Advice ref blinking lights all circuits

[ipf]

, it's not an ideal method to use a cable that has been redundant to solve a problem that should have been sorted earlier, I would go as far as saying it's a rough solution, but without seeing the install it's maybe jumping the gun.

I don't necessarily agree there, Pete. If they've tested the cable and it's in decent nick, it could well have saved a lot of trouble both for them and Luke. It's not a full rewire, after all. Maybe they should have taken into account the shared neutral, but they obviously got to the bottom of that problem, quite easily. As you say, it's easy to assume without seeing. They seem a decent crew.

 

[FatAlan]

I’m far from being an expert but logically if you’ve had the CU replaced on a system that was ok before and have a flicker on two seperate circuits it suggests the fault is upstream from the MCB’s. As others have suggested ... loose connections to mainswitch, tails etc. Presumably there’s some RCDs in there as well?

 

[Octopus]

^^ good input .............. seem loose connections on the DNO head do this ..............

 

[Rpa07]

I would normally say that it may be a supply fault on one of the phases. Same thing happened in my house with blinking lights.
I didn’t ask around the neighbours to see if the same was happening next door or 2 down or 3 down to correspond with the phase (although the OP could do this if not done already)
The supplier corrected a fault on the supply and has been good since.
The OP had the DNO out to data log so that would and should have picked up something supply side.
I’m with everyone else otherwise and root for something loose that needs a wiggle to check.
Hope you get sorted.

 

[DPG]

I'm going to stick my neck out and say an intermittent neutral joint in the cable under the pavement, where the house is tapped off the main feed.
I want a prize if I'm right though.

 

[shaun1]

One other thing - it's not really noticeable on LED candle bulbs, but is on spot lights (LED and halogen) and oldschool fillament / energy bulbs. Any idea why this would be?

Tungsten filament bulbs are very basic - the filament is connected between live and neutral and the light output is (kind-of) proportional to the voltage across it. So when there is a dip you will see a drop in brightness.

LED bulbs and most electronics are powered via electronic outputs, which can adjust themselves so they always give the same output for a wide range of input voltages right down to 100v (we are at 230v (which is usually 240) here in the uk). They also have capacitors which act like a battery to store current and smooth the output during voltage fluctuations.

With regards to safety, loose connections and high resistance connections create localised heating, which can then make the problem worse, and can eventually become a fire risk. Circuit breakers and RCDs may not operate in this situation as there is no overcurrent or imbalance.

There has just been an amendment to the regulations stipulating that consumer units in houses now have to be made from a non combustible material to contain faults such as this and to prevent fires.

Whilst I don't think you need to immediately panic if there's no obvious cause, I don't think waiting weeks is acceptable. If the flickering gets worse or more often, or you notice a burning or fishy smell (melting insulation) around the CU then it may be time to turn of and demand they come back immediately.

 

[PEG]

Back in the good old days,before LED's and low energy gubbins,a chandelier of 500w halogens,would have already pushed this fault,to an obvious head

 

[Deleted member 26818]

Had something similar once.
Turned out to be an ill fitting main fuse holder.
The sprung legs were corroded and had lost tension over the years. Also the screw terminals for all conductors at the head were loose.

 

[Pete E]

If the flicker affects table lamps plugged into socket outlets, maybe next time the fault occurs, switch off the lighting ccts via their MCB's and see if the flicker on the table lamp stops?

 

[telectrix]

when all else fails, call in: