Plug socket sparks when switched off?
This tends to be caused by an appliance generating what is called a ‘back EMF’ when power to the circuit is switched off. This ‘back EMF’ is what causes the sparks. The back EMF is due to energy held in the windings of an appliance that gets released when the switch is turned off.
This could also be a sign of a faulty plug socket. Over time the switches on plug sockets can become worn due to wear and tear. This leads to sparking between the electrical contacts of the plug socket.
This post will go into why the plug socket sparks when switched off and what you can do to fix it.
Is It Dangerous When The Plug Socket Sparks?
Normally, tiny sparks happen when a switch is pressed. But if there are large or ongoing sparks then that’s more serious and should be addressed as soon as possible.
Plug Socket Sparks When Switched Off? – Reason #1
Loose Connection In The Power Outlet
The first reason is a loose connection in the power outlet.
The wires behind the power outlet can become loose resulting in sparking when the plug socket is turned off or on. As the wires aren’t tightened properly, the voltage jumps when the plug socket is switched. This is the spark that you can see. Loose wires can sometimes be fixed by reconnecting the wires. In most cases, the best course of action is to replace the power outlet.
Plug Socket Sparks When Switched Off? – Reason #2
Faulty Rocker Switch
The next reason why the plug socket sparks when switched off is a faulty rocker switch. This can cause the switch to behave in a weird way. You will notice that the switch feels difficult or uneven to press, compared to other switches around the house. This is because the mechanical part of the switch which includes plastic components, springs, and electrical contacts has failed. These contacts then begin to spark. The best solution is to replace the power outlet with a new one.
Plug Socket Sparks When Switched Off? – Reason #3
Back Voltage From Appliance
A back EMF is a short release of energy when an appliance with a winding is turned off.
What Are Windings?
Windings are found in many common household appliances, including electronics.
It is a coil of wire which generates a magnetic field when current passes through it.
Basically, windings are how we can get electricity to do useful ‘kinetic’ work like turning a shaft of a motor. It’s how we convert electrical energy into movement and magnetism is how it does that.
When the power is on, the windings store a charge. When the power is switched off, this charge gets released back into the circuit.
This can appear as a spark when a switch is turned off.
Appliances that have windings are what’s called an ‘inductive load’.
Normally, appliances are supposed to have a discharge path for this back EMF so that it can be released safely without causing a spark.
If you suspect the appliance is generating a back EMF, try plugging it into another wall outlet to see if it does the same thing.
If the plug socket sparks when switched off, it might indicate the appliance has faulty electronics or was made in a place where there are less regulations around discharging back EMF. The best thing to do is to consult the warranty for the appliance.
Next Steps
Plug socket sparks when switched off? First, check the plugged in appliance. It might be generating a back EMF which is causing the spark. Consult with your warranty provider for the appliance to see what they recommend. Secondly, there might be a loose connection in the power outlet or potentially a faulty rocker switch. Replacing a plug socket is a cheap way to resolve the problem.