Ongoing problem with flickering lights

[tunes]

The transformer could potentially be tapped to 240V as you can see with my data logger that it went on average at times to 202V during summer.. This surely will affect my lights? I don't know what else I can do if CityPower doesn't tap up the transformer?

I know they told me before that the power demand in the area is high and the substation or transformer is hardly coping - so I'm concerned that this is how it will be and I'll continue to have a flashing lights for the rest of time? If everything else fails, would installing a Pure Sine inverter on my Db board for the lights sort to out? I wish I knew what to do - Citypower should be assisting?

[AndyD]

For the supply authority it's a juggling act. There may be other residences on the same LV branch network as you that are considerably closer to the transformer, if they change the tap on the transformer to give you 220 or 230 volts it could put the other closer residences above 240 volts so it's not something they'd do lightly without some serious considerations of the effects on the rest of the network.

What I said about halogen lamps not flashing because of low voltage was true. A halogen lamp is just a filament that glows white hot at the rated voltage. Unlike LED's, linear fluorescents and CFL's it doesn't start to flash if the voltage gets low, it simply glows less brightly. As long as there's no dimmer on the circuit the only way a halogen can flash or flicker is if the voltage is rapidly changing.

Were there ever any 12v downlights in the house or were they all 220v? Reason I ask is that trailing edge dimmers especially can give problems if there's any wire wound transformers left in circuit. The output waveform of the TE dimmer into the primary coil of a 12v wire wound transformer can resonate and cause high voltage back into the dimmer which will either cause it to shut down and restart (flash) or fail conmpletely as the components responsible for clamping the output voltage get swamped and destroyed. This often happens where a light was removed but the old transformer was left somewhere above the ceiling.

[tunes]

For the supply authority it's a juggling act. There may be other residences on the same LV branch network as you that are considerably closer to the transformer, if they change the tap on the transformer to give you 220 or 230 volts it could put the other closer residences above 240 volts so it's not something they'd do lightly without some serious considerations of the effects on the rest of the network.

What I said about halogen lamps not flashing because of low voltage was true. A halogen lamp is just a filament that glows white hot at the rated voltage. Unlike LED's, linear fluorescents and CFL's it doesn't start to flash if the voltage gets low, it simply glows less brightly. As long as there's no dimmer on the circuit the only way a halogen can flash or flicker is if the voltage is rapidly changing.

Were there ever any 12v downlights in the house or were they all 220v? Reason I ask is that trailing edge dimmers especially can give problems if there's any wire wound transformers left in circuit. The output waveform of the TE dimmer into the primary coil of a 12v wire wound transformer can resonate and cause high voltage back into the dimmer which will either cause it to shut down and restart (flash) or fail conmpletely as the components responsible for clamping the output voltage get swamped and destroyed. This often happens where a light was removed but the old transformer was left somewhere above the ceiling.

Thanks again AndyD

I hear what you're saying about tapping the transformer and it makes sense. CityPower has in the past when I originally complained tapped the transformer which seemed to do the trick. It pumped it up to setting three which then gave me just over 230V. As it currently is the power fluctuates to an average of 202 V which in my mind seems low and it would justify the transformer to be tapped up without disruptions to the rest? If it helps, I have had no issues with appliances being damaged so far and it seems the issues are just affecting the lights.

I also agree with you regarding the halogen lamps being a filament that glows at the rated voltage, but I can assure you that the halogen bulbs that were in the house with the old wire wound dimmers flashed just as much (perhaps not as much but definitely enough to have a disco as well - I can even send you video clips of this when I first moved into the house as well as clips from the current LED setup - it's almost identical)

I believe the transformer box (big brown steel box across the road) is the one supplying my house (I could be mistaken) but if that is the case then I should be the one of the houses getting the power increase first in line?

I do still have some 12V downlights in the kitchen and stairs but if memory serves me right, those 12V transformers are all electronic and not wire wound ones. I can have another look to clarify but i'm sure I dd this a few times and only found electronic 12V transformers that are then connected to the trailing edge dimmer switches. All ceiling lights have been 220V - the only 12V lights are the ones in the kitchen cupboards and false ceiling which all seem to have the electronic 12V transformers..

[ians]

I have had customers complain about flickering lights...a couple weeks later no power...loose connection on the neutral...it doesnt seem to be the case at your house...the neutral would have been fixed when the cable was replaced.

I have had customers complain about down lights flickering when dimmed...found the the dimmer supplied was not compatible with the lamps.

I have had customers complain that down lights flicker when switched off...i have found this to be a common problem with a certain brand...replaced the lamps problem solved...we did look into fitting caps...but as i indicated to the customers not worth the hassle.

I would do a live to neutral test....neutral to earth and live to earth test at various points around the house...which should have been done when the power was upgraded.

After checking the voltage and loop test if all is ok...I would remove all the LED lamps then start with at one room...fit and test.

I have had a lot of issues with clipsal dimmers...i stay far away from them...I have a customer who has shuttle dimmers (wouldnt be my first choice)...my first choice would be R&D dimmers...i very seldom have issue with this brand...however the brand of lamp also becomes an issue...i stay away from flash products...they are cheap but after a short period of time you will know why...you might get lucky on he odd occasion.

