Mild electric shocks or tingles might not be taken seriously, but they can turn into lethal full mains voltage shocks at any time – so never use any appliance you get a mild shock from. Disconnect it immediately. The reason you get shocks from a washing machine, or any other appliance, is because it is not earthed properly.
All large appliances need to be connected to earth for safety. The earth wire runs down the mains cable and then through the socket it is plugged into. If this connection becomes broken at any point in the machine, cable, plug or wall socket, then you can get the symptom of mild electric shocks. A relatively mild shock can happen even if the washing machine is otherwise in perfect working order due to an electrical phenomenon where current is induced into the earth wire if it’s disconnected. You don’t need to understand this bizarre phenomenon but you do need to understand that at any time a real insulation fault could occur in the machine which would turn this mild induced current to full mains voltage.
How to stop the electric shocks
The appliance needs to be properly earthed so the solution is to find out why it isn’t. Here are general things to check. If they don’t stop the problem get an engineer out as soon as possible.
The first suspect is the wall socket. Try plugging the appliance into a totally different wall socket. If the shocks stop the chances are the original wall socket has the fault. Plug-in wall socket testers are available. They can accurately show if there is no earth present but they can’t be relied on to prove that a wall socket is adequately earthed. However, I usually found if one showed no faults then the problem was something else. The earth wire could be disconnected inside or the brass earth prongs inside could be worn or too far apart to grip the earth pin on the plug. Clearly you don’t mess with wall sockets unless you know what you are doing but if you can identify the problem at least you know you need an electrician and not an appliance engineer.
If the appliance is plugged into an extension cable then clearly there could be a problem anywhere on the extension. Try another extension (but make sure it’s appropriate – appliances and extension cables) or try to plug it directly into the wall socket to see if the problem disappears. I have seen appliances plugged into totally inappropriate extension cables that are using 2 core cable with no earth!
If the socket seems ok then check inside the plug to make sure the green and yellow earth wire is connected securely. If it’s OK, then either the earth wire in the mains cable could have a break somewhere inside and needs replacing, or it may not be connected inside the washing machine. The latter is very unlikely, I’ve never known it, but it’s theoretically possible. Both can (and should) be checked with a continuity test meter by checking the continuity between the earth pin on the plug and the metal door hinge or another suitable bare metal point on the washing machine.
Most appliances have long since come with pre-fitted moulded plugs which can’t be checked. The first thing an engineer would check is the continuity down from the earth pin as described above. If he had a good reading he wouldn’t need to look inside the plug. If the reading was open circuit or very high resistance, but the earth was connected properly inside the machine he’d cut off the plug about an inch down and replace it. If that failed to make a difference he’d replace the mains cable.
Why Does an unearthed appliance cause shocks?
The shocks are often mild, or just tingles because they are caused by small amounts of electricity leaking or inducing across to the disconnected earth wire and running through the casing. It's a phenomenon related to eddy current, but it's not necessary to understand the scientific reason. The effect is useful to us though because without it we would be unaware the earth is not connected unless conditions later allow a full electric shock, which could be fatal.
Such an appliance poses a serious danger. As the shocks indicate that the washing machine is not earthed it means that if a component inside the machine's insulation breaks down, or a live wire comes adrift and touches the metal parts inside, then the low voltage current will be replaced by the full mains voltage which can kill. Without a path to earth, the washing machine cannot blow the fuse and instead could just work as normal but be lethal.
Don’t confuse with static electricity discharges
This article is about receiving electric shocks from an appliance. If you get just a single short shock when you touch an appliance (possibly accompanied by a cracking sound) which doesn’t reoccur when you touch the appliance again this could be static electricity discharging from your body and is very different to this issue.
Quick test for an Unearthed Appliance
This is quite a crude test. And I can’t recommend it as being definitive. However, whenever I suspected an appliance might not be earthed I used to use a neon screwdriver (that lights up when it detects electricity). By placing the blade of the driver on the bare metal somewhere on the casing it would usually light up if the appliance wasn’t earthed. Obviously this is picking up the electricity that is running through the appliance. A good place for this test is a door hinge (as long as it is unpainted). But basically as long as you know that you are touching bare metal on the casing you should be able to pick up the electricity running through if it is not earthed. Remember if you can pick up electricity like this, then the appliance is dangerous, and needs disconnecting until fixed.
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