Choosing the wrong distribution board is one of the most common — and most expensive to fix — mistakes on Nigerian building projects, because it means either running out of circuit ways mid-project or paying for capacity the building will never use. Getting it right comes down to four decisions: way-count, phase configuration, IP rating, and brand, in that order.
Step 1: Work out how many ways you actually need
Count every final circuit the board will feed — lighting circuits, socket circuits, and dedicated circuits for major appliances — then add at least 20% spare ways for future expansion.
A 3-bedroom flat typically needs a 12-18 way board once lighting, sockets, kitchen, water heater, and AC circuits are all accounted for. A small office floor often needs 24-36 ways. Underestimating way-count is the single most common DB sizing mistake Fembosco sees on residential projects, because contractors size for the current fit-out and forget the client will add AC units or a home office within two years.
Step 2: Confirm single-phase or three-phase
Residential and small commercial units on a standard supply are almost always single-phase; larger commercial floors, industrial units, and anything running three-phase motors or heavy AC plant need a three-phase board.
This is usually dictated by the incoming supply from the transformer or generator rather than a free choice at DB level — check what phase configuration is arriving at the building before specifying the board.
Step 3: Match the IP rating to where the board will sit
IP42 boards suit dry indoor locations like a utility cupboard or plant room; IP65 boards are required for outdoor locations, generator houses, and any factory floor exposed to dust or water.
- IP42 — indoor, dry, protected space (most residential and office DBs)
- IP54/55 — indoor but dusty or lightly exposed industrial areas
- IP65 — outdoor, generator rooms, factory floors, coastal humidity
Step 4: Decide on brand — does it actually matter?
For most projects, the brand choice comes down to what’s specified in the consultant’s BOQ or what the contractor standardizes on — Legrand and ABB are the two most widely available and serviced brands in Nigeria, and both meet the same core safety standards.
Where it matters more is sourcing: buying from an authorized distributor like Fembosco protects against the counterfeit and grey-market boards that circulate in open electrical markets, which can fail safety testing despite carrying a real brand name on the casing.
Frequently Asked Questions
Can I add extra ways to a distribution board later?
Only if the enclosure was sized with spare capacity from the start — this is why Fembosco recommends specifying at least 20% spare ways at purchase rather than trying to expand a fully-populated board later.
Does a bigger distribution board cost significantly more?
Moving up a few way-counts adds relatively little to the total cost compared to the labour cost of replacing an undersized board later, so it’s rarely worth cutting the way-count too close to current need.
Conclusion
The right distribution board is the one sized for what the building will need in three years, not just what it needs on handover day — get the way-count and IP rating right first, then choose a brand you can source reliably.