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Thread: Ongoing problem with flickering lights

  1. #11
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    Hi Tunes

    Your voltage is definitely an issue as your voltage should be close to 230 volts on average not 215 volts. I worked for Eskom and whenever we installed transformers we had to ensure the voltage was as close as 230 as possible generally between 228 and 236.

    If your voltage is low then your dimmer lowers it even more your lights will battle to function.

    I read that when the counsel stepped up your voltage it helped with the lights that in itself is an indication of the issue.

  2. #12
    Diamond Member AndyD's Avatar
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    When you say they flicker, is the flickering quite subtle or are the lights almost flashing?

    I don't see the logic that would take you from a flickering lights issue to a 3-phase upgrade.... but if you had a 3-phase upgrade I guess your supply cable would have been replaced and reterminated entirely which should rule out any problems caused by poor terminations. Also if your electrician performed the usual tests he'd have noticed any floating neutral problems.

    Low voltage wouldn't cause halogen lights to flicker, it would just make them a bit less bright. Low voltage could however cause dimmers and LED lamps to become unstable and flicker. This kinda fits with your symptoms so I wouldn't rule out low voltage as a possible cause. I've also see cases where one dimmer on a circuit was unstable and the inrush current every time it flashed caused sufficient voltage disturbance on the circuit to cause other dimmers to also flash.

    The problem you have now is that mismatched or incompatible dimmers and LED lamps can also flicker so now you've installed LED's it adds another variable that could be compounding the original problem.

    From the info you've given I don't have any firm suspicions about what the cause may be. If it were me I'd start again from the beginning with a full inspection and test of the supply, the DB and the final circuits, this would rule out neutral problems and other obvious possibilities. If everything looked good I'd probably look at splitting your light circuits across 2 or 3 different phases which would illustrate whether the problem is just on one phase or on all phases. I'd probably also temporarily convert one room back to halogen and fit a known good dimmer just as a reference to highlight dimmer and LED incompatibility issues.
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    Quote Originally Posted by AndyD View Post
    When you say they flicker, is the flickering quite subtle or are the lights almost flashing?

    I don't see the logic that would take you from a flickering lights issue to a 3-phase upgrade.... but if you had a 3-phase upgrade I guess your supply cable would have been replaced and reterminated entirely which should rule out any problems caused by poor terminations. Also if your electrician performed the usual tests he'd have noticed any floating neutral problems.

    Low voltage wouldn't cause halogen lights to flicker, it would just make them a bit less bright. Low voltage could however cause dimmers and LED lamps to become unstable and flicker. This kinda fits with your symptoms so I wouldn't rule out low voltage as a possible cause. I've also see cases where one dimmer on a circuit was unstable and the inrush current every time it flashed caused sufficient voltage disturbance on the circuit to cause other dimmers to also flash.

    The problem you have now is that mismatched or incompatible dimmers and LED lamps can also flicker so now you've installed LED's it adds another variable that could be compounding the original problem.

    From the info you've given I don't have any firm suspicions about what the cause may be. If it were me I'd start again from the beginning with a full inspection and test of the supply, the DB and the final circuits, this would rule out neutral problems and other obvious possibilities. If everything looked good I'd probably look at splitting your light circuits across 2 or 3 different phases which would illustrate whether the problem is just on one phase or on all phases. I'd probably also temporarily convert one room back to halogen and fit a known good dimmer just as a reference to highlight dimmer and LED incompatibility issues.
    Hi AndyD

    You're completely right regarding the three phase upgrade and it was perhaps unnecessary - but I wasn't clued up on this and thought it would accommodate if ever I have too much appliances running like underfloor heating etc which would require more power and at the time it felt it was the right thing to do. I also thought that it would balance the load coming in so that the lights would get a more stable power. Obviously if all three phases decrease significantly during peak hours, this would still cause my lights to flicker.

    The flickering is not subtle by any means - it's flashing periodically every 5 minutes - sometimes longer to have a pause of 5 minutes just to flash again for five minutes and so it carries on.

