JohnRoberts said:
Some very old outlets in the US are not polarized (neutral lead fatter), and many even when polarized are two circuit lacking a safety ground.
We have earthed sockets and unearthed. Appliances with double insulation (class 2) have no earth pin and can be plugged in both types, appliances with an earth pin (class 1) cannot be plugged in non-earthed sockets
theoretically. In fact there are too many cheater plugs.
My house is old enough that it lacks safety grounds behind the walls
In France, you run the risk of not being covered by your insurance in case of fire or death by electrocution. When you sell a house, you need a certificate of conformity.
Earhed sockets are mandatory for rooms that use water (kitchen, bath, laundry...) and also for rooms that have tiled soil.
I assume you are talking about conduction path through the primary winding?
That's correct.
UL stipulates well insulated line and neutral wiring inside equipment chassis. This is the primary line of safety management advocated by UL, but as I shared outlets with safety ground are not universally available, while certainly all new builds have safety grounds as well as other newer safety technology.
That's probably the most signifiacnt difference between US and France (actually Germany too), where emphasis is put on safety earth. A piece of gear that relies on earth continuity for safety should not be used where no safety earth is available; period.
I advocate for and use GFCI (RCL) outlets myself (around water) as a practical safety device that does not rely upon safety grounds to protect humans.
We just don't have these GFCI receptacles here. There is at least one GFCI at the trunk for overall protection, plus one to the outlets and one to the oven/range, In my particular case, I have a total of 5.
I have written about this at length (not about Norway). Here is a web page I put up a couple years ago
http://www.johnhroberts.com/OD1.htm I actually designed an outlet tester that effectively detects reversed polarity, and more importantly detects reverse polarity bootleg ground, actually very dangerous when safety ground is energized. (I abandoned the outlet tester product as too expensive NRE for too little return from a low priced SKU)
I am familar with your thread here. That's fascinating reading, in the sense that it addresses an issue that exists only because of the incredible amount of laxism of certain persons and concerns.
Many homeowners, in old houses like mine when upgrading to modern 3 wire outlets are tempted to bootleg safety ground to the neutral (nominally 0V).
Did nobody tell them they play with fire?
In addition to GFCI/RCL another modern mains safety device AFCI (arc fault circuit interrupter) actually detects loose wire junctions. Loose wire junctions can heat up and have been indicated in multiple house fires.
That's interesting; I had never heard about them until today.
Still there is a debate about them, up to the point that the standardization process is stalled since 2014. The main concerns are:
Pertinence: is there enough proof that arcing is a significant cause of fire? The "demonstrations" I've seen on Youtube do not convince me; the state of disrepair of the examples presented is caricatural. However, even if the number of prevented fires is small, it is worth it.
Performance: it seems some testers have managed to fool the detector. An issue here is that, since they are not mandatory, there is not much research done on them. Only one manufacturer makes them.
