100ma rcd and electric shocks (view this one - stupid forum)
- Thread starter xr4x4
- Start date
Sponsored Links
Yes, a shock of any current up to 100mA and the 100mA shock that trips the RCD could still be fatal.
You could get a 199mA shock if there was a pre-existing 99mA fault current due to a neutral to earth fault when you took the shock from the Live.
It's that 'common misconception' again
There's nothing about an RCD which limits the magnitude of a fault current (whether through a human being or anything else) - that is simply determined by Ohm's Law. All a 100mA RCD will achieve is to limit the duration of any fault/shock current of 100mA or more to an extent that (at least with a 30mA RCD) considerably reduces the risk of serious injury or death. However, with a 100mA RCD, teh degree of protection is much less, hence the risk of injury/death much more; 100 mA RCDs are not designed to protect human beings.
We should probably also add the usual caveat, that if one touches the live and neutral conductors, but is not in contact with earth, an RCD offers no protection at all.
Kind Regards, John.
Sponsored Links
An electric shock requires two ( or more ) points of contact on the body. So one is the water heater, what is the second one ?
If the second one is a metal simk of similar then fault may be at the sink and not at the water heater.
Use a true ground reference, the ground rod if it known to be good, and measure the voltage on the water heater where the shock is being felt. If it is below 50 volts then suspect the second point of contact and measure the voltage on that. But also investigate that 50 volts as that is not good.
It could be the floor is live due to a damaged cable and the water heater is at true ground potential ( Thermal insulation under floor can also insulate the floor from ground )
By whom?
Do the manufacturer's instructions specify a 30mA RCD?
Why doesn't the socket circuit have a 30mA RCD? That's been a requirement for at least 20 years.
How come whoever installed the water heater didn't pick up on that?
Is the socket circuit a ring final?
As this could literally be a matter of life and death the only place to start is to get someone in who knows how to find and fix the fault, and to get them in as a matter of great urgency.
In the interim, turn the thing off.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
