Electrical repair report

Just to add to the confusion, here's a power strip that does the three-lamp kind of test, and shuts all the outputs off if it doesn't pass (and the test is continuous, will shutdown on intermittent faults).

In the last house I had (that was 25 years ago), I had lived there a couple years before I found this one. In a closet, somebody had stapled through the Romex, shearing the safety ground from the panel, and tying the hot to the safety geround of the outlet! I'd been using it for years when I touched what was plugged into that outlet and some other piece of gear at the same time and got a hard jolt! It wasn't hard to fix, but I was amazed I'd been using it that long without discovering the problem.

Jon

Well, the outlet-style GFCI only knows what it can sense. As long as current on the two blade contacts is equal, it has no knowledge of what is going on on the earth ground pin. So, even if the installation has wired earth to hot (outside the GFCI) it won't know that. In most installations, Earth and Neutral are tied together, generally in the first panel at the power entry. So, electrically, swapping them isn't different.

In the UK and other 240 V countries, there generally is no neutral. Hot, hot and Earth. In the UK, they have this balanced 110 V system for construction sites, using US 120 V power tools. That also has no neutral, in the sense we use it in the US.

Jon

Jon Elson was thinking very hard :

I think you are WRONG

240 volt countries generaly distribute 4 wires, 3 hots and a neutral. Often only 1 hot and the neutral to each house unless the load needs more (Aircon etc). Mostly the neutral is tied to the GROUND at the building entry as well as back at the last transformer pole or cabinet. The 110 volts in the UK is supplied by site specific transformers and not part of the domestic distribution I believe.

--
John G Sydney.

** My comment was CLEALRY about an "RCD on the circuit" and not a plug in unit used on a miswired outlet - which will operate normally.

** That's big news to all the folk who live there. ** Not the norm at all.

Neutral tied to the ground at the supply entry or nearby is the norm.

** They use portable isolation transformers for that.

** But is the only example.

.... Phil

Phil Allison prodded the keyboard with:

You can say that again Phil.

True ! But the output centre tap is connected to ground so that there is a maximum of 55 volts or half the transformer output voltage with respect to ground .

--
Best Regards: 
                      Baron.

John G prodded the keyboard with:

100% Correct ! Three phase's are used. In my street one phase is fed to properties on one side of the street, a second phase to the other, and it seems that the street lighting is on the third one.

Though we have had open neutral failures several times and one transformer fire in the past few years.

--
Best Regards: 
                      Baron.

John G prodded the keyboard with:

** Street lighting uses very little power compared to adjacent houses and then only at night - so no way would a whole phase be dedicated to it.

Betya it gets distributed across all phases here and there like the premises.

... Phil

Phil Allison skrev:

Here in Denmark, back when every street had electric poles, there were

5 wires: Neutral at top, 3 phases, and the 5.th for street light.

But nowadays, almost every pole has disappeared in favour of cables in the ground. I guess it is easier when there is no rock around :-)

Leif

--
https://www.paradiss.dk 

Eller begge.

** Well, there has to be some way of turning streetlights on and off each day and using a dedicated circuit is the oldest method. More recently, remote control systems have been developed using RF signals or each lamp or group has an electronic light sensor.

... Phil

s or each lamp or group has an electronic light sensor.

I haven't paid attention to this in 50 years, but back when we were kids, w e'd watch the street department replace street lights with a bucket truck. When the installer was done, he'd take his hardhat off and cover the light sensor housing that sat on top of the fixture to test the light. Not sure if they're still using photo cells or some remote activation.

Phil Allison prodded the keyboard with:

Yes that is how its done locally with light sensors on each lamp post. Although the sodium lamps are now being changed for led ones. The new ones are very white and you can see a definite spot or circle of light on the ground now. The actual lamp head is quite a bit smaller in size too.

--
Best Regards: 
                      Baron.

I was a bit surprised driving through Germany to see tube fluorescents being used for most of the street lighting. They had very high energy costs, we were paying 27 cents/kWt-hr. I've been back 6 years, I don't know what they use now.