Electrical issues at our house

[surinteacher2016]

We live in a huge 2 story free standing house maybe aged 10 to 20 yrs. There's a beast of an electrical system installed in the garage.

 

Tonight I was upstairs in the office with the air con and the fan on. I noticed the lights suddenly dimming and the fan moved to half speed. After 15 seconds it returned to normal and then it happened again several times.

 

Can someone with electrical knowledge take a look at the photos and advise what the problem is.

 

thanks

[metisdead]

Have moved this to the electrical forum for knowledgeable answers. 

[chickenslegs]

I think you will get some expert advice if you ask a mod to move your topic to the Electrical forum.

 

Regarding the dimming lights, etc. This happens occasionally in my house - usually when work is being carried out on the overhead cables (even km's away).

Edited September 4, 2017 by chickenslegs
just seen it has already been moved

[bankruatsteve]

Yah, light dimming, etc. is caused by loss of voltage.  This normally has nothing to do with your CU.  Loss of voltage can be from the source (PEA) or from somebody using a lot of power on your same transformer (like welding).  If your grid is on the edge, it could be you running the microwave, toaster, etc.  If it's just your house having the dimming versus the whole neighborhood, you might have a fault somewhere due to weather, ants, geckos, dust, etc.  If the dimming is just your house, try to narrow down the circuit by flipping breakers off when it happens.  

[jeab1980]

We get dimming quite often its down to the dact we are at the end of the system the closest house to us runs a mig and tig welder almost every day 8 to 5 and the house next to him has his rice milling machine cranked up during the day to.

Funny it really only affects the lights.  TV and aircon work fine. Luckily we dont need the lights on during the day anyway apart from when going to the loo. Got used to it over the years. Seems we are in for a respite as next door has got premises and is moving his work there (not that it bothered us he is 1k away). 

[Crossy]

Yup, voltage drop somewhere. If it's an ongoing problem you could use the voltmeter on your board to record just how bad / often it's happening.

 

Then contact PEA, who will likely do nothing (but it can't hurt to ask) before installing AVRs (Automatic Voltage Regulators) which will smooth out the bumps.

[jeab1980]

1 hour ago, Crossy said:

Yup, voltage drop somewhere. If it's an ongoing problem you could use the voltmeter on your board to record just how bad / often it's happening.

 

Then contact PEA, who will likely do nothing (but it can't hurt to ask) before installing AVRs (Automatic Voltage Regulators) which will smooth out the bumps.

Your right there crossy PEA just looked at us as though we were aliens. There answer which i had to openly laugh at was "you lucky you have Electric" Mrs took a hissy fit to this day i have no idead what she said spoke far to fast for my thai skills. Still i suppose he was right to an extent we have Electric.

[jacko45k]

Incoming voltage drop.....

It can sometimes be a phase drop out on the high voltage side.

 

Get it at the house sometimes, where I may have some items working fine, others running slow, as my voltage is down. Neighbours may have a mix of situations from no apparent problem to full loss of power as they are on different phases.

[Naam]

11 hours ago, surinteacher2016 said:

There's a beast of an electrical system installed in the garage.

[VocalNeal]

Happens in our soi, voltage up and down like a newly weds nightie.

[xylophone]

4 minutes ago, jacko45k said:

Incoming voltage drop.....

It can sometimes be a phase drop out on the high voltage side.

 

Get it at the house sometimes, where I may have some items working fine, others running slow, as my voltage is down. Neighbours may have a mix of situations from no apparent problem to full loss of power as they are on different phases.

Can be this and other things mentioned by posters................

 

It can also be a poor or loose connection on the incoming feed to your board or even outside on the pole. Following this line of thought, there could be the same thing happening on one of your circuit breakers.

 

Can usually be seen as the cable will overheat as will the connection in general.....have fixed several instances of this happening here. A visual check can often pinpoint the problem.

[thailand49]

My years here, I've noticed this myself but found it to be with the power system in your area.  I seen one side of the block having power and the other or next door not, I've seen some homes rooms are dark or lights are dimmer.  It is like a power surge or outrage?

