Do you know the earthing arrangement, you say you cannot see what the earth is attached too so could it be a TT earth and the rod has resistance of around 23ohms
What about "granny chargers" on TN-C-S supplies, This could possibly pose a large shock risk. (iv pulled the pin out of the grenade)
But as reg 722.411.4.1 says any outlet which is likely to be used to charge a car cannot use a PME earth without other precautions
And as mentioned previously...
Are switch mode power supplies not causing RCDs to trip due to harmonic content, in particular 3rd harmonics and how they affect the sine wave causing apparent higher neutral current and therefor causing an imbalance in rcd coil, and in fact has nothing to do with leakage to earth
Thats why...
A few people on YouTube have some videos of them tearing down cheap usb chargers and the like
Alot of the cheaper ones have very poor seperation between mains input and low voltage output, and there have been quite a few reports of the seperation failing and mains voltage being present on the...
These systems only disconnect the supply if the L - N voltage is outside of range of 207v - 253v it is still very possible to have a PEN fault with a dangerous voltage present on all exposed metal work and these devices would be non the wiser, therefore they do not protection against PEN faults...
We only have a reliable solution if all 3 phases are present
the current signle phase options are not really a solution
I think the DNOs should implement PEN fault disconnection as they have access to all phases easily, but that would require more cost
If installing a car charger would it not have been easier to keep it TT, and then not have to worry about PEN fault protection, etc etc
I guess getting it converted to PME means you dont need to worry about the possibility of the TT system being connected to the PME earth via water pipes and...
Or check out earthingservices.com, they have an electrode which is a round disc they also have conductive concrete which can help increase surface area or make it possible to get an electrode in a tricky location
Surprising the hot tub specialist didnt think/aware of the relevance of the earthing arrangement used as its quite important for hot tubs.
The fact your electrican has fitted loads of hot tub on PME without issue doesnt mean the voltage drop on the PEN conductor is not the issue as this will...
Have you tried the button on the test lead, if it works with that test button on the probe/lead then it could be the switch/button on the unit at fault
Could bonding it present a risk which was not otherwise there due to it being a TN-C-S supply
Risk of metal frame voltage rise difference to the ground around it from a PEN conductor fault, or even tingles from normal PEN conductor volt drop
might be worth having a chat with www.earthingservices.com
They sell other alternatives to earth rods, for use in almost any location, including conductive concrete or foam which will shape around any rocks and give good surface area contact.
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