Strange Electrical Phenominom

[jayenram]

I have a single phase 30/100 A supply to my house via a 16 breaker consumer box. The lights and wall sockets are on separate breakers.

I recently bought a ‘home theatre’ system which is now fully installed. However, whenever I switch on a fluorescent light in the house, the sound from the receiver is lost during the starter operation, probably for ½ second. The peculiar thing is that this also occurs when the light is switched off.

Has anyone any ideas before I call the local electrician in?

[Crossy]

Has anyone any ideas before I call the local electrician in?

I seriously doubt that a Thai electrician will have a clue as to why you're having this difficulty

I wonder if your home theatre is protecting the speakers from 'orrible transients caused by your lights.

A couple of ideas:-

Try plugging in to a different outlet (use a long traily lead to experiment).

Do your lights have electronic ballasts? If not buy one and see if it fixes the problem for the one light.

If you have a UPS for your PC, try plugging the theatre into the UPS (as a test)

Have a word with the supplier, get on the makers website, maybe others have this problem.

Finally, the answer your electrician will give "don't turn the lights on and off whilst using the system".

[lopburi3]

The starter type florescent lights do cause electrical interference when that cap is discharging (lightning type effect) so if you have indoor antennas/unshielded antenna leads it may mute your receiver rather than provide the noise a cheaper unit might provide. Assume this does not happen when using a DVD/CD type source?

A fix (other than non use) could be outside antenna or perhaps new lights as Cossy mentioned.

[chownah]

Does this happen with every light in your house or only with certain ones?

[jayenram]

Has anyone any ideas before I call the local electrician in?

I seriously doubt that a Thai electrician will have a clue as to why you're having this difficulty

Did you detect a little sarcasm in my comment?

I wonder if your home theatre is protecting the speakers from 'orrible transients caused by your lights.

A couple of ideas:-

Try plugging in to a different outlet (use a long traily lead to experiment).

I've just tried that. Same problem.

Do your lights have electronic ballasts? If not buy one and see if it fixes the problem for the one light.

I'll see what I can find in the local electric retailers.

If you have a UPS for your PC, try plugging the theatre into the UPS (as a test)

I had thought of that before but hadn't yet experimented. I'll give it a go.

Have a word with the supplier, get on the makers website, maybe others have this problem.

The system was bought privately, second hand, so there isn't a 'supplier'. The website is particularly unhelpful.

Finally, the answer your electrician will give "don't turn the lights on and off whilst using the system".

Thanks for your help.

[jayenram]

The starter type florescent lights do cause electrical interference when that cap is discharging (lightning type effect) so if you have indoor antennas/unshielded antenna leads it may mute your receiver rather than provide the noise a cheaper unit might provide. Assume this does not happen when using a DVD/CD type source?

A fix (other than non use) could be outside antenna or perhaps new lights as Cossy mentioned.

Thanks for your response.

The A/V receiver is only used for playing DVD's and CD's. The lack of local receivable decent radio stations has not convinced me to even connect an antenna. We use UBC for radio.

[jayenram]

Does this happen with every light in your house or only with certain ones?

Every flourescent light in the house (6). Turning on/off the flourescent 'type' long life bulbs outside the house has no effect.

[Plus]

Finally, the answer your electrician will give "don't turn the lights on and off whilst using the system".

He's not kidding. When they installed an LCD TV in our house there was something seriously wrong with colors - black turned into cherry red, we first noticed it when testing DVDs. Installation guys called the support and fiddled with dvd settings for half an hour. The red spread onto shampoo commercials. That was a breaking point - we can't stand cherry red hair in shampoo commercials, it's completely unrealistic.

The support than told us that the location is wrong and that we should move the TV. Installation guys duly did, no effect. Than we were told that maybe home theater speakers interfered with LCD, I didn't believe it for a second but we tried, I turned the sound system off. Then the guy told us that the lights might cause the red color. Installation guys gave him all the details about the lighting fixtures in the room. Support offered to watch the TV with no lights, and no sound system on.

At that moment I told them to pack the thing and bring a new, working one. Pickup driver who watched the whole scene from the porch outside backed me up.

It turned out next day that they got the wrong set from the storage, the set that was supposed to be sent back to the factory.

I don't know who was that support guy, he wasn't in the store at all.

[lopburi3]

Does this happen with every light in your house or only with certain ones?

Every flourescent light in the house (6). Turning on/off the flourescent 'type' long life bulbs outside the house has no effect.

I would check that your lights are not sending IR enough to mess up the receiver by covering the IR port (cover receiver if you must) and see if that stops it.

[tracker]

Interesting... cannot help directly but describe strange things which i see a lot here with the tube lighting.

