Why Does My RCD Keep Tripping? Common Causes Explained

August 4, 2026

An RCD that keeps tripping can be frustrating, particularly when it switches off several sockets or appliances at once. However, the device is not simply being temperamental. It may have detected an electrical fault that requires attention.

The problem can become more noticeable during summer, when people use more lawnmowers, pressure washers, outdoor lighting, pond pumps and other garden equipment. Moisture, damaged cables and faulty appliances can all cause an RCD to operate.

Here are the common reasons an RCD keeps tripping, the checks you can safely make and when you should call a qualified electrician.

What Is an RCD?

RCD stands for Residual Current Device. It is a safety device normally located inside your consumer unit, which many people still refer to as a fusebox.

An RCD monitors the electricity flowing through one or more circuits. If it detects electricity flowing somewhere it should not, it quickly disconnects the supply. This reduces the risk of serious electric shock and electrical fire.

An RCD is different from a standard circuit breaker. A circuit breaker usually responds to an overload or short circuit, while an RCD looks for electrical leakage. Some modern consumer units use RCBOs, which provide both forms of protection on individual circuits.

Why Does an RCD Keep Tripping?

There are several possible causes. In some cases, a single appliance is responsible. In others, the fault may be within the electrical installation itself.

A Faulty Appliance

Faulty appliances are among the most common causes of repeated RCD tripping. Washing machines, dishwashers, kettles, ovens and fridge-freezers can develop electrical leakage as components wear out.

Appliances containing heating elements are frequent culprits because an ageing or damaged element can allow current to escape to earth.

The appliance may continue working normally most of the time, only causing the RCD to trip during a particular part of its operating cycle.

Damaged Garden Equipment

Summer often brings an increase in RCD problems because more electrical equipment is being used outside.

Possible causes include:

  • A damaged lawnmower or hedge trimmer cable
  • Water entering a pressure washer connection
  • A faulty pond or swimming pool pump
  • Damaged outdoor lighting
  • Moisture inside an outdoor socket
  • An extension lead left outside or used in damp conditions

Electrical equipment used outdoors should be suitable for its environment and protected by an RCD. Never use damaged equipment or ordinary indoor extension leads in wet conditions.

Moisture or Water Ingress

Water and electricity are a dangerous combination. Moisture inside an outdoor socket, light fitting, junction box or electrical appliance can cause leakage and trip the RCD.

The fault may appear after heavy rain, garden watering, cleaning or a period of high humidity. Condensation can also affect electrical equipment in garages, sheds and other unheated buildings.

Do not attempt to open or dry out electrical fittings yourself. If water may have entered part of the installation, leave the affected circuit switched off and arrange an inspection.

Several Appliances Creating Leakage

Electrical appliances naturally produce very small amounts of leakage current. Normally, this is well below the level that causes an RCD to operate.

However, when several appliances are connected to circuits protected by the same RCD, their combined leakage can become high enough to cause intermittent tripping. This is more common in homes with older consumer units where one RCD protects numerous circuits.

An electrician can test the individual circuits and appliances to identify where the leakage is coming from.

Damaged Wiring or Accessories

Loose connections, deteriorated cable insulation, damaged sockets and incorrectly installed electrical work can all result in an RCD tripping.

Damage may be caused by age, building work, rodents, heat or a screw or nail driven into a concealed cable. The fault may only become apparent when a particular socket, light or appliance is used.

A Faulty RCD

RCDs can occasionally become faulty, particularly as they age. However, the device should not automatically be blamed or replaced before the circuits it protects have been properly tested.

Replacing an RCD without identifying the underlying cause could leave a potentially dangerous electrical fault unresolved.

What Can You Safely Check?

If there is no smell of burning, visible damage, water near the electrics or other immediate danger, you can make a few basic observations.

Unplug portable appliances connected to the affected sockets, particularly anything that was being used when the power went off. You can then try resetting the RCD once.

Reconnect the appliances individually. If the RCD trips immediately after one particular appliance is connected or switched on, leave that appliance unplugged and arrange for it to be repaired or replaced.

If the RCD will not reset when the appliances are unplugged, the problem may involve fixed equipment or the wiring. This requires professional fault-finding.

Never repeatedly force an RCD back on, hold the switch in position or attempt to bypass it. Do not remove the consumer unit cover or dismantle electrical accessories.

When Should You Call an Electrician?

Contact a qualified electrician if:

  • The RCD trips repeatedly
  • It will not reset
  • You cannot identify the appliance causing the problem
  • The problem started after building or DIY work
  • An outdoor circuit trips following rain
  • A socket, plug or consumer unit feels unusually warm
  • You notice scorching, crackling or a burning smell
  • Someone receives an electric shock or tingling sensation
  • The property has an old consumer unit or limited RCD protection

Electrical Safety First advises that repeated RCD tripping is likely to indicate a fault with an appliance or the wiring and should be investigated by a registered electrician.

How Will an Electrician Find the Fault?

Electrical fault-finding involves more than simply resetting the consumer unit. An electrician may test the RCD, measure leakage, inspect the affected circuits and carry out insulation resistance testing.

This helps establish whether the problem is caused by an appliance, damaged wiring, moisture, a faulty accessory or the RCD itself. Once the source has been found, the electrician can recommend the correct repair instead of relying on guesswork.

Electrical Fault-Finding in Chelmsford and Essex

If your RCD keeps tripping, do not ignore it. The occasional interruption might appear harmless, but repeated tripping usually means something needs investigating.

Complete Electrical Services provides professional electrical fault-finding and domestic electrical repairs throughout Chelmsford, Writtle and the surrounding areas of Essex.

To arrange an inspection, call 01245 422 306 or 07968 991 787, email info@completeelectric.co.uk, or contact Complete Electrical Services online.