What seems like an electric shock from the floor could be caused by static electricity, a faulty appliance, damaged wires under the floor, and damaged cords on the ground. This post will go into more detail about the different reasons why someone would get a shock.
What Is An Electric Shock Exactly?
An electric shock occurs when electrical current travels through the body, along the skin and through organs, from a point of high electrical potential such as a wire that someone is touching and a point of low potential (the ground).
This could be someone’s feet touching the ground, but it could also be someone touching an appliance or structure which is better earthed. An example of this would be a metal kitchen bench.
What seems like an electric shock from a floor could be a result of two different scenarios.
Two Scenarios
The first scenario is that there is nothing ‘electric’ about the floor. Instead, the floor is the earth and when contact with it is made with a faulty appliance (such as a toaster, refrigerator or light switch) current flows resulting in a shock.
The second scenario is that there is indeed an electrical fault somewhere in the floor. As a result, the floor or parts of the floor may have become electrically live due to faulty wires or appliances touching it.
Protection From A Shock
In both scenarios, an electric shock has the potential to cause serious harm. This is why protective devices and systems need to be installed in the home to protect people should the risk of electric shock occur.
Examples of protective devices include residual current devices (RCDs). These are designed to automatically cut off power to a circuit when the risk of electric shock appears.
An RCD detects when electrical current is leaking to earth and then operates once a certain threshold is met. In most domestic cases, this threshold is when 30 milliamps of current is detected for 300 milliseconds. Interestingly, this is the maximum amount of current and time someone can be exposed to an electric shock before experiencing damaging and potentially fatal side effects. This is laid out in the Shock Limits graph shown here.
Appliances and structures that have a conductive material (such as metal frame), need to be bonded to the home’s earthing system. This is to prevent high voltages (which might give someone a shock) from appearing on the conductive surface if there is an electrical fault.
Bonding appliances and structures to earth also helps ensure that RCDs will work correctly.
Finally, people are protected by electric shocks if an appliance is double insulated meaning an appliance is protected by an extra layer of insulation rather than just basic insulation.
Electric Shock From Floor? – Reason #1
Static Electricity
Likelihood: High – if wearing polyester or in a low humidity environment.
The first reason why someone might get a shock from the floor is static electricity. Static electricity is a phenomenon which occurs when charged electrical particles build up on surfaces like clothes and hair. This charge builds up before getting released when contact with an earthed surface happens.
An example of this scenario would be someone sitting on a couch or bed not realising they have a static electrical charge. When they touch the floor it feels like they are getting a shock. Low humidity and polyester clothes are notorious for generating static.
Electric Shock From Floor? – Reason #2
The Floor Isn’t The Cause Of The Shock, An Appliance Is
Likelihood: Low
If someone is holding an appliance or wire containing an electrical fault they won’t receive a shock until they touch the floor.
This may make it seem like the floor is giving a shock but it actually isn’t.
Instead, the cause of the shock is actually the appliance or surface they were touching (such as a dishwasher or freezer).
Electric Shock From Floor? – Reason #3
Damaged Extension Leads On The Ground
Likelihood: Moderate
Extension leads and power cord with abrasions in the insulation revealing exposed wires can cause electric shocks and breakers to trip.
If a cord is lying on the ground someone can either directly or indirectly get a shock. This is especially the case if the floor is of a conductive material or damp allowing current to flow.
Dampness getting into an extension lead could give someone a shock who is nearby.
Electric Shock From Floor? – Reason #4
Damaged Wiring Underfloor
Likelihood: Low
Damaged wiring underfloor can be caused by pests such as rodents and other vermin. A live wire underfloor could give someone a shock especially if the flooring surface is conductive or damp.
Electricians Perspective
The most likely reason why someone will get a shock from the floor is static electricity unless damaged wires can be found under the floor. Damaged leads on the ground and faulty appliances are also possible reasons why this might happen but unlikely for most people in our experience.
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