ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades What could be causing this blip?

Hi Jusme, To eleiminate the ring circuit wiring do a simple continuity test.
Disconnect the ring main at the distribution board and measure the resistance of the conductors L-L and N-N the readings obtained should be identical if all connections are sound. Any substantial difference will indicate a poor connection that could be contributing to your problem. That will at least save you searching at each outlet for dodgy connections.
Have you considered that the problem could be on the power co underground service cable. Have known older joints to give problems especially if there has been an alteration. They can arc across for some considerable time before giving up altogether. Had one not so long back where treee rootes had strangled a PME service cable against rubble and pipes in a trench, that was causing lights to flicker on a whole estate. It eventually capitulated and blew a hole in the cable and cleared the sub. Assume that as you have not posted lately that all is O.K. at the moment.
Good luck in your search

Just a quick update. No more flickering lights and no blips been noticed by the UPS for several days now, so I'm hoping the problem is (was) external and has gone away. I'm hoping to get the panel at least visually inspected soon though, just to be safe.

Plenty of things to try if it starts up again though, thanks for the advice.

Ian.

Hi we are having the same sort of thing here. Around 5 pm we get a regular pulsing effect a momentory dip happening several times in succession. It happened last winter too maybe its just that the supply transformer is just about at maximum load

If it is consistently at the same time, I would suspect a large load on a timer starting up. Are you on a dual rate system where the water heating cylinders and electric stoves are on a separately switched power source? If so, does the power switch on or off at 5 PM?

Where I went to college, we routinely saw transients at 7 AM when PF correction caps were switched on.

It mite be some large load switching on although this is a residential area with a few shops so I personaly think that its a stuck tap changer or just or maybe lumpy lectric

I've heard complaints about siginificant dips in one particular region of Austria at exactly 10 PM. They're fierce enough to confuse various electronics, e.g. EIB lighting controls and even set off alarms. It turned out that the power company switches the entire distribution to night rate (separate meter) at that time and that's what causes the brownout.

Thanks for all your reply on this I'm sure otd some sort of network switching that causes it. Although why it would happen 5 or 6 times in a row is a mystery. How many goes does it take to do a bit of switching