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Topic: BEGINNERS: What is GROUND ? (Read 6031 times) previous topic - next topic

PerryBebbington

#15
Nov 04, 2019, 09:12 am Last Edit: Nov 04, 2019, 06:13 pm by PerryBebbington
Quote
That is not correct. In one house I had the mains was on a spur along our row of houses. One day the neutral developed a fault and got disconnected. The result was that we experienced twice the mains voltage in our houses.

This caused lights to fail and also electronic items like the Hi-Fi amplifier which was being used as a baby monitor at the time.

We got twice the voltage because the return was then coming from one of the other phases. If the neutral had been connected to the ground this would not have happened.
To be clear, I didn't mean just any fault, I meant something like live on contact with a water pipe for example. Your experience with loss of neutral is what I'd expect in the circumstances. Maximum possible voltage would be phase to phase, so on a nominally 230VAC system 230 * 3^0.5 = 398VAC (or in my house more like 250VAC * 3^0.5 = 433VAC)

In the UK the method of earthing generally used now is TNCS, which is what I was describing. It used to be common practice to take an earth FROM the incoming lead water pipe. Now incoming water pipes are plastic an earth is taken TO the water and gas plumbing from the electricity supply company's earth terminal. I have no doubt that not all properties are wired this way, especially if they have not been upgraded recently.

lastchancename

Reply #1 has a decent graphic, but it may be a bit complex for beginners.
I'll have a go when I return home and see about cleaning up this thread in general.

There's a bit of vague misleading and irrelevant chaff as it's grown...
Experienced responders have a nose for laziness, (they were beginners once)... Sure, there are trolls, chest-beaters, and pretenders - but the help you'll get here is about as good as it gets - if you try to help youself!.

Davidjames3321

Thanks for this information. It is useful

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