Electrical Layout Planning for New Homes

Most electrical problems in Indian homes are planning problems that show up years later. An extension board snakes from behind the sofa because the TV wall had one socket. The bedside lamp is plugged in under the bed. The geyser and the washing machine share a circuit and the MCB trips every winter morning. The air-conditioner in the third bedroom runs from a 6 A socket through an adaptor because nobody thought that room would get one. None of these is a wiring fault in the narrow sense; each is a decision that was never taken, or was taken by the site electrician on the day the walls were chased.

New homes — a bungalow being built, a flat taken bare-shell from a builder, or an apartment being fully re-done — are the one moment when electrical work is cheap. Before plaster, a new point is a length of conduit, a box and some wire. After tiling, the same point means breaking a finished wall, patching, repainting and living with a mismatch. That asymmetry is why an electrical layout drawing deserves as much attention as the kitchen or the wardrobes. It is the least visible drawing in a home and the most expensive one to get wrong.

This article is a planning guide for homeowners and designers. It explains the codes that govern wiring in India, how to estimate load and divide a home into circuits, what goes into the distribution board, how many points each room needs and at what heights, how cables and conduits should be routed, and what all of it costs. It is not a substitute for a licensed electrician: the design of protective devices, cable sizes and earthing must be done and certified by a qualified, licensed electrical contractor working to the codes. What a homeowner and a designer can do — and should do — is give that electrician a clear, complete brief.

Safety first: the codes and who is responsible

Electrical work in an Indian home is governed by a small family of documents. IS 732, published by the Bureau of Indian Standards, is the code of practice for electrical wiring installations: it covers how circuits are arranged, how cables are selected and protected, how installations are earthed, inspected and tested. The National Electrical Code of India, also published by BIS, gathers the wider body of electrical practice for different building types into one reference. The National Building Code of India 2016, Part 8 (Building Services), Section 2, deals with electrical and allied installations in buildings and points back to these standards. Supporting standards cover the components themselves — earthing practice (IS 3043), PVC-insulated cables (IS 694), conduits (IS 9537), and the miniature circuit-breakers and residual current devices that sit in the distribution board. On top of these sit the Central Electricity Authority's safety regulations and the rules of the local electricity distribution company, which inspects the service connection and meter.

The practical message for a homeowner is simple. Wiring must be designed and carried out by a licensed electrical contractor, under a supervisor holding the competency certificate that the state licensing board issues, and the contractor should test the installation and hand over the results. A designer or architect decides where points go and what they serve; the electrician decides — and is accountable for — cable sizes, protective devices, earthing and the connection to supply. When these two roles are blurred, the usual result is a beautiful layout on undersized wires, or correct wiring in all the wrong places.

How house wiring got here

Many Indian homes still carry the history of house wiring in their walls. Older buildings often had surface wiring run on wooden battens or in wooden casing-and-capping, with porcelain rewireable fuses — the familiar kit-kat fuse — in a fuse box near the meter. Aluminium conductors were common in older installations. Switches were heavy, round or piano-key types screwed to wooden boards. These systems worked for a few lights, a fan and a radio; they were never meant for air-conditioners, geysers, induction hobs and a dozen chargers.

Over the following decades, concealed wiring in PVC conduit chased into walls became the norm in new construction, copper replaced aluminium for internal wiring, and the miniature circuit-breaker replaced the rewireable fuse. Earth-leakage protection arrived first as voltage-operated ELCBs and then as current-operated residual current circuit-breakers (RCCBs), which are what homes use today. Modular switch plates, flame-retardant cables and pre-wired distribution boards followed. Each change made homes safer; none of them removes the need for a plan. A modern home simply has more of everything — more loads, more points, more circuits — so the plan matters more than it did.

Step one: estimate the load before drawing a single point

Every electrical design begins with the appliance list. The load a home draws decides the supply the electricity board must sanction, the size of the incoming cable and main switch, whether a single-phase connection is enough, and how the circuits should be split. The list should include not just what the family owns today but what it will reasonably own in the next ten years: an air-conditioner in every bedroom, a second geyser, an induction hob or built-in oven, a dishwasher, and — increasingly — an electric vehicle charger in the parking.

