Understanding Your Electrics — Part 2 of 6
Why Your RCD Keeps Tripping (And When to Worry)
By Frankie · February 2026 · 4 min read
It's one of the most common calls I get: "Frankie, my switch keeps tripping and I can't work out why." Usually it happens at the worst possible time — mid-shower, halfway through cooking dinner, or when you're working from home on a deadline.
The good news? Your electrics are actually doing exactly what they're supposed to. The bad news? Something's causing it, and it won't fix itself.
First — What's an RCD Actually Doing?
Think of your RCD like a very attentive bouncer. It's constantly monitoring the electricity flowing through your circuits, and if it detects even a tiny imbalance — a sign that current is leaking somewhere it shouldn't — it cuts the power in milliseconds. That "leak" could be going through water, through faulty insulation, or worst case, through you. So when your RCD trips, it's not being annoying. It's potentially saving your life.
The Most Common Causes
1. A Faulty Appliance
This is the number one culprit. Kettles, washing machines, dishwashers, and tumble dryers are the usual suspects. Over time, heating elements degrade and allow a tiny bit of current to leak to earth. The appliance might seem to work perfectly fine, but inside it's slowly breaking down.
2. Moisture in an Outdoor Socket
If your RCD trips after heavy rain or when it's particularly damp, check your outdoor sockets, garden lights, or anything in an outbuilding. Water and electricity are not friends.
3. A Worn-Out Immersion Heater or Shower Element
Electric showers and immersion heaters work incredibly hard. Eventually the protective coating breaks down and water gets where it shouldn't. If your RCD trips when you use the shower or hot water, this is likely the cause.
4. Old or Damaged Wiring
If your home was wired before the 1990s and hasn't been rewired, the insulation on your cables may be deteriorating. This is a more serious issue — I'd always recommend getting it checked with an EICR.
5. The RCD Itself
RCDs can become overly sensitive or develop faults as they age. If yours is more than 10–15 years old and trips for no apparent reason, it might be the unit itself.
What You Can Try Before Calling Me
The Unplug-and-Test Method:
1. Switch off and unplug everything on the affected circuit.
2. Reset the RCD. If it stays on, the fault is in one of the things you just unplugged.
3. Plug things back in one at a time. When the RCD trips again, you've found your culprit.
4. If the RCD trips with nothing plugged in, the fault is in the fixed wiring. That's when you need an electrician.
When Should You Actually Worry?
Call an electrician if:
⚠️ The RCD trips immediately every time you reset it
⚠️ You notice a burning smell or discolouration around sockets
⚠️ The RCD trips with nothing plugged in
⚠️ It trips randomly at night when nothing's being used
⚠️ You've got old wiring (pre-1990s) that's never been inspected
The Bottom Line
A tripping RCD is your electrical system doing its job. Don't ignore it, don't keep forcing it back on. And if you try the unplug-and-test method and find the culprit is your kettle, you don't even need me. Just buy a new kettle and save yourself the call-out fee. That's just how I work.
Frankie Sewell
NICEIC Approved Contractor • YRLA Recognised Service Provider • Bright Sparks of York
RCD Keeps Tripping?
If you've tried the steps above and it's still going, give me a ring. Free phone advice — I'll tell you if you actually need me or not.
Understanding Your Electrics — Part 2 of 6