Advice on fatal current (research project)

[JLR111]

Hello,

This question is purely for research purposes.

In the event that an appliance (hairdryer) was dropped into a bath with a person on it, and a circuit breaker was tripped in the consumer unit, could this shock still prove fatal or would the breaker save their life? I know that this is the purpose of the breaker, but have heard of these incidents occurring and wondered what sort of fatality rate we're looking at.

Again, this is purely for academic curiosity. Many thanks for your help!

 

[telectrix]

a RCD would, hopefully protect. A MCB will not. MCBs are to protect against faults in the installation, e.g. short circuit ot overload. fatal levels of current are way way far below the tripping threshold of a MCB (breaker).

 

[davesparks]

What type of breaker? An MCB or an RCD?

Is this a UK standard mains supply or another country? Having a hair dryer in the bathroom implies another country as generally sockets are not installed in UK bathrooms.

Is the electrical installation assumed to be in good condition?

My gut reaction is to say that the person in the bath is unlikely to receive any sort of electric shock, both the live and neutral of the hairdryer will be submerged in the water and I would expect the majority of current to flow from one to the other. I suspect that the person would be at more risk of a shock if they were to touch the metal taps (if the are bonded) or possibly if they were to get out of the bath and put one foot on the floor whilst the other is in the bath they may receive a shock.

I also doubt that enough current will flow to operate a circuit breaker, depending on what chemicals are in the water. An RCD will likely operate if there is any path to earth for current to flow.

 

[Moley]

I would add that you should make sure her life insurance is up to date and that you have a good alabi

 

[JLR111]

What type of breaker? An MCB or an RCD?

Is this a UK standard mains supply or another country? Having a hair dryer in the bathroom implies another country as generally sockets are not installed in UK bathrooms.

Is the electrical installation assumed to be in good condition?

My gut reaction is to say that the person in the bath is unlikely to receive any sort of electric shock, both the live and neutral of the hairdryer will be submerged in the water and I would expect the majority of current to flow from one to the other. I suspect that the person would be at more risk of a shock if they were to touch the metal taps (if the are bonded) or possibly if they were to get out of the bath and put one foot on the floor whilst the other is in the bath they may receive a shock.

I also doubt that enough current will flow to operate a circuit breaker, depending on what chemicals are in the water. An RCD will likely operate if there is any path to earth for current to flow.

Thanks for your quick answers! I'm researching a story, so for the sake of fiction we could assume that it's an RCD, that the hairdryer is plugged into an extension cable running from a nearby bedroom (it's a suicide situation), and we could assume that (as the shock is intentional) the character knows that he/she needs to touch the tap with his/her toe to complete the circuit. Would this be likely to cause electrocution? Thanks again for your help.

 

[telectrix]

he/she needs to touch the tap with his/her toe to complete the circuit. Would this be likely to cause electrocution?

Probably. But dependent on the reliability of the RCD (should trip <30mA or 0.03A). could just be a painfull jolt.

 

[littlespark]

If this is for a work of fiction, let her be killed by a dragon or something.

 

[telectrix]

If this is for a work of fiction, let her be killed by a dragon or something.

she is the dragon

 

[littlespark]

she is the dragon

Great. I don’t need to buy the book now. Way to go ruin the ending!

 

[DPG]

Thanks for your quick answers! I'm researching a story, so for the sake of fiction we could assume that it's an RCD, that the hairdryer is plugged into an extension cable running from a nearby bedroom (it's a suicide situation), and we could assume that (as the shock is intentional) the character knows that he/she needs to touch the tap with his/her toe to complete the circuit. Would this be likely to cause electrocution? Thanks again for your help.

Seems a bit unlikely that they would know that, unless they have some electrical background. And if they did then why not just hold a neutral wire in one hand and then grab a live with the other. On a non-RCD protected circuit obviously.