In most houses there is no grounding. At nite, when the tl's are off they always flikker softly. I always wondered why. It needs quite a potential voltage to illuminate a tube. Most likely all that wiring in the houses, which flow over those lowered ceilings catch a charge since they work as capacitors (two conductors with insulation in between).

Anyway, switching on those cheap tl's from here, I guess they will create a lot of RF which might interfere with your soundsystem.

My advice, dump the TL's, install those philips bulbs with 6 year garantee. Lower powerconsumption, same brightness

[jayenram]

Does this happen with every light in your house or only with certain ones?

Every flourescent light in the house (6). Turning on/off the flourescent 'type' long life bulbs outside the house has no effect.

I would check that your lights are not sending IR enough to mess up the receiver by covering the IR port (cover receiver if you must) and see if that stops it.

I've tried turning on/off the flourescents in the kitchen with the door to the lounge closed. Same problem, so I can't imagine it being infrared.

[jayenram]

Interesting... cannot help directly but describe strange things which i see a lot here with the tube lighting.

In most houses there is no grounding. At nite, when the tl's are off they always flikker softly. I always wondered why. It needs quite a potential voltage to illuminate a tube. Most likely all that wiring in the houses, which flow over those lowered ceilings catch a charge since they work as capacitors (two conductors with insulation in between).

Anyway, switching on those cheap tl's from here, I guess they will create a lot of RF which might interfere with your soundsystem.

My advice, dump the TL's, install those philips bulbs with 6 year garantee. Lower powerconsumption, same brightness

We have all the sockets grounded but not the light fittings. That is not to say that every electrical appliance is grounded, of course.

The flourescents are not the cheap 12 volt type. They are 220 volt and were definitely not cheap. I agree that it would be sensible to go for the long life bulbs but the fittings that we currently have are not capable of accommodating such bulbs, therefore new fittings would be required. It will be worth making enquiries about what is available up here in the stiX.

Cheers

[chownah]

jayenram,

do your lights flicker as described in tracker's post?

Chownah

[lopburi3]

I would try that UPS test Cossy suggested as should be quick and easy. Turn on and then pull UPS plug out so running on battery power and see if still have same problem when turn light on.

Also try just using UPS as it may be enough to filter line if the problem is electric.

[johng]

My AV Amp ( cheapie bought in Thailand ) used to lock up or turn the volume right down

when a flourescent light was switched on,I'm almost certain that it was the Infra red sensor.

I moved to a different building and haven't had the same trouble here its very strange.

[jayenram]

jayenram,

do your lights flicker as described in tracker's post?

Chownah

If they do, it's barely discernable.

[jayenram]

I would try that UPS test Cossy suggested as should be quick and easy. Turn on and then pull UPS plug out so running on battery power and see if still have same problem when turn light on.

Also try just using UPS as it may be enough to filter line if the problem is electric.

I thought that it would be quick and easy also. Until I realised than the output sockets from the UPS were IEEE and therefore do not mate up with the power leads fron the receiver. I'm going to nip down to my computer shop later and see if they have one of those 'anti-spike' devices which could possibly help. However, I can't remember seeing one for years.

[jayenram]

I've now discovered that turning the fans on and off also have the same effect on the receiver. Haven't found a 'spike preventor' either yet.

[geoffphuket]

This isn't answering the main question, but flickering FL tubes after they've been turned off, is almost certainly due to the two main input wires at the fuse box having been connected the wrong way around.

The wall light switch's then turn off the neutral connection instead of the live. A very dangerous hazard when you turn the power off at the box to do a job and discover that the wires are still live

I've had two houses wired in this way in Thailand

[Tywais]

I've now discovered that turning the fans on and off also have the same effect on the receiver. Haven't found a 'spike preventor' either yet.

Usually for the surge protector/spike arrestor to work properly you need a 3-wire grounded system. Do you have that at your house? Also, you still should connect to a UPS to determine if the noise is induced (AC line - most likely) or radiated (RF/EMI - less likely) noise before a solution can be determined. If AC line and you have 3-wire grounded system for your receiver you can buy an AC chassis EMI/RFI filter at an electrical supply house and wire it up yourself. Done this several places at the laboratory I work at on sensitive electronics and external transient noise was then blocked.

[Crossy]

Usually for the surge protector/spike arrestor to work properly you need a 3-wire grounded system. Do you have that at your house? Also, you still should connect to a UPS to determine if the noise is induced (AC line - most likely) or radiated (RF/EMI - less likely) noise before a solution can be determined. If AC line and you have 3-wire grounded system for your receiver you can buy an AC chassis EMI/RFI filter at an electrical supply house and wire it up yourself.

I'm with Tywais.

