Almost every commercial and residential building in Nigeria running a generator needs a changeover switch to keep mains and generator power from ever connecting at the same time — the real decision is whether that switching needs to happen automatically or whether someone operating it manually is good enough.
What does a changeover switch actually prevent?
A changeover switch physically prevents the mains supply and a backup generator from being connected to the building’s electrical system simultaneously, which would otherwise risk feeding power back into the grid and endangering utility workers, as well as damaging equipment.
This isn’t optional safety equipment for any building running a generator alongside a mains connection — it’s a basic requirement regardless of building size.
When is a manual changeover switch good enough?
A manual changeover switch is sufficient wherever someone is reliably on-site to operate it during a power outage, which covers most Nigerian residential and small commercial installations.
The tradeoff is a short delay between mains failure and someone physically switching to generator, and the switch being left in the wrong position if no one is available at the moment of an outage.
When does a building need an automatic transfer switch (ATS) instead?
An ATS is required wherever a delay in switching to generator power is unacceptable — hospitals, data centres, and any building or process that can’t tolerate even a brief interruption need automatic switching rather than relying on a person to notice and act.
- ATS senses mains failure and switches to generator automatically, without operator action
- ATS also switches back to mains automatically once utility power is restored
- Higher cost than manual, but removes human response time from the equation entirely
How is the changeover switch sized?
A changeover switch should be sized to the building’s actual maximum demand and the generator’s output capacity, not just the rating of the incoming mains breaker, since undersizing against real peak load causes failures under actual operating conditions.
Fembosco’s technical team confirms both figures before recommending a switch size, rather than sizing off the mains breaker rating alone.
Frequently Asked Questions
Can a changeover switch be retrofitted to an existing building?
In most cases yes — it’s fitted at the main incomer point ahead of the existing distribution board without requiring a full rewire, though this should be confirmed on site.
Does Fembosco install the changeover switch, or supply only?
Fembosco supplies the switch and can coordinate installation through its panel-building and site engineering team on request.
Conclusion
Manual switching is a legitimate and cost-effective choice for most residential and small commercial buildings with someone on-site; move to an automatic transfer switch specifically where an outage delay is genuinely unacceptable, not as a default upgrade everyone needs.