[SiyaM]

Morning Tunes
I believe if your problems were from the reticulation network you and all your neibours would be affected by it but in your case it seems your problem is only localised to your installation and your problem is genuine. I also noted from the thread that your problems are in direct proportion with load of which that suggest(If the problem is local) you might have some sort of hot connection to the incomer either from the point of supply or to the point of control or in between. You once mentioned that your Neutral is returning to the earth bar and that is strange.
I will suggest that you get your installation fully inspected and tested by a reputable electrician before you spend a fortune trying to cure harmonics and induction problems which might be symptoms because if thats the case your problems will keep on returning. A full test report should pin point your problems and their locations.

[tunes]

Hi Guys,

I have an update regarding my flashing lights. I had an engineer at my home that measured the current in both lights fixtures and wall sockets with several equipment including a digital real-time oscilloscope. He came to the conclusion that the flickering is caused by the ripple frequency the power utility sends out in the area. I also went and chatted to some street neighbours and many of them experience the same flashing. It seems the ripple frequency affects all dimmers which are sensitive and thus causing the lights to flicker. I was delighted to hear that the issues is not in my house as most of you already suspected. The question is how would I bypass or get council to assist me in this matter? I have no ripple relays in my home - I'm guessing the power utility still uses ripple signalling in the area which causes harmonics in our homes. Could anyone advise what I could do? The ripple comes through in all three phases. I glad we've found the cause but the question is how do we solve it?

[SeanM]

Hi Tunes

Thank you for the update, it is always a pleasure to hear the final outcome.I know you send that when the voltage was stepped up the lights did not flicker, so in effect the ripple goes away when the voltage is raised.

[tunes]

Hi SeamM

It seemed to go away, or at least it helped but I think they tapped it back down at some point and as some of you have said that increasing or tapping up of the transformer may cause the voltage to go too high (which was not the case - it only went up to 238V from 220V) . The ripple signalling from CityPower will still be there regardless, which is what is causing the harmonics in the network and to sensitive equipment like trailing edge dimmers.

Ive read about low pass filters etc to cancel out ripple signalling to your home but not sure if CityPower would assist me and how I would go about for them to sort this issues out? I've spent thousands on new electrical switches, new cabling, new three phase and cables, new plugs, new bulbs, new dimmers and all new plug sockets - all as suggested by CitiPower because they had always said that there is no issue on their side and it could only be in the house - yet after undergoing all these expenses to find out that their ripple signalling is the cause, its rather frustrating and disappointing! They could have at least told me that ripple signalling/frequency was the cause but either they were too incompetent to tell me or had no idea that this is the cause. Either way I'm not sure where to go from here and how CityPower will assist me to filter or avoid their ripple signalling?

[Justloadit]

Maybe install a isolating transformer for lights circuits only, this may act as a filter.

[AndyD]

Alternative to Justloadit's suggestion is fit a ferroresonant UPS just for the light circuits. It would possibly give better filtering and voltage stability with the added bonus of it being a pre-made unit off the shelf and it will give you some back-up time in the case of power fail. If you're already using LED's the load should be relatively low so you'd only need a small UPS. https://www.powerman.co.za/online.html

[tunes]

Alternative to Justloadit's suggestion is fit a ferroresonant UPS just for the light circuits. It would possibly give better filtering and voltage stability with the added bonus of it being a pre-made unit off the shelf and it will give you some back-up time in the case of power fail. If you're already using LED's the load should be relatively low so you'd only need a small UPS. https://www.powerman.co.za/online.html

Thanks guys - will revert back when I've found a solution that works. I'm first going to try to get CityPower to install ripple signal filters (i think they'll have to do multiple filters on all three phases depending on the noise) I'm assuming the filters are installed outside on my main feed box? I also think a pure sine UPS dedicated for the light circuit would do the trick.

[Andreviljoen]

Hi. Sounds very much like a ''floating neutral'' to me.

[SiyaM]

Morning Tunes
I am a bit confused here. My understanding tells me the ripple voltage exist on DC systems that originate from AC sytems.
We are are talking about the AC system single phase 230 Volts RMS thats what munic is supposed to supply you. The voltage can flactuate due to veriuos reasons such as: floating neutral which is an earth fault. Overloaded trfrs, overloaded Lv networks etc the list goes on
I have neverseen any frequency controlling divices that are are installed on Lv reticulation systems to enforce a pure sine wave. Eskom generate transmit and distribute 50Hz with no filtering in between.

Either way your problem needs to be investgated by the supplier.

[Ridge]

Flicker with Shuttle dimmer

Hi all,

I had similar problems with Shuttle LED dimmers. A hotel were we installed shuttle dimmers does a generator test every month. After every test some Shuttle dimmers went wrong and started flickering. Initially we thought it to be the generator output voltage or shape. However after the load shedding last month we notice the same problem.

Everytime we had to go back to setup some of them.
Now it turned out that the Shuttle dimmer tend to loose its memory settings after a power disruption which causing it to go haywire. In the end I had to replace all of them with Bikkel dimmers just to be safe. The Bikkel does not have this problem and are cheaper anyway.

What is disappointing is that they must be aware of this problem at Shuttle but I do not see any announcement made by them. To proper thing to do is to recall such product. Now it is up to us electricians to sort out their crab. If I knew beforehand I would have replaced them all the first time. Now I went back the fifth time to replace them all as you can not trust them and basically you sit on a timebomb going off after the next load shedding. After the load shedding other clients were I installed Shuttle dimmers complained about the same problem. I guess I have to face this problem till all are exchanged.