Adding the rated loads gives the connected load. A home never runs everything at once, so electricians apply diversity — the realistic share of the connected load that runs together — when sizing the main cable and the sanctioned load. A typical modern 3BHK with four air-conditioners, two geysers and a full kitchen easily reaches a connected load of 12–18 kW, while the realistic simultaneous demand on a summer evening may be 6–9 kW. Distribution companies in different states set their own thresholds for when a connection must be three-phase; many larger flats and almost all bungalows with several air-conditioners are better served by a three-phase supply, with the loads balanced across the three phases. The exact rule should be confirmed with the local DISCOM before the meter application is made.

Step two: divide the home into circuits

A circuit is a group of points fed by one cable from one protective device in the distribution board. Good circuiting has three aims: no circuit should be overloaded, a fault on one circuit should not darken or disconnect the whole home, and heavy appliances should not share cables with light loads. The simplest rule that achieves this is to keep lighting, general sockets, kitchen power, air-conditioners and water heaters on separate circuits, and to split each of these between the living side and the bedroom side of the home.

The table describes common practice in Indian homes, not a design: actual cable sizes depend on the load, the length of the run, how many cables share a conduit and the installation method, and they must be selected by the electrician to IS 732. Two further habits are worth insisting on. First, every circuit should carry its own neutral back to the board, so that each RCCB group sees only its own current — shared neutrals across RCCB groups are a common cause of unexplained trips. Second, the distribution board should be labelled circuit by circuit, and a copy of the circuit schedule should stay with the homeowner.

MCB, RCCB and earth: what each one actually does

The three protections in a home do three different jobs and none replaces another. The miniature circuit-breaker (MCB) protects the cable: it trips when the current exceeds what the cable can carry safely, as in an overload or a short circuit. B-curve MCBs suit lighting and resistive loads; C-curve MCBs tolerate the starting current of motors and compressors and are commonly used for air-conditioners and pumps. The residual current circuit-breaker (RCCB) protects people: it compares the current going out on the phase with the current returning on the neutral, and trips when some of it leaks to earth — through damaged insulation, a wet appliance or a person. For protection against electric shock, a sensitivity of 30 mA is the standard choice in homes. Some installations add a less sensitive RCCB, such as 100 mA or 300 mA, at the incomer for protection against fire from leakage. The earth gives fault current a safe path so that protective devices operate, and keeps exposed metal parts — appliance bodies, metal boxes — from rising to a dangerous voltage. An earth pit that is never tested, or an earth wire left unconnected at a socket, quietly removes this protection.

Step three: plan points room by room

Points should be drawn on the furniture layout, never on an empty plan. A socket only makes sense once the bed, the sofa, the study table and the kitchen counter are drawn, because its job is to be next to something. The most reliable method is to walk through a day in the home: where the family charges phones at night, where the iron is used, where the router sits, where the vacuum cleaner is plugged in, where the festival lights go on the balcony. Each of these is a point. The table gives a starting count for a 3BHK of about 1,200–1,300 sq ft carpet area, consistent with the room sizes and lighting plan used across Aaditya Interior's design notes.

Added up, this gives roughly 100–140 points for a typical 3BHK, which is a useful check against a builder's specification sheet: many builder-standard flats are delivered with far fewer, which is why so many new homes need electrical additions before the interiors begin. Two rooms deserve special care. The kitchen has the highest density of heavy appliances in the home and should be planned with the cabinet drawings in hand, so that sockets land inside the right units. The bathrooms combine water and electricity: sockets and switches must stay well away from the shower and bath area, geyser switches are best placed outside the bathroom or at a high level outside the splash zone, and every bathroom circuit should be behind 30 mA RCCB protection.

