How to draw an electrical plan for a house, step by step
Seven steps from the floorplan to the PDF the client signs: get the drawing, list what each room needs, place the symbols, group the circuits, draw the wiring, check it, export it. With a figure for each.
To draw an electrical plan for a house, start from a floorplan to scale, list what each room needs, place the standard symbols on the walls and ceilings, group the devices into circuits from the board, draw the wiring from each switch to its light and along each circuit, run the three checks, and export a PDF with its legend. Seven steps, in the order that avoids drawing it twice.
The seven steps
- Start from the floorplan you have.
- Walk the rooms and list what each one needs.
- Place the symbols.
- Group the devices into circuits.
- Draw the wiring.
- Check it before anyone sees it.
- Export and share, and keep the editable plan.
1. Start from the floorplan you have
Everything sits on the floorplan, so get the best one available. An architect's PDF is ideal: it is to scale and the walls are where they will be. A photograph of a paper drawing works, taken square on in good light. With no drawing at all, measure the rooms and draw the walls on a grid, or scan them: a recent iPhone with LiDAR produces a floorplan with the dimensions on it in half an hour.
Write the scale on the plan, or make sure the drawing carries it. Symbol sizes and wire lengths mean nothing without it.
2. Walk the rooms and list what each one needs
Before placing a symbol, go room by room with the client or the brief and write down what each room needs: how many sockets and where the furniture will be, which lights and from where they are switched, which fixed appliances need a feed of their own. Kitchens take the longest: the cooker, the hob, the dishwasher, the fridge, the extractor, the under-cupboard lights, the sockets above the worktop.
Your regulations decide the minimums, the number of sockets in a room, the protection a bathroom circuit needs, the height of switches. The plan does not replace them. It is where you apply them.
3. Place the symbols
Put the list on the plan with the standard symbols, so the drawing reads the same to the next person: a socket is a socket mark, a switch a switch mark, a light a crossed circle. The symbols chart has all of them in both conventions.
- Ceiling light
- 1-way switch
- Double socket
- Distribution board
- C1, lighting
- C2, sockets
Three habits save time later:
- Keep wall devices on the wall. A socket sits on the wall line with its open side into the room; a switch goes beside the door on the handle side.
- Label as you go. S1, S2, L1, SO1. Labels tie the plan to the schedule and make the next step possible.
- Size the symbols to the plan. On a whole house at 1:100 the symbols must be small or they hide the walls. On a single room they can be bigger.
4. Group the devices into circuits
A house is wired as a set of circuits from the distribution board, and the plan should show which device is on which. The usual split: lighting circuits, often one per floor; socket circuits, one or more per floor, with the kitchen's sockets on their own; and dedicated circuits for the cooker, the shower, the immersion heater, the EV charger, anything that takes a lot of current on its own.
Give every circuit a reference, C1, C2, C3, and a colour. Colour the symbols with their circuit and the plan explains itself: the client sees that the kitchen sockets are separate, and the person wiring it sees where each run ends.
5. Draw the wiring
Draw the runs from the board to the devices, and between devices on the same circuit. The plan does not show every cable in the wall; it shows what connects to what. Two things matter:
- Switch to light. Every light's switch is drawn to its light, and a two-way pair to each other and to the light they share. It is what the client checks first and what the simulation tests later. The two-way switching article shows the pair.
- One run per connection. A device appears once on its circuit. Nine wires meeting at one light means the drawing is wrong, not the house.
6. Check it before anyone sees it
A plan that looks finished can still be wrong in three ways: a device that reaches no circuit, a switch that controls nothing or the wrong thing, and a circuit with more on it than its breaker can carry. Each is easy to test once the plan is drawn, and the checking article lets you try all three. Do the checks before the plan goes to the client, not after.
7. Export and share
The plan the client receives should be the one you drew, with a legend that explains the symbols and the circuits, dated, on a page that prints on A4 or Letter without cutting anything off. A PDF does this; an image works for a quick message. Keep the editable plan: the client will change their mind at least once, and the second version should take minutes.
Common mistakes
- Drawing before listing. Symbols placed from memory get moved twice. The list from step 2 is the plan's brief.
- Symbols the wrong size. Too big and they hide the walls; too small and the client cannot read them. Set the size for the whole sheet once.
- Circuits that exist only in your head. Without references and colours the plan is a picture of devices, not a plan of an installation.
- A legend that does not match the sheet. The legend should be built from what is on the plan, every time it is exported.
- Redrawing for each revision. Keep one editable plan and export it again. A redrawn plan drifts.
Questions
What scale should a house electrical plan be?
Whatever the floorplan is, usually 1:50 or 1:100. What matters is that the scale is on the sheet, so that distances between devices and the lengths of runs mean something.
Do I need an architect's drawing?
No. A measured sketch of the walls on a grid is enough for most domestic work, and a 3D scan on a phone gives a scaled floorplan without measuring. An architect's PDF is the best start when there is one.
How detailed should the wiring be?
Show what connects to what: each switch to its light, each device along its circuit, each circuit back to the board. The route of every cable in the wall belongs on site, and the terminals belong on a wiring diagram, not on the plan.
Which software draws electrical plans?
CAD programs do, with electrical symbol libraries, and they suit an office. On site, an app that places the symbols on a photo or a PDF of the floorplan and lets you wire them with a finger is faster. ePlan is one, on iPhone, iPad, Mac and in the browser, and this article is the order it is built around.