An electric shock from a hot tub could be caused by static electricity or a nearby cord or appliance with a fault. This post will attempt to cover two reasons why someone might get a shock in a hot tub.
What Is An Electric Shock?
An electric shock is an unpleasant sensation that occurs when contact is made between a surface with high electrical potential (voltage) and a surface with low electrical potential (the ground).
When this situation happens, a circuit is made allowing current to flow.
Current travels from the surface or wire with voltage, through the body to earth. When current passes through the body the body feels this as a painful shock.
The longer that someone is exposed to a shock and the higher the current, the more dangerous it can be.
As electric shocks have the potential to cause severe bodily harm, residual current devices (RCDs) must be installed in the home.
They ensure that power will get shut off to a circuit when a certain ‘electric shock’ leakage current is met. For standard RCDs this is 30 milliamps of current within 300 milliseconds (0.3 seconds). When an RCD trips in this time, it should prevent any long term damage from occurring (according to Shock Limits).
Should A Hot Tub Be Bonded To Earth?
If a hot tub is made of a conductive material (not ceramic), it should be bonded to the home’s earthing system. This will prevent dangerous voltages from appearing on the hot tub. A bonding wire is just an earth wire fixed to the tub leading back to the earth bar in the switchboard. Gas pipes and water taps also need to be bonded to earth.
Wet Area Zones For A Hot Tub
As hot tubs are located in wet areas all electrical appliances and fittings must be correctly rated for potential water exposure.
If the wrong electrical fittings are installed in a damp zone (such as a power outlet near a water container), there is a big risk of getting an electric shock.
The area around a hot tub can be separated into different zones for wiring purposes (taken from ASNZS:3000).
Each zone specifies what is and isn’t allowed to be wired.
Zone 0 – the interior of the hot tub
Zone 1 – 1.2m radius from the fixed plumbing connection and 2.25m above the floor
Zone 2 – 0.6m external to zone 1
Firstly, wall sockets must be at least 300 mm from the floor. If a wall socket is closer, then splash onto the wall socket can definitely cause a shock.
Light fittings must be of an IP X4 rating if located in zone 1 or zone 2. Any less than this and there is risk of an electric shock.
Electric Shock From A Hot Tub – Reason #1
Nearby Lights, Switches, Power Points Adjacent To The Hot Tub
Likelihood: Moderate – if the bathroom is old or not up to standard electrically.
As discussed earlier with ‘wet areas’, if you have a 230 volt light or power point beside the hot tub, then that could cause an electric shock.
It is a good idea to identify any electrical fittings near and around the hot tub. This could be power points, switches, appliances, lights and extension leads.
Any of these could be the reason why someone is getting a shock.
As water is a conductive substance and areas around hot tubs tend to become very humid, it is possible that a rogue powerpoint, switch, appliance, or light could be the source of the problem.
Electric Shock From A Hot Tub – Reason #2
Static Electricity
Likelihood: Moderate
Static electricity is a charge that builds up on clothes and hair. This charge grows until it releases causing an electric shock. If someone had a static charge on their clothes then touched a hot tub, they could get a good electric shock.
Electricians Perspective
Water makes it easy for electricity to travel. A nearby wall socket, power cord, or appliance might be the culprit. Because hot tubs are located in a ‘wet area’, it’s important to check if any wall sockets, switches, light fittings and appliances are located nearby. Any of these could be the reason for getting a shock.
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