An electric shock from an oven can be caused by static electricity, oven wear and tear, rodent damage and incorrect wiring. The shock can also be caused by a different appliance where the oven is simply the ‘earth’. In this post I’ll share these five reasons and what you can do about it from an electricians perspective.
Electric Shock?
An electric shock is a sensation which occurs when the body is exposed to electrical current.
This happens when contact is made between a surface containing voltage (such as the oven metal frame or loose wire inside the oven) and earth (your feet touching the ground).
When this connection is made, electrical current travels from the live wire to earth, in doing so it passes through the body’s skin and organs which is why an electric shock is so dangerous.
The severity of an electric shock depends on several factors, such as those laid out in IEC Shock Limits. This graph shows that an electric shock becomes more severe as someone is exposed to higher levels of current. The length of time that someone is exposed to a shock adds to the severity.
The better that someone is connected to earth, the higher the amount of current that can flow. For example, if someone was barefooted, standing on a wet ground when they got a shock, they are likely to get a much, much worse shock than someone who was wearing shoes.
As the graph shows, only small amounts of current are needed to do harm, this can be as low as 30 milliamps. Exposed to this level of current for more than 300 milliseconds can cause severe harm in some people.
This is why RCDs are mandatory in all new electrical installations.
A standard household RCD needs to trip within 300 milliseconds at 30 milliamps of current.
This is to save people from a potentially fatal electric shock if a fault was to occur.
Metal framework must be bonded to the home’s earthing system too. This is to prevent dangerous voltages from appearing on it.
Ovens and hobbs are typically not on RCD because they are directly wired.
Now that we know what an electric shock is, let’s look at why someone might get an electric shock from an oven.
Electric Shock From An Oven? – Reason #1
Static Shock
Likelihood: High – Especially if someone is wearing polyester clothes, has long hair, or the weather currently has low humidity.
Static electricity is a phenomenon where charged electrical particles build up on clothes, skin and hair – especially if there is low humidity in the weather.
This electrical charge gets released when a good earth contact is made..
As the oven’s metal body is connected to the home’s earthing system, touching the oven can result in an electric shock.
When the oven is touched, these charged electric particles are released causing the electric shock.
Electric Shock From An Oven? – Reason #2
Poorly Maintained Oven
Likelihood: High – Especially if the oven is old or hasn’t been well maintained.
Ovens are appliances that get heavy usage in the home. This leads to natural wear and tear over time causing potentially unsafe conditions and hidden dangers inside the oven.
Food debris and oil can build up causing electrical connections to short to earth.
Parts of the oven can break away exposing live wires.
Depending on what has failed it might be possible to replace a single part of the oven or it might be necessary to completely replace the oven.
Electric Shock From An Oven? – Reason #3
Rodent Damage To Wiring
Likelihood: Moderate – higher if there is evidence of rodents in the house.
Rodents are known to chew wires. If these wires make contact with the earthing system it can result in an electric shock if someone touches the oven. Rodents tend to leave signs such as droppings and chewed debris if they are nearby.
Electric Shock From An Oven? – Reason #4
Incorrect Wiring
Likelihood: Low – Unless someone has worked on the oven recently.
This would be a consideration if someone had been doing electrical work on the oven or electrical circuit connected to the oven recently.
This could be another electrician or even the homeowner.
Basically, if wires such as phase and neutral are transposed anywhere in the circuit (incorrectly wired) it can lead to a potentially fatal electric shock.
Electric Shock From An Oven? – Reason #5
Another Appliance Is The Culprit, Oven Is Just The Earth
Likelihood: Moderate – Check whether or not you are touching another appliance when touching the oven.
It is possible that the oven is not the cause of the shock. The oven frame is only acting as the ‘earth’ connection completing the circuit. The oven may seem like it is giving a shock but it is not act.
Check whether or not you are touching another appliance when touching the oven, if so the other appliance could be to blame for giving a shock.
Of course, any nearby appliance would need to be plugged into a wall socket.
An example of such an appliance could be a phone plugged into a charger, a toaster, fridge, microwave etc.
Electrician Perspective
In our experience, the most likely reason someone would get an electric shock from an oven is static electricity buildup on your body or possibly a faulty component in the oven from lack of maintenance or old age. Something else being electrically live is also a distinct possibility. Incorrect wiring from a homeowner trying to install an oven component and rodent damage are less likely but still possible.