Electrical and solar
House wiring and circuit planner
This planner turns a list of what is in the house into a list of circuits, using standard domestic practice: how many lights and plugs share a circuit, which appliances need a circuit of their own, the breaker and cable size for each, and how big the distribution board (DB board) needs to be.
What you need
This calculator works out the figures in your browser, which needs JavaScript switched on. The method below shows how to work it out by hand.
Estimates for planning and budgeting. Real quantities depend on the site and the workmanship, so check with your builder before you order.
The rules are the common ones under SANS 10142-1, which Zimbabwean electricians widely work to: lighting on 10 A breakers with 1.5 mm² cable, plugs on 20 A breakers with 2.5 mm², a dedicated circuit for each geyser, stove, aircon and pump, earth leakage protection (30 mA) on every socket circuit, and spare ways for the future.
It is a planning tool for drawings and budgets. The final design, installation and Certificate of Compliance must come from a licensed electrician, and ZESA will not connect without it.
How it is worked out
- Lighting circuits = light points ÷ lights per circuit, rounded up, each 10 A on 1.5 mm².
- Plug circuits = plug points ÷ points per circuit, rounded up, each 20 A on 2.5 mm², all behind 30 mA earth leakage.
- Each geyser, aircon and other dedicated load gets its own circuit; the stove its own 32 A or 40 A circuit on 6 mm² or 10 mm².
- Board ways = single-pole breakers + 2 for the main switch + 2 per earth leakage unit, plus about 25% spare, rounded up to a standard board size.
What it assumes
- Single-phase supply.
- Pump circuit sized at about 1.25 × its running current.
- Surge protection is recommended and allowed for in the board ways.
Common questions
How many plugs can go on one circuit?
Common practice is up to about 10 socket outlets on a 20 A circuit in 2.5 mm² cable, protected by 30 mA earth leakage.
Does a geyser need its own circuit?
Yes. Each geyser should have a dedicated circuit, typically 20 A on 2.5 mm², with an isolator near the geyser.
How many ways should my DB board have?
Enough for every breaker, the main switch and earth leakage units, plus roughly a quarter spare for additions such as solar, a gate motor or an outbuilding.
Want exact quantities for your plan?
A calculator works one wall or one slab at a time. A bill of quantities works from your actual drawings and counts everything, which is what builders price against and what stops you buying twice.