The distribution board (DB) is where power from the meter is split into circuits, each protected by its own breaker. If a circuit overloads or shorts, the breaker trips before the wire overheats. A good DB with correctly rated breakers is one of the most important safety purchases in a house.
Types and specifications
| Item | What it is | Typical use |
|---|---|---|
| Distribution board (DB) | Metal or plastic enclosure, sized by number of "ways" (breaker slots) | Main DB and sub-DBs per floor or portion |
| Surface vs flush DB | Mounted on the wall or recessed into it | Flush for finished interiors; surface for utility areas |
| MCB (miniature circuit breaker) | Trips on overload or short circuit | One per circuit: lights, sockets, AC, geyser |
| Main isolator / main breaker | Switches off the whole board | Incoming supply to each DB |
| Earth leakage protection (RCD/RCCB/ELCB) | Trips when current leaks to earth | Protects people from shock |
| Changeover switch | Switches between grid and generator/UPS/solar | Homes with backup power |
| Surge protection device | Limits voltage spikes | Sensitive appliances, solar systems |
| Busbars, neutral and earth links | Internal connections | Inside every DB |
Breakers come in different current ratings and single- or multi-pole versions. Ratings must match the wire size and load; this is your electrician's job.
Standards
PSQCA's published list of mandatory electrical items does not include circuit breakers or distribution boards (PSQCA list). Check printed ratings and manufacturer details on each item, buy from original stock, and follow your electrician's specification.
Quality checks on delivery
- Sealed boxes with the maker's details.
- Ratings printed clearly on every breaker: current rating, number of poles and breaking capacity.
- Toggle action: firm on and off, no looseness.
- Test button present on earth leakage devices.
- DB enclosure: sturdy, doors close properly, knockouts for cables, earth terminal present.
- Busbars and links included as ordered.
- Count and match against the invoice and the electrician's list.
How much you need
The number of DBs and breakers comes from your electrical design: how many floors or portions, how many circuits, and which heavy appliances get dedicated circuits. Ask your electrician for a schedule listing each DB, its ways, and each breaker's rating. Order a DB with a few spare ways for future circuits.
Bulk-buying tips
- Buy against the schedule, not a rough total.
- Flush DB boxes are needed early, before plaster; breakers can come later.
- One make for all breakers in a DB keeps fit and busbar compatibility simple.
- Keep breakers boxed until fitting to avoid dust and damage.
- Invoices with ratings help at testing and handover.
- Agree returns for sealed unused items.
What affects the price
- DB size (number of ways), material and surface vs flush.
- Breaker type, rating and number of poles.
- Earth leakage protection and surge devices.
- Quality tier and origin.
- Order volume and payment terms.
Ask for a dated, itemised written quote.
Common buying mistakes
- A DB with no spare ways. Future ACs, solar or an extra portion will need new circuits; a full board means replacing it.
- One breaker for many heavy loads. Each AC, geyser or heavy appliance is usually best on its own circuit and breaker.
- Leaving out earth leakage protection to save money.
- Buying flush DBs late. Recessed boxes must be fixed before plaster; ordering them after plaster means cutting walls.
- Mixing makes in one board. Breakers from different makers may not fit the same busbar or rail properly.
FAQs
Do I need earth leakage protection? It protects people from electric shock by tripping when current leaks to earth. Ask your electrician to include it.
Why does my breaker keep tripping? An overloaded circuit, a faulty appliance, a short circuit or a leakage fault. Don't replace it with a higher rating; have an electrician find the cause.
Can I use a higher-rated breaker so it trips less? No. A breaker rated above what the wire can carry lets the wire overheat. Ratings must match the circuit.
Should each floor have its own DB? Many multi-storey homes do, which makes isolation and fault-finding easier. Your electrician will advise based on the layout.