I have been in my 1930's semi for over a year and since moving in I have noticed that on any lighting circuit in the house (on different fuseways), the lights seem to momentarily either dim or flicker maybe once or twice during the evening.
I have since installed a new radial lamp circuit in the living room (on a spare fuseway in the fusebox) and this is affected in the same way.
Other electrical applicances (tv, stereo etc..) appear unaffected.
Since the ligthing circuits are all on separate circuits and fuseways I can only deduce that it is the electrical supply coming into the house and so there will be nothing I can do about it?
Do you live in a rural location? Do you know, does your electricity supply come from a predominantly overhead distribution system? Do you know if any neighbours have noticed the same sort of flickering?
It could be two or three possibilities. A loose connection on the distribution system (usually overheads), a water or sewage pumping station nearby, even a car-mad neighbour using a plug-in welder.
Report it to your local electricity company. It'll help if you can come up with some time info over a couple of weeks.
What sort of area do you live in (city centre, rural, etc). Do you know how your electricity is delivered (e.g. 1/2 mile of poles coming over the hill?) Do neighbours have same issue? Can you associate the dimming with any other appliance you have, such as a heater cycling on and off? If you do switch on a large load (2kW heater, electric kettle, electric shower, immersion heater, etc), does the same thing happen?
Filamant lamps do amplify the effect of voltage variations as larger changes in light output. Switching to energy saving compact fluorescents would likely stop you from noticing the issue.
Im on the South West Coast but not rural. The electricity is underground, TN-S to a Wylex fuse box with cartridge fuses. I dont know how far the electricity supply (SW Electric) is from me.
There isnt any heating cycling at the time the lights appear to flicker and we are sitting watching the TV usually when we notice and not switching anything else on or off at the time.
It doesnt happen at the same time every evening but does not seem to happen until after 9.30 pm.
Yes, it's relatively straightforward. You basically use your incoming supply to feed a large UPS setup, which is itself capable to supplying your household needs. This effectively decouples your system from the incoming feed.
Let's say your maximum requirement is 80A at 240V, or around 20kW. You need to size your UPS appropriately - one of these should be fine:
If it really bothers you, you could put a UPS on your lighting circuit! However, if you use standard lightbulbs you'll either need a big (i.e. expensive) one, or to change all your lightbulbs to low energy types so that you could use a cheap one.
P.S. With, say, 10 x 20W CFLs on the circuit, even the cheapest models would have a stab at.
i.e. APC ES350, 350VA/225W. (~60GBP)
With 10 x 100W conventional, you need 1000W.
i.e.
APC Smart-UPS 1500VA/980W (~370GBP)
Will almost do it, if you swap one bulb for a 60W!
Alternatively, you might get away with a power conditioner, which is basically a UPS without a big battery. You get no downtime protection, but they might help with the flicker and maintain line voltage during a brownout. They'll also get you longer bulb life if you have habitual overvoltage on your line.
Low energy bulbs are much, much less sensitive to voltage change, so you only need to do one. Changing all the bulbs for quality CF is probably a good plan anyway, payback is relatively quick, unless you use electric heating.
their operation is not as dependant on mains v as filament bulbs. TVs usually use stabilised supplies, etc.
correct, if you mean about the momentary v dip. If its the visual effect you dont like, to be honest the only sensible advice forget about it.
These occur when heavy loads switch on - not so much heating loads, but high inrush loads, such as large motors, devices with largish capacitors like fl light banks, big halogen bulbs, large transformers, anything else that takes a heavy inrush current at switch on.
They also tend to happe a lot before power cuts, so if its going on for an hour you know what may come next.
The vast majority of UPSs do not decouple your "system from the incoming feed". There are 3 common types of UPS technology.
Standby type (EG. APC Back-UPS) pass the mains through via relays when the supply is in the range of approx 210Vac to 255Vac. Outside this range they go to batteries.
Line Interactive type (EG. APC Smart UPS) have a step up / step down transformer. So they pass the mains through via relays when the supply is in the range of approx 210Vac to 255Vac. If the supply is approx
170Vac to 210Vac they step up via the transformer and approx between 255Vac to 275Vac they step down. Outside this range they go to batteries.
True Online Double Conversion (EG. Powerware series 9) continually convert the AC mains supply to smoothed DC then construct a perfect AC output. These effectively decouple your "system from the incoming feed".
The first two types do allow the mains voltage to vary considerably so you will see the lights flicker just as much. If your mains supply hovers around either the lower or upper voltage then the line interactive UPS can make your lights flicker even more as it keeps switching between passing the mains straight through and either stepping up (or stepping down) the voltage. When it steps up or down the is a big jump in the voltage. Mains (line) conditioners typically work in the same way with a step up / step down transformer.
But true online UPSs keep the output voltage at a set 240Vac. They also output a totally clean sine wave. Whereas the first two types will pass through harmonics, distortion and some noise.
For lighting use a true online UPS.
As you might guess I run my own UPS business. Regards Andy
It's a very bad idea to run a UPS at or near full load. It will shorten the life time of the electronics. And if the load increases slightly the UPS will switch off due to overload. Also most UPSs won't help with light flicker (except true online double conversion) - see my earlier post in this thread. Andy
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