After a storm or flood: When you should NOT turn your home's power back on

After a storm or flood, it is tempting to turn the electricity back on as soon as the public supply returns. That can be dangerous. If floodwater, mud or heavy moisture reached electrical installations, the home's system should not simply be energised again.

The most important rule is simple: never step into water to reach a consumer unit, socket or electrical appliance. Water may be energised even when there is no visible sign. If the main switch can only be reached through a wet or flooded area, stay away and contact the emergency services, network operator or a qualified electrician.

If you safely switched the power off before water entered, leave it off while electrical components are wet or contaminated. This includes consumer units, distribution boards, sockets, switches, wiring connections, heat pumps, heating equipment, inverters, battery storage systems and permanently connected appliances.

Even after the water has gone, a dry-looking surface does not automatically mean the system is safe. Moisture can remain inside enclosures, cables, terminals and electronics. Mud and contaminated water can leave conductive deposits that later cause short circuits, leakage current or fires.

Distribution boards and protective devices deserve special attention. If a board was directly exposed to water, it should be inspected by a qualified electrician before it is energised again. The same applies to appliances that stood in water. Letting equipment dry and then plugging it back in is not a reliable safety test.

Solar installations require extra caution. Even when the public grid is off, solar panels can produce DC voltage in daylight. Flooded inverters, batteries or DC wiring should not be touched or opened by householders. A qualified solar or electrical contractor should inspect the installation.

If the storm damaged your property without flooding the electrical system, still look for obvious problems such as damaged service cables, broken outdoor sockets, wet distribution equipment or lines hanging near the building. Do not touch suspicious equipment and keep well away from downed lines outside.

Power should only be restored when the installation is known to be dry, undamaged and safe. After significant storm or water damage, that decision should be made by a qualified electrician. When power is restored, leave large appliances off initially and bring equipment back online gradually.

A common mistake after flooding is to assume that once the utility restores the area, the electrical system inside the house must also be safe. The network operator can only restore the public grid. Damage to your own sockets, wiring and equipment has to be assessed separately.

The rule is straightforward: if water reached electrical equipment, or if damage cannot confidently be ruled out, keep the power off. A few extra hours of caution are far better than an electric shock, short circuit or fire.