Heights: switch boards, sockets and appliance points

Mounting heights are the part of the electrical drawing that homeowners notice every day. They should be written on the drawing as heights above finished floor level (AFF), not left to the electrician's habit, because the floor finish, skirting and furniture all change what is comfortable. The heights below are the ones used in Aaditya Interior's lighting and room-planning articles; they are typical Indian practice rather than code values, and a project can vary them for a reason — a lower door switch for a wheelchair user, for example, or a higher socket where a child must not reach.

Step four: route conduits so the walls stay safe

Concealed wiring is laid in PVC conduit chased into masonry or embedded in the slab before concrete is poured. The quality of this hidden work decides how safe and serviceable the home will be for the next twenty-five years. Three principles cover most of it. Conduits should run vertically or horizontally from a point, never diagonally across a wall, so that anyone drilling later can predict where cables are. Conduits should be continuous from box to box, with proper bends rather than kinks and with draw wires, so that a damaged cable can be pulled out and replaced without breaking the wall. And separate conduits should be used for power, lighting, data and television, both to avoid interference and to keep circuits independent.

Slab conduits for ceiling lights and fans should be laid with the structural engineer's knowledge, should not be bunched over beams or columns, and should be checked before the concrete is poured — a crushed or disconnected slab conduit is one of the most frustrating faults to trace later. Wall chases should be cut with a machine, not hacked with a chisel, and should be shallow and narrow enough not to weaken thin walls; deep horizontal chases in load-bearing or thin block walls should be discussed with the engineer. Before plaster closes the chases, every wall should be photographed with a tape measure in the frame. Those photographs are worth more than any as-built drawing when a picture or a TV bracket has to be fixed years later.

Cables, boxes and switches: what to specify

For internal wiring, copper conductors with flame-retardant (FR) PVC insulation are the common standard in Indian homes, and FR-LS (low smoke) or halogen-free cables are a sensible upgrade in escape routes, staircases and larger bungalows. Each circuit needs a phase, a neutral and an earth conductor, identified by distinct colours as the code specifies — red or brown for phase, black or blue for neutral and green or green-and-yellow for earth are the colours most often seen. Cables should be bought from the manufacturer's sealed coils and checked for BIS marking; unbranded wire sold by length on site is the most common false economy in home electrical work.

Boxes should be metal or good-quality PVC modular boxes sized for the plate, deep enough to take the wires without cramming, and set flush with the finished plaster — a box set too deep leaves a plate rocking on long screws, and one set proud stops the plate sitting flat. Switches and sockets are chosen for range and finish, but three functional choices matter more than the look: shuttered sockets in homes with children, combined 6/16 A sockets where an appliance might move, and USB charging modules at bedsides and desks to retire the tangle of adaptors. Deep boxes and a neutral wire at every switch position are worth asking for even if no smart switches are planned, because most smart switches need both.

What electrical work costs in 2026

Electrical work is priced in India either per point or as a lump sum built up from points, materials and the distribution board. Per-point rates hide large differences — a light point six metres from the board in an existing conduit is a very different job from a new 16 A point chased into a finished wall — so the quotation should state what each point includes: conduit length allowance, cable size, box, switch or socket and plate range. The figures below are indicative October 2026 ranges for new concealed wiring in a flat or bungalow, with mid-range branded materials; they vary with city, copper prices and brand, and should be confirmed locally.

These numbers sit alongside, not inside, the lighting budget: the light fittings, coves and drivers for a typical 3BHK are a separate ₹45,000–1,65,000 at indicative October 2026 rates. The cheapest place to save money is the switch-plate range, which can be upgraded later in an afternoon. The worst places to save are cable quality, earthing and protective devices, which cannot be upgraded without opening walls and which are the parts that keep people safe.

Where home electrical design is going

Three changes are already reaching ordinary Indian homes. The first is load growth: air-conditioning in every bedroom, induction cooking and electric water heating have pushed connected loads up, and the electric vehicle is the next large load. A home designed today should have a spare conduit from the distribution board to the parking and a board with spare ways, even if the charger comes years later. The second is solar: rooftop systems with net metering are now common on bungalows and are appearing on low-rise apartment terraces, and they need a planned route from the roof to the inverter and the board, a location for the inverter itself, and coordination with the DISCOM. The third is control: smart switches, scene controllers and sensors are becoming standard in mid-range homes. All three are far easier if the wiring anticipates them — neutral at every switch box, deep boxes, separate data conduits and a few empty conduits to likely future locations.

