You can have an earth stake with a PME supply - it just becomes another of the multiple earths.
(There was even a suggestion that the 18th edition might make it a requirement - but that was shelved when they thought through the impracticalities of that in a number of circumstances)
For some values of live. Its one of the reasons TN-C-S installs are so insistent on the need for maintaining an equipotential zone. The theory being that live water pipes etc are only a risk if you are able to touch them and something else that is at a true earth potential. If everything you can touch is at much the same potential (even if that is 240V adrift from true earth) there is no shock risk.
Yup, ABCs are more robust in general, and its also much harder to snap just one of the conductors.
Yup, that's a good point actually - We have a pole mounted transformer feeding a dozen or so properties. Must admit I have never studied the earthing closely. They replaced our 4 line street wiring a couple of years ago with ABC.
A simple earth stake can't do any harm, but it is not necessarily going to make that much difference to the potential reached during a neutral fault. Say the active loads on the supply beyond the fault add up to about 5kW, resistance 12 ohms. And the best likely stake gives 100 ohms earth resistance. Then it is only going to reduce the final voltage on the house earth by about ten percent.
They recently changed our single phase transformer, and used new ABC cables from the tansformer pole. But the two houses that have two wire overhead connections from a second pole got left untouched. We have a TN-C-S supply, but I don't know about the other four houses. Ours and a newly supplied building have underground connections to a nearby pole supply which I suppose provided another earthing opportunity, but I don't know if they used it.
The top layer can dry out and shrink quite dramatically though. At the end of the summer can can dump 15,000l of swimming pool water on the lawn and it does not even leave a puddle!
Do you know many years ago now i used to work in a TV repair shop and we used the Philips monochromes chassis which were notorious for blowing mains dropper resistors the repair was to solder a large wire wound resistor across the open circuit sections. We use to wrap it round with pliers then solder it with a large instant heat gun, this was often just had its wires to where the mains came into the TV.
Back then the TV chassis was likely to be at live mains potential on the TV course back in two pin plug days and reversible connectors it was quite often the done thing to have the whole metal chassis live.
No one ever got a bad belt but a tingle plugging up the aerial sometimes;!..
Probably not a lethal shock but enough to be unpleasant.
I wouldn't trust my flagstone floor to be at anything other than local ground potential. And I have had a small shock from a telescope that had mains live leakage despite being up a wooden ladder at the time.
Careful examination of the poles shows that they are now PME even if all the houses round here all have a copper stake driven into the ground from the original TT install where there were four independent wires any one of which could be snapped independently (although usually it was the top wire that got snapped moving neutral toward the remaining phases).
It was particularly exciting in wet weather with the remains of the perished rubberised fabric hanging down and flapping in the breeze arcing and sparking as it touched other conductors.
Same here. We have a very high water table and an intermittent spring part way down the garden. I have to syphon water out of the pit before using it. There is a capped well only a few metres away.
The clay round here bakes to impermeable in a good summer which can mean a big thunderstorm runs off the fields towards a couple of unlucky houses. It doesn't happen very often but when it does the field drains simply cannot keep up and we get a fountain at the bottom of our drive.
Anybody who wires up mains leccy with toothpaste tube caps, and whose plugs are just modern versions of two nails hammered through a lump of wood, has no right to complain about other people's electrical systems. !
too funny. In fairness though, their domestic electrical fire rate is about the same per capita as ours. So it seems dognuts aren't as terrible as I thought.
Unless Statistics are gathered using the same criteria, comparison can lead to false ideas.
Of the 1,000 US Electrical deaths per year about 300 are lightning strikes, 400 are contact with high voltage power lines, and most of the rest are trade workers doing something wrong.
Several sites indicate the UK has more than a few electrical saftey concerns.
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Being a North American, I would have to use my passport to get somewhere with 110V as normal wiring ( a British shaver outlet comes to mind )
Its rare to have any deaths at all from lightening here. Deaths from contact with the HV network are also pretty rare (in years when one occurs it typically makes the news. e.g.
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However if your figures are correct that still leaves 300 or so deaths - more than ten times the number we would expect here, with a population only five times the size.
Indeed, no system is perfect. However you need to read the stats carefully. Many of the fires that are classed as "electrical" tend to include things where the fire started due to misuse of an appliance like an electric cooker - but there was no electrical fault - it was just the source of ignition.
Of those where there was an electrical fault, its often something like a fridge freezer or a tumble drier that was faulty and started a fire. (the cause of the fire in the Grenfell disaster)
(Our electrocution death rate of the 20 - 30 / year includes deaths from contact with fixed wiring (a handful a year) and also ones from (mis)users of appliances.
Having said that the death rate is far from the whole storey - we will have 100K plus hospital admissions per year for electrical injuries, and a few 1000 of those will be more serious.
(also worth noting that electricalsafetyfirst is branch of one of the electrical contracting trade associations - and they do have a habit of "bigging up" their stats at times, and lobbying for more regulation etc)
They have isolating transformers included, so you would be fine so long as you don't touch both poles at once!
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