You will find answers as noted but if possible have the system checked anyways.

[shaemus]

1 hour ago, xylophone said:

Can be this and other things mentioned by posters................

 

It can also be a poor or loose connection on the incoming feed to your board or even outside on the pole. Following this line of thought, there could be the same thing happening on one of your circuit breakers.

 

Can usually be seen as the cable will overheat as will the connection in general.....have fixed several instances of this happening here. A visual check can often pinpoint the problem.

 

Great Answer, it could be one of the many things mentioned. If it continues then i would Get an Electrician in  (or yourself if competent) to check the terminal tightness on the circuit breaker connections and the incoming cabling, and as far back as you/he can to the Point of Connection Safely. Whilst this is happening i would visually check the condition of the cabling insulation etc.

 

This could be just an anomaly. Tap change on transformer, large load starting up. the list is endless really. As i said if it continues then check all your incoming connections. 

 

 

[English Engineer]

Measure the voltage at the switchboard and then check if voltage changes if you switch off air con etc. I suspect problem is external to your house. You can then ask PEA to investigate providing information as to the voltage drop.

[tandor]

2 hours ago, VocalNeal said:

Happens in our soi, voltage up and down like a newly weds nightie.

..towel

[shaemus]

5 minutes ago, English Engineer said:

Measure the voltage at the switchboard and then check if voltage changes if you switch off air con etc. I suspect problem is external to your house. You can then ask PEA to investigate providing information as to the voltage drop.

It looks like there is a voltage indicator with a selector switch on a part of this installation, as well as an Ammeter. 

[Elkski]

I'm really surprised the pros did not tell you to look at your inside system more carefully.   You make it sound like the air-con and fan have to be on before you see these lights dim? Or is it just that you're never in this room during the day without the fan and air con on?  I'm so surprised the pros did not ask you what type of light dims? Incandescent, fluoresent? A incandescent light is going to visually show any voltage differences.   Whereas a computer and tv have voltage regulators inside. 

Your Aircon should be on its own CB.  Maybe fan and light are together?

Why do you say you have a electrical mess in the garage?   If it's from outside supply voltage changes all lights of this type in the house should fluctuate brightness??  What times are these light fluctuations?  Micro seconds long  spaced  how far apart?  Or a slow up and down change? Or matching the Aircon compressor cycling?  Or matching the Tig welder.  I would get your wife and his on the phone and have him well on command and stop. 

It could be you have to have a certain amperage draw in your house before you see this diming.  But this means having a fan and ac on another room but not in this bedroom Should still show this light diming. 

I worry anout a bad ceiling fan,. Or an overleaded circuit the light is on, or a loose connection in this circuit.   Can be dangerous.   A fan with a semi faulty speed switch may be causing this issue.  A loose wire connection can be causing this issue.   Both these last things can be fire hazards.

If this is your neighbor up the line causing this you should see fluctuations on your volt meter.  A video of this meter while you observe the dimming .  But you may have to have the selector switch in a certain position?  

What I'm saying is if it's your main supply fluctuations it may only show when you have a certain power draw.  But the light Should dim even if you have Aircon off and fan off in this room as long as you go turn on another fan and Aircon in a different part of the house.    I suspect the fan.     If only this light dims in the house.  Unless this room is the only dark one and so it shows. 

Edited September 5, 2017 by Elkski

[RichCor]

17 hours ago, surinteacher2016 said:

We live in a huge 2 story free standing house maybe aged 10 to 20 yrs. There's a beast of an electrical system installed in the garage.

 

Tonight I was upstairs in the office with the air con and the fan on. I noticed the lights suddenly dimming and the fan moved to half speed. After 15 seconds it returned to normal and then it happened again several times.

 

Can someone with electrical knowledge take a look at the photos and advise what the problem is.

 

thanks

 

The photos don't really help, at least in helping diagnose why your service is suffering brown-outs.

But the photos do provide information on your setup; such as, your house is on 3-phase power and protected by a Safety-Cut (brand) whole house Residual Current Detection (RCD) device.

