What does electrical arcing sound like?

It sounds like sharp crackling, snapping, or zapping — similar to the sound of a spark gap or static electricity but louder and potentially sustained. It is distinctly different from a smooth hum or buzz.

Can arcing happen behind walls?

Yes, and this is one of the most dangerous scenarios. Arcing in concealed wiring can smoulder for hours before becoming a visible fire. If you hear crackling from within a wall, turn off the circuit and call an electrician urgently.

An Arc Fault Detection Device monitors the circuit for the electrical signature of arcing and disconnects the power if it detects one. BS 7671 18th Edition Amendment 2 recommends them for higher-risk locations such as bedrooms and escape routes. They provide fire protection that MCBs and RCDs alone cannot.

Can arcing be intermittent?

Yes. Arcing often starts as an intermittent fault — crackling briefly when a particular appliance is used or when vibration moves a loose connection. It tends to get worse over time as the arcing damages the connection further.

Is it safe to sleep in the house if I hear arcing?

If you can identify and isolate the circuit at the consumer unit, the risk is eliminated for that circuit. If you cannot locate the source, it is safer to turn off the main switch overnight and call an electrician first thing in the morning. Ensure your smoke alarms are working.

High risk

Updated 30 August 2026

Electrical Arcing Or Crackling Sound

You can hear a crackling, snapping, or zapping sound coming from your electrics.

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What's happening?

An electrical arcing or crackling sound is the noise made when electricity jumps across a gap between two conductors. It sounds like a sharp crackling, snapping, or zapping — similar to static electricity but louder and more sustained. Arcing occurs where connections are loose, contacts are worn, or insulation has broken down. It is distinct from a hum or buzz and indicates a more active and dangerous fault.

What usually causes it?

Loose connection at a socket, switch, or junction box creating intermittent arcing
Worn switch contacts arcing when operated or under load
Damaged cable insulation allowing conductors to arc through the gap
Carbon tracking on the surface of a socket or switch (conductive path formed by previous arcing)
Failing MCB or RCD arcing internally
Water or moisture creating a conductive path between live parts

Is it dangerous?

Yes, very dangerous. Electrical arcing generates temperatures of 3,000 to 20,000 degrees Celsius. At these temperatures, surrounding materials — timber, insulation, plasterboard, plastic — can easily ignite. Arc faults are particularly dangerous because they can occur inside walls, behind sockets, and in ceiling voids where they cannot be seen. If you hear crackling from your electrics, take it seriously and act quickly.

Can I fix it myself?

No. Try to identify where the sound is coming from. If it is a specific socket, switch, or fitting, stop using it. If the sound comes from the consumer unit, do not touch it — turn off the main switch if you can safely do so. If the sound is in a wall, turn off the circuit serving that area. Call an electrician promptly.

When should you call an electrician?

Call an electrician the same day. If the arcing is continuous, loud, or accompanied by burning smell, smoke, or visible sparks, treat it as an emergency. An arc fault can transition to a fire within minutes if the conditions are right. Do not wait to see if it stops on its own.

What will the electrician actually do?

Systematically locate the source of the arcing using testing and inspection
Use thermal imaging to identify hotspots if the sound is coming from within a wall
Isolate the affected circuit and dismantle the faulty fitting or connection
Repair or replace the connection, fitting, or cable section where arcing is occurring
Test the circuit for insulation integrity after the repair
Advise on the installation of an AFDD (Arc Fault Detection Device) for ongoing protection