Lights flickering

[SparkALot]

Hello folks,

I have an issue in my property - flickering lights.  These are lights on the lighting circuit, as well as lights (eg table lamps) on ring mains.  Frequency is about one dimming dip every second or so, but variable.  Often times, there is no noticeable flickering (maybe there's none). Other times it's quite intense - enough to trigger outdoor PIR-activated floods lights to permanently 'on'.  This has occured during spells of dry days as well as wet days. No recent electrical work undertaken.

Switched 'off' the ring mains at consumer unit - lighting circuit lights still flicker.  Switched off lighting circuit - table lamps still flicker.

Flickering of ceiling lights and table lamps is synchronous.

Had an electrician round to check it.  He suspected fault in wiring may be causing sparking.  He replaced the main switch in the CU.  Flickering continues.

FYI, over the years (decades), we've have a couple of home improvements - extension and loft conversion. Each time a separate CU.  So we have three - original plus two for new works.

Now, here's the puzzler.  ALL lights - on all three CUs - flicker synchronously.  If any two CUs are switched OFF, there flickering symptoms continue.  It's does not matter which CUs are offed, the one that's on continues to have the symptoms.

So my thoughts are :

- is the issue meter- related?  We still have old style meter with a ratating (4"?) horizontal disc and rolling numbers (like old style odometers in cars) .

- is the issue further upstream and related to incoming cables?

- could there be a general supply problem?

Any thoughts/suggestions welcome.

Cheers.

 

[Sharpend]

Have you had a new meter fitted per chance? 

 

[Evans Electric]

I would suspect , as Sharpie says above,    your meter or your network cut-out  having a loose connection .     After that it would be a connection  outside  in the  street .  

Is your cut-out hot by any chance , are there signs of black jointing compound  leaking from cut-out. ?  

You electrician would have ruled out any problems on your side of the metering  I assume. ? 

 

[Geoff1946]

Have you asked your neighbours?

If an electrician has checked your consumer unit(s) then you have a good case for calling the supply authority.

It could be an underground fault or even in your main fuse but both of those are not your responsibility.

 

[Murdoch]

Could you get the spark back and see if the incoming voltage is changing when measured between. L and N?

Seen that on a few occasions and a loose connection on the supply head or out in the street were to blame

 

[ProDave]

I would be interested in the supply loop impedance.

Also I would want to try measuring the incoming voltage on an analogue meter, I would probably blow the dust off my old Avo 8 for that.  If the incoming voltage is dipping, you would probably see it better as an analogue pointer twitching, than trying to see numbers on a digital display change.

 

[binky]

phone DNO and report a fault

 

[SparkALot]

Many thanks for the responses.

Sharpend - still old meter - maybe when property was built!

Evans E - none of the black bakelite boxes are warm/hot.  (The symptoms have stopped since two days ago, but I expected resumption soon based on past experience.)  No blackening to be seen.

Have asked immediate neighbour who thinks they don't have a problem - but I haven't visited to confirm.

Electrician did some testing around the meter board, and said he noticed some fluctuations.  Suggested I speak to neighbours before calling UKPN.  (He joked that someone in the vicinity might have a little funny-farm going, which might result in the inconsistent nature of the symptoms.)

I'll ask a few more neighbours and report the outcome.   Just waiting for the next strobe show.

Cheers all.

 

[Sharpend]

Did your electrician check tightness of meter tails? Both at CU and any isolator between meter and Cu and possibly at the meter itself? 

 

[Murdoch]

Electrician did some testing around the meter board, and said he noticed some fluctuations.  Suggested I speak to neighbours before calling UKPN. 

Of what?

 

[SparkALot]

I think he was referring to fluctuating readings on his oversized tester.

Don't know if connections/tails were tested for tightness as I wasn't always keeping an eye - I didn't want to appear too intrusive.

It seems very odd that there are whole days without issues, then they start up a a while, then stop.  All daily activity carries on as usual - washingmachine, fridge, freezer, dishwasher, elec over, microwave, ironing etc, but does not seem to affected whether the flickering.

FYI, there are a couple of multi-storey blocks going up presently about 1km away.  Don't know if this could put a strain on the network.

Thanks for your interest.

 

[Murdoch]

It seems very odd that there are whole days without issues, then they start up a a while, then stop.  All daily activity carries on as usual - washing machine, fridge, freezer, dishwasher, elec over, microwave, ironing etc, but does not seem to affected whether the flickering.

That in itself is an interesting observation. I think you should keep a diary of when you experience this and report it to your DNO ...........

 

[SparkALot]

A few days ago, we experienced frequent symptoms, not just flickering but actual power drops in the sense that the boiler/PC etc would restart.  Contacted DNO.  They were not aware of any issues.  Spoke to some neighbours; they had the same experience, so asked them to also contact DNO.  Couple of hours later, saw UK Power Networks vans near local substation.  Then, no power for about an hour.  When back on, normal symtom-free service had been resumed.  Asked engineer whether he had done something - he said that an old-style fuse was tripping(!) and replaced it.  Hopefully a long term fix.

Thank you to all contributors.

 

[Geoff1946]

Nice to hear an outcome. Thank you.

 

[SparkALot]

Hello again forumites!

On a perhaps related issue, my mains voltage is showing about 205v - using digital testmeter.  Fluctuates +-5 with appliances (eg oven, dryer etc).  But the reading use to be pretty much 240v.  Any thoughts on why it would drop so much welcome.  Also any thoughts on potential adverse consequenses of 205v.

Cheers.

 

[phil d]

DNO again, probably a cable issue, we had something similar a while back, feeders from substations are on a ring, usually with link boxes to allow a section to be removed if there's a fault. It could be there's a fault and the ring has been broken leaving two radial feeders, in our case volt drop was due to use being on the end of a very long radial.

 

[SparkALot]

Thanks Phil D.

I'll check with some neighbours to see if they also have similar voltages.