I've just seen this article in E&T highlighting the increased incidence of reported broken PEN's from 57 in 2003 to 474 in 2021. It seems they are becoming less of a rare event.
David
I've just seen this article in E&T highlighting the increased incidence of reported broken PEN's from 57 in 2003 to 474 in 2021. It seems they are becoming less of a rare event.
David
There are some conditions that the neutral earthing resistor does not guard against - and the grounding to terra firma of any one phase like that barn in the incident described above
Thinking about it, I reckon it could help even then - provided the chosen resistance was much larger than the source's electrode resistance - which shouldn't be too hard - given that DNOs work to max 20Ω anyway (often <1Ω).
e.g. with a resistance >200Ω and Rb < 20Ω you shouldn't see PE dragged more than 1/10th of Uo above true Earth, no matter how low the resistance of the fault to Earth.
- Andy.
I must admit I find the faults described a bit confusing I can understand that if the neutral is broken then the current goes back via customers earth we had that at a house on the estate I lived on everything metallic was at a decidedly painful voltage above earth the DNO came out and sorted a damaged neutral in the meter box the weird thing was the estate was only converted to PME maybe a year before. What's needed now I think is everytime an EV charger is installed is for the DNO to install a long length of copper pipe in a trench in the street bonded to that customers CNE terminal in the house they can afford it what do you think?
What's needed now I think is everytime an EV charger is installed is for the DNO to install a long length of copper pipe in a trench in the street bonded to that customers CNE terminal in the house they can afford it what do you think?
Come to think of it, when I put in the duct for my service cable, it wouldn't have been difficult to put in a 20 ft length of 15 mm copper pipe, or indeed some form of copper mat. Even better would have been to put something under the 500 sq ft of garage floor, or at the very least to have made a connection to the rebar.
When we wired my daughter-in-law's house, there was a 60 ft trench, let alone their garage floor, which were available.
Hindsight is a wonderful thing, but I think that Kelly Marie Angel makes a very good point.
What's needed now I think is everytime an EV charger is installed is for the DNO to install a long length of copper pipe in a trench in the street bonded to that customers CNE terminal in the house they can afford it what do you think?
Come to think of it, when I put in the duct for my service cable, it wouldn't have been difficult to put in a 20 ft length of 15 mm copper pipe, or indeed some form of copper mat. Even better would have been to put something under the 500 sq ft of garage floor, or at the very least to have made a connection to the rebar.
When we wired my daughter-in-law's house, there was a 60 ft trench, let alone their garage floor, which were available.
Hindsight is a wonderful thing, but I think that Kelly Marie Angel makes a very good point.
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