    Yes the supply cable and all was replaced as well, so again it leads me to think that it's the power fluctuations during peak times that seems to be causing this. I'm not ruling out any other issues but so far it seems to be pointing in that direction. I only notice this in the evenings and early mornings which again leads me to think its the power coming in.

    When you say low voltage wouldn't cause halogen lights to flicker - I must disagree with you there because when I initially bought the house, it only had halogen light bulbs - all with dimmers and one could clearly see the flashing (again during peak hours) Perhaps not as and as the LED's but definitely enough to have a disco party

    The new dimmable LED bulbs and trailing edge dimmers are the compatible ones I purchased straight from Eurolux. I have the GU10 7W dimmable LED bulbs with Trailing edge Shuttle dimmers which are the dimmers that Eurolux sells and recommends to be used. I can dim the LED all the way in the day and all seems good - no flashing. Even doing peak times, the 5 minutes it doesn't flash when completely dimmed but soon after it starts flashing like crazy.

    I agree that the LED adds another variable as you say because they are more prone to flashing or flickering but again, the halogen ones also flashed but not as bad, so in my mind whatever is causing this ins the same issue?

    I'll do another test of supply with a log tester but I'm almost convinced that it's a power drop in the phases coming in especially doing peak times (I found that in summer the flashing wasn't as bad and as often)

    What would one need to do for CityPower to rectify this problem. They once tapped the transformer and it seemed to sort out the problem but I'm assuming that they've worked on the transformer since or substation and tapped the transformer back down again - It was apparently on setting 2 and they tapped it to setting 3. I'm guessing it back on 2. Maybe the transformer is also old and CityPower doesn't care enough to replace it and if they don't replace it and only tap it up again, then the who says it's going to stay at the higher setting in future?

    Thank again for your input - it's greatly appreciated

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    I would stick to Andy's orginal suggestion - Take out the dimmer switch and switch str on and see what transpires.

    I am would also change one room to Osram/Phillips LED GU10 dim able and see what happens - Had to many problems with the other makes and refuse to use them

    Problem with them setting the tap up on the transformer to cover the evening problem is that the voltage will go to high during the day and do damage to equipment.
    You could also be at the end of the line .

    What happens if you leave off your underfloor heating , and any other heating equipment in the evening

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    Quote Originally Posted by GCE View Post
    I would stick to Andy's orginal suggestion - Take out the dimmer switch and switch str on and see what transpires.

    I am would also change one room to Osram/Phillips LED GU10 dim able and see what happens - Had to many problems with the other makes and refuse to use them

    Problem with them setting the tap up on the transformer to cover the evening problem is that the voltage will go to high during the day and do damage to equipment.
    You could also be at the end of the line .

    What happens if you leave off your underfloor heating , and any other heating equipment in the evening
    Hi GCE,

    I have done this already. I have taken out dimmers in certain rooms and the lights don't flash in that specific room anymore. Obviously with full brightness of the bulb the flashing is not as perceptible to the human eye as it has different hertz - same applies if I increase a room with dimmers to full power on the dimmer switch - the flashing decreases to almost non visible to the human eye)

    This then defeats the purpose of having dimmers completely?

    I would like to try out the Osram/Phillips GU10 LED as you suggest but already have purchased over 200 Eurolux LED dimmable bulbs, new Schneider push button dimmer buttons switches with all new Shuttle trailing edge dimmer switches in all the rooms of the house. I have also contacted Eurolux and Shuttle dimmers to enquire about the dimming but it if it's the dimmers, then why did my old original wire wound dimmer switches with normal halogen bulbs also flash? This tells me it can't be the dimmers or bulbs? I could be mistaken?

    Ive also tried to switch all appliances (including geyser and underfloor heating etc) off but lights still flash. This happens summer or winter (winter seems to be more often and the flashing is worse)

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    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?

  7. #17
    Diamond Member AndyD's Avatar
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    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.
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    Quote Originally Posted by AndyD View Post
    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..

  9. #19
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    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.

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    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.

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