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Electrical Wiring in the Home/Higher Than Rated Voltages In Electric Mains


QUESTION: This relates to a typical problem unionised power-utilities labour can cause for hapless consumers in the third world. I have a 4 wire, 3 phase (240V 50Hz) power connection to my residence. Of late, there's a mismatch in voltages (phase to neutral) in the three different phases as measured right at the input terminals of the energy meter. The phase to phase voltages are uniform. When measured against a ground terminal, the neutral shows a voltage between 40 to 3 V. Individual phases can record voltages as high as 280-290V, causing voltage stabilisers, wherever connected, to trip off or for appliances/lighting fixtures to get damaged. I suspect the fault lies in the distribution of the state utility, but rather than getting into a slanging match with that lot, is it possible to correct the voltage in the neutral line by earthing it through some grounding arrangement?

ANSWER: Sounds like a bad neutral connection
This could be anywhere between your service panel and the transformer

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QUESTION: Thank you for the reply. It is most certainly from the electric pole to the transformer of the utility, perhaps from the transformer onwards. It could be some internal fault with the transformer. But the query really is, is there some means to earth the voltage that develops in the neutral wire, some sort of cut in device that would detect a higher than a threshold limit of voltage in the overhead neutral and divert it into the ground?

Sorry, but it doesn't work like that.
The only alternative to getting the utility to fix their problem would be to install a transformer at your end which transformed only the three phase legs and had a secondary winding neutral which would eliminate the need for the utility neutral.  I don't know if they allow that there, but is not a project for any but the most highly skilled tradesman.
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Electrical Wiring in the Home

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Robert Wilber


Licensed Philadelphia electrician serving Delaware, Chester, Montgomery and Philadelphia County in Pennsylvania. I install and repair residential, commercial and industrial wiring and lighting. Troubleshooting and repair of problems that stump other people is my favorite. I am willing to help people figure out why things don`t work. I understand motor controls, transformers and machine wiring. I do not teach basics to novices or do free design work.


Experience in the area I have 44 years experience in residential, commercial and industrial electrical construction and repair, 480 volts and below. This is not to be confused with one week repeated two thousand times.

44 years experience in residential, commercial and industrial electrical construction and repair

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