 

3-phase means your house is most likely wired in three zones, each section wired to one of each of the 3 available incoming power lines (or 'phases'). So the question is, does the 'brown-out' occur throughout the house and every circuit, or only some circuits. As other's have already stated, the drop in voltage is most likely sourced on the Electrical Provider's side and nothing to do with you or your CU/Breaker Box.

 

The whole-house RCD device means there's a protection circuit in place that, hopefully, will prevent anyone being electrocuted if an electrical fault occurs or someone comes into direct contact with an energized wire.

 

I'd have you ask a few neighbors who are connected to the same service transformer if they remember experiencing similar power loss at the same you did. If any said "yes", then this would put the issue on the power service provider side.

 

Just to add, there was a thread running just recently where the OP stated they were experiencing power brown-outs. A poor photo of some cabinet wiring lead us to ask them to inspect the cable run back to the meter. They posted back a photo of a power meter with what looked like burnt/singed wiring in the overhead common wire belonging to the power provider. This lead to the OP calling the power service who replaced the power cables servicing the entire row of shop houses.

 

So, if the neighbors aren't experiencing the same outages as you, it might be a good idea to have a qualified electrician inspect all your wiring for loose or burnt connections -- or any indication that a lose connection, over-heating wire, or Live-Neutral short may be occurring -- and preventing electrical current normally from flowing across the wires.

 

On the PLUS SIDE, you have 3-phases available. If you are only experiencing brown-out condition on only one of the three electrical incoming phase lines then you might want to consider having an electrician swap critical circuits, like those powering electronics, or essential lighting, etc., over to a better working incoming phase.  Note: each of the three incoming service lines (phase lines) are identified by color on your breakers (showing the alternating RED, YELLOW, BLUE tape labels), and by the letters R, S, T on the selector switches controlling what the Voltage and Current meters are monitoring.   

[Antioc]

Just had house rewired and on final check, after preventing borrowed/stolen Neutrals and a host of other problems that we sorted out, he demonstrated the upstairs RCBO.  Air circuit, Hong Nam and Power points.  What about Light Circuit!!!.  Oh that's on the power circuit.  "No it's bloody not" I said quicker that an MCB could cut out.  Took him an extra hour or so before I was happy and brought out the beers to ensure he didn't go away swearing that he would never do another farang job.  The moral here is, good luck with an electrician.  Their mentality is locked into no Earth, two pin plugs, borrow Neutral, pick up live wire wherever you find one and never mind.  I also had a huge job trying to get the guy to use screw connectors when joining wire.  Just twist like this and bend end over - easy, then use tape.

About 2 hours after he left I put everything under load and waited.  The lights suddenly dimmed and flickered, just about gave up on Thai Tradesmen at that point, yes, this chap had a piece of paper.  However, it turned out to be a voltage drop which the whole street experienced, not a regular occurrence here but does happen from time to time.

Edited September 5, 2017 by Antioc

[xylophone]

5 minutes ago, Antioc said:

What about Light Circuit!!!.  Oh that's on the power circuit

They seem to do a lot of that here.....wiring in zones so the lights, outlets, whatever in one zone are on one circuit breaker or two.

 

And "borrowed neutrals"..............bain of my life when helping out a mate with some building maintenance and fault finding.

[RichCor]

4 hours ago, Antioc said:

About 2 hours after he left I put everything under load and waited.  The lights suddenly dimmed and flickered, just about gave up on Thai Tradesmen at that point, yes, this chap had a piece of paper.  However, it turned out to be a voltage drop which the whole street experienced, not a regular occurrence here but does happen from time to time.

 

Can see why you might have been a bit miffed when it started flickering, but surprised you didn't find something else to do very quickly after learning the voltage drop was street-wide and just happened to occur during your power load test  

 

Anyway, too funny.

[Elkski]

Yes I neglected the 3 phase aspect in my post.  Would a big tig welder use two phases?   I know they do here i  USA where we only have 120 v.  

Op, where is the last transformer?   

