. COMPUTATION – computation on how you got the values you put in the schedule of

    can some one give an answer for this?????THANKYOU SO MUCH!

    • Virginia Gonzalez
      Nov 24, 2020

      Good afternoon,

      There is a guide for the calculation of electrical installations for premises (supermarkets)

      • fe ner
        May 27, 2021

        Please, could you send me a format on how to calculate the load of a three-bedroom flat?

  6. Ekemini I
    Jun 24, 2020

    I won’t to be able run the writing

  7. Uchenna Ndukuba
    Jun 08, 2020

    Pls can u send me a format on how to calculate load of three bed room

    • bony dutta
      Jun 26, 2020

      there is a method that you can do it easily if you want to learn it just email me:[email protected],i m a electrical designer, i can explain you properly

      • Bello A Emmanuel
        Jul 23, 2020

        Hello can u send me d diagram of how to install bed switch and socket in room and sitting room. Thanks for ur concern.

      • Elisius
        Oct 04, 2020

        Please, could you send me a format on how to calculate load of a three bedroom flat.

      • Paul oguguo
        Feb 18, 2021

        Pls sir I need more explanation

  8. Mohammad Ehsan Ullah
    Jan 16, 2020

    I am teacher and I hope that learn more thing from you.

  9. Yogesh Khetani
    Nov 25, 2019

    Couldn’t understand a thing here.

  10. JEFF
    Aug 01, 2019

    well explained but i would want to know the height of sockets installled in normal rooms and those ones in pantry, kitchen and utility rooms.where do we install weatherproof sockets and why.

  11. Ezekiel esin
    Jun 23, 2019

    I want to acquire more skills also know the machine that is use for load balancing

  12. lucasamelia
    Jun 21, 2019

    Really helpful post about electric design for a three bedroom house, Electricity is also a basic need of every person so there should be facilities of electricity. Keep giving updates.

  13. Abdulmajeed
    May 09, 2019

    Thank you very much… This really helps

  14. Elijah
    Jan 17, 2019

    Like your post. Pls kind I have electrical diagrams and materials for a 5-Bedroom duplex; GF- large living room/dinning, kitchen, 2 rooms and foyer. FF: 3 rooms, 2 study room, small private living room and balcony. Thanks.

    • Vidhu Krishnan
      Jan 19, 2019

      We deal in all Electrical and AC works as per the customer needs.We have a good team to work at 24×7 maintenance of Electrical,plumbing and AC installation.We have completed more than 200 plus villas and commercial units from the last one year.Let us meet and discuss the or msg 66337791

  15. kailash khanduri
    Dec 27, 2018

    how many twin control light point in a 3 BHK residential flat ?

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