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mains swings

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New Member
There's something the matter with my home mains. All my electronic devices and appliances show it, for example my lamps blink alot and I hear the fan speed is reducing sometimes. How can I work it out? Are there any voltage protectors fitting into intry mains to the house?


Most Helpful Member
Do the voltage dips seem to coincide with any large power draw loads switching on? Air conditioners, electric heat, washer and dryer, electric water heater?

How old is your house and where are you located?
Have you ever been able to get an actual voltage reading during one of the power dips? If so how much lower was it than the normal voltage?


Check the Neutral Wire on the breaker box. Thighten the connectors on all terminals and breakers. If they have added new houses on your block the load might be too much for the pole transformer. If the Neutral wire is loose the loads won't Balance.

mvs sarma

Well-Known Member
at times we get a 1/4Hz phase shifting of 2 sine waves and this causes a sort of dancing swing on the illumination. Not a perfect sync of grid. any further deviation circuit breakers trip at Substations and the faulty generating station would have to be taken off the Grid.
Locally, the Loose connections on the 230V/110V service lines crossing across lanes and sub lanes, get murky as the 11KV/410 or 230 Transformer is away from the customers house. In such cases , the only way is to call the electrical service people and show the problem, and coolly suggest without hurting their (dirty) ego, that the so called jumpers from the transformer to the customer's premises be cleaned and refurbished. this technique helped many times for me. Now luckily i stay in multi story building with Built-in Transformer.

Of course our other friends have already dealt with overloaded transformers.

hv addict

New Member
If you live in a older house and there have been new houses added around you that share the same pole transformer then i can see you having this problem. Pole transformers are designed to run at around 25% past their nameplate rating in the 105* summer heat and if they tapped the new house wireing from that transformer and it's pushing it's rating then you will get some voltage drop when your neighbor's air conditioning goes on. One other possible cause would be although not nearly as likely is that the distribution PFC capacitors near your pole are not adequate and there is some difference between the phase of the voltage and current but that would be more like a constant sag of line voltage.

Nigel Goodwin

Super Moderator
Most Helpful Member
What do ou exactly mean of pole transformer?
A big transformer on a pole down the street, they are pretty common in America.

As you don't have your location filled in we don't where you are, but I would suspect that it's probably somewhere with a poor electrical infrastructure?.
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