[Crossy]

4 minutes ago, Elkski said:

Would a big tig welder use two phases?

Probably not, portables are single-phase, industrial (less portable) 3-phase.

 

I agree that the apparent pattern is that of a Thai welder,  any house construction going on nearby?  Even our baby 150A welder pulls our (15/45 single-phase) supply from 230V down to around 200V when it's active.

[Naam]

4 hours ago, Crossy said:

4 hours ago, Elkski said:

Would a big tig welder use two phases?

Probably not, portables are single-phase, industrial (less portable) 3-phase.

Elkski is obviously referring to the U.S. electrical system where two phases each 110/120 the result is 220/240 (still called single phase) but which can't be used to power "our" single phase 220/240 gadgets even though it's electricity generated in the Land Of The Free 

[Elkski]

Most USA houses have 2 phases brought in.  Two hots and a neutral.  We run welders clothes dryers, hot tubs, oven/ stoves on 220 using 2 phases.  It actually measures 208 v across the phases.  All other stuff runs on 120 v single  phase.    Our breaker sizes are 15 &20 .  I feel this wattage is safer than Thailand on 220 15 a breakers.    

 

I took this picture at the queens palace on that mountain top by Chiang Rai.  The whole walkway lighting system was done this way.   

Edited September 6, 2017 by Elkski
Added typical picture of Thailand electrical wiring.

[Naam]

1 minute ago, Elkski said:

Most USA houses have 2 phases brought in.  Two hots and a neutral.  We run welders clothes dryers, hot tubs, oven/ stoves on 220 using 2 phases.  It actually measures 208 v across the phases.  All other stuff runs on 120 v single  phase.    Our breaker sizes are 15 &20 .  I feel this wattage is safer than Thailand on 220 15 a breakers.    

Elkski,

volts don't kill, amps kill. a 12 volt battery can kill. breaker sizes in this respect are totally irrelevant.

[Crossy]

1 minute ago, Naam said:

a 12 volt battery can kill

Particularly if it falls on your head

 

Obviously as a Brit I believe that our electrical system is the safest in the world, only slightly behind Germany. I understand that 220V (ish) is the highest voltage that can be "safely" used in domestic environment (no I don't have a scientific source). But there's no doubt that the higher voltage (and lower current) does allow smaller (cheaper) wiring for the same power transmitted than our friends from across the pond.

 

Anyway, we have what we have wherever we are, Thailand is 3-phase, 4-wire star (wye) nominally 220V P-N so that's what we discuss. No high-leg delta and the like, for flips sake, who came up with this?

 

 

[bankruatsteve]

42 minutes ago, Elkski said:

Most USA houses have 2 phases brought in.  Two hots and a neutral.  We run welders clothes dryers, hot tubs, oven/ stoves on 220 using 2 phases.  It actually measures 208 v across the phases.  All other stuff runs on 120 v single  phase.    Our breaker sizes are 15 &20 .  I feel this wattage is safer than Thailand on 220 15 a breakers.    

 

The US is predominantly single phase supply where the neutral is grounded at the mid-point of the transformer giving two splits of the single phase.  Between the "left hot" and neutral is 120v potential and between the "right hot" and neutral is also 120v.  Between the "left hot" and the "right hot" is 240v.  (Where nominal varies beteen 110v and 120v)  The "left" side and "right" side are always equally opposite.  IE: when the "left" side is +110v to neutral the "right" side will be -110v.  The US does have 3-phase but almost exclusively for large factories, apartment buildings, etc.

[Naam]

43 minutes ago, Crossy said:

Anyway, we have what we have wherever we are

...and it can be exciting. during my time in Saudi Arabia the houses were wired with 110 and 220V sockets which were not marked. the first task of moving into a home was to identify and mark with a felt pen "who is who?"

[Crossy]

1 minute ago, Naam said:

identify and mark with a felt pen "who is who?"

My place in Seoul in the mid '90s was like that, light bulbs too were mixed voltages, I just bought 220V lamps, the ones in the 110V holders lasted forever