Electric Water Heater (Termo Eléctrico) Trips the Breaker or RCD: Causes & Repair
Your home loses power and the RCD switch refuses to stay up. As soon as you unplug the electric water heater (termo eléctrico) in the bathroom or utility room, the electricity comes back on—but plugging it back in trips the breaker again. This is the #1 failure in electric water heaters after 3 to 5 years of use.
Why the Water Heater Trips the RCD
Inside the tank, a 1,200W–2,500W heating element heats the water. Once the sacrificial magnesium anode wears away, limescale and electrolysis corrode the metal sheath of the heating element.
When a microscopic crack forms, water touches the live internal filament. Current leaks into the water and down the Earth wire, causing the 30mA RCD to trip instantly so you don't get electrocuted in the shower.
Dry Ceramic Element vs. Wet Immersion Element vs. Leaking Tank
1. Dry steatite (ceramic) element inside a sleeve: can be replaced in 20 minutes without draining the tank.
2. Wet immersion element: requires draining the tank, removing the flange, cleaning out limescale, and fitting a new element, gasket and magnesium anode.
3. Rusted tank dripping water onto the thermostat: if rusty water is leaking from the inner cylinder onto the bottom wiring cover, the tank itself is perforated and the unit must be replaced.
Our 24/7 emergency plumbers and electricians in Barcelona, Badalona, Girona and Sabadell repair heating elements or install a brand-new water heater the same day. Call 936 94 00 23.
FAQ
Is it safe to shower using the remaining hot water if I unplug the heater?
Yes, as long as the power plug is physically unplugged from the wall socket, there is zero voltage in the tank. Never disconnect the green-yellow Earth wire to stop the breaker from tripping—that would electrify your shower water at 230V.