Battery backup is changing too. The familiar inverter with lead-acid batteries in a cupboard under the stairs is giving way to lithium-ion units and to hybrid solar inverters, and the question is no longer only where the battery sits but which circuits it should carry. Planning this on the drawing — marking which lights, fans, sockets and the router will run on backup, and wiring them as a separate group in the board — is a small decision at layout stage and an expensive rewiring job later.

Rules for approving an electrical layout

• Draw every point on the furniture layout with its height above finished floor; reject any electrical drawing made on an empty plan.
• List every heavy appliance — each AC, geyser, oven, induction hob, pump and a future EV charger — and give each its own circuit.
• Split lights, 6 A sockets, 16 A power, ACs and geysers onto separate circuits, and split the home between at least two 30 mA RCCB groups.
• Ask the licensed electrician to confirm cable sizes and MCB ratings in writing against IS 732, and to label the board circuit by circuit.
• Insist on a tested earth: earth pits recorded, earth continuity checked to every socket, and the test results handed over.
• Run conduits only vertically and horizontally from boxes, use separate conduits for power, data and TV, and leave draw wires in every run.
• Provide a neutral and a deep box at every switch position, plus spare conduits to the parking, the terrace and the TV wall.
• Keep 20–30 per cent spare ways in the distribution board for future circuits.
• Photograph every chased wall with a tape in frame before plaster, and keep the photographs with the as-built drawing.
• Never accept a socket fed from a light circuit, a shared neutral between RCCB groups, or an MCB upsized to stop it tripping.

Frequently asked questions

How many electrical points are needed in a 3BHK flat?

A comfortable 3BHK of about 1,200–1,300 sq ft carpet area typically needs 100–140 points in total, counting light and fan points, sockets, dedicated appliance points, and data and TV outlets. The kitchen and the master bedroom take the largest share. Builder-standard flats often have far fewer, which is why most new flats need electrical additions before the interiors begin.

What is the standard height of a switch board in India?

Common Indian practice places the main switch plate at a room door at about 1100–1200 mm above finished floor, on the latch side of the door and 150–200 mm from the frame. Bedside plates sit lower, at about 700–900 mm, just above the side table, and general sockets at about 300–450 mm. These are practice values rather than code requirements and can be adjusted for accessibility or child safety.

Is an RCCB necessary in a home?

Yes. An MCB protects cables from overload and short circuit, but it does not protect people from electric shock through leakage current. A 30 mA RCCB does, and it is particularly important for bathrooms, kitchens, balconies and outdoor sockets. Most electricians now split a home between two or more RCCB groups so that a single leakage trip does not cut power to the entire home.

Which wire size is used for an AC in a house?

In common practice, a 1–1.5 ton split AC is fed on a dedicated circuit with 2.5 sq mm copper cable and a 16–20 A C-curve MCB, and a 2 ton unit on 4 sq mm cable with a 20–25 A MCB. The final choice depends on the manufacturer's rating, the run length and how cables are installed, so the licensed electrician should confirm it to IS 732.

Should a house have single-phase or three-phase supply?

A small flat with one or two air-conditioners is usually fine on single phase. Larger flats and bungalows with several air-conditioners, a pump, electric cooking or a planned EV charger are often better on three-phase supply, with loads balanced across phases. Thresholds differ by state, so the electrician should confirm the requirement with the local distribution company before applying.

How much does house wiring cost per point in 2026?

At indicative October 2026 rates for new concealed wiring with mid-range branded materials, a light point costs roughly ₹900–1,800, a 6 A socket point ₹1,000–2,000, a 16 A power point ₹1,800–3,500, and a dedicated AC point ₹3,500–7,000. A full 3BHK including the distribution board and earthing typically lands around ₹1.5–3.5 lakh, excluding light fittings and fans.