I suspect that a regular 'surge arrestor' will have zero effect even if you're properly grounded, they are really intended to kill damaging spikes (lightning induced), the spikes from your lighting / fans are unlikely to be large enough to trigger the protection devices.

The EMI/RFI filter is what you need (assuming hooking up the UPS solves the problem, they usually have them built in). These DEFINATELY need a ground to operate correctly (it's the EMI filter that causes 'tickles' from unearthed PC cases).

Keep us informed

[lopburi3]

I've now discovered that turning the fans on and off also have the same effect on the receiver. Haven't found a 'spike preventor' either yet.

Now it is starting to sound (or mute) to very low voltage. Is it worse in the evening (or when more lights/fans and such are in use around you)?

The 30/100 amp service sounds very exceptional for upcountry power supply - I only have 15/45 amp service for five bedroom home here in Bangkok. 5/15 amp is the normal service for home use without air conditioning. It is hard to believe turning on a light or fan would cause a voltage drop if you really have feed of this size (30/100). If you can find a multi meter a voltage reading would be interesting. If normally very low you may want to get another UPS to bring it up a bit for the audio unit.

[jayenram]

Now it is starting to sound (or mute) to very low voltage. Is it worse in the evening (or when more lights/fans and such are in use around you)?

It doesn't appear to make any difference. As I've said, it's only the switching on and off of the lights and fans that cause the muting. All the flourescents and all the fans in the house can be on and there is no effect on the receiver.

The 30/100 amp service sounds very exceptional for upcountry power supply - I only have 15/45 amp service for five bedroom home here in Bangkok. 5/15 amp is the normal service for home use without air conditioning. It is hard to believe turning on a light or fan would cause a voltage drop if you really have feed of this size (30/100). If you can find a multi meter a voltage reading would be interesting. If normally very low you may want to get another UPS to bring it up a bit for the audio unit.

I paid an extra Bht 6,000.00 to install the 30/100 A as a precautionary measure when we built the house. The house we were renting during construction had only 5/15 A and we were suffering when more than two appliances were turned on at the same time (Shower, kettle and washing machine). The armoured cable that brings it in cost me Bht 240.00/metre over 6 years ago.

Anyway, thanks again - a voltage meter it is.

[jayenram]

I've now discovered that turning the fans on and off also have the same effect on the receiver. Haven't found a 'spike preventor' either yet.

Usually for the surge protector/spike arrestor to work properly you need a 3-wire grounded system. Do you have that at your house? Also, you still should connect to a UPS to determine if the noise is induced (AC line - most likely) or radiated (RF/EMI - less likely) noise before a solution can be determined. If AC line and you have 3-wire grounded system for your receiver you can buy an AC chassis EMI/RFI filter at an electrical supply house and wire it up yourself. Done this several places at the laboratory I work at on sensitive electronics and external transient noise was then blocked.

I do have a twin and earth to all power sockets (20 x twin sockets).

I'm afraid you're starting to lose me on the EMI/RFI filter but I'll see what I can find in the local shops. I'm beginning to think that I may live with the problem (as it doesn't appear to be doing any permanent damage) until my mate comes over from England at the end of September - he's a qualified sparks.

Thanks again for all the advice.

[lopburi3]

We don't seem to have asked but does this unit use a grounded plug? If not a simple change to ground the case might make the difference. You could test that with just a wire attached to a case screw and inserted into ground - if that works I would have a 3 wire AC cord installed.

[Tywais]

We don't seem to have asked but does this unit use a grounded plug? If not a simple change to ground the case might make the difference. You could test that with just a wire attached to a case screw and inserted into ground - if that works I would have a 3 wire AC cord installed.

Good point - forgot to ask also. If the receiver is only two wire, try reversing the plug in the socket (if possible).

[jayenram]

Good idea. I didn't think of that. The receiver, albeit built in Japan, has no earth. I'll be onto that today.

Cheers again.

[jayenram]

I would try that UPS test Cossy suggested as should be quick and easy. Turn on and then pull UPS plug out so running on battery power and see if still have same problem when turn light on.

Also try just using UPS as it may be enough to filter line if the problem is electric.

I thought that it would be quick and easy also. Until I realised than the output sockets from the UPS were IEEE and therefore do not mate up with the power leads fron the receiver.

Obviously didn't have my brain in gear when I checked the UPS. Only the mains input is IEEE.

Anyway, this morning I tried the test. Connected up the UPS to all the components and to the mains. No difference, i.e. the muting still occurred when turning on/off flourescents and fans. Then disconnected the UPS from the mains and checked again. No difference.

Today I'm going to earth the receiver chassis and try again. It's a big j*b as the box will need to be pulled out away from the wall to allow access to the rear of the receiver. The box is very, very heavy.

[jayenram]

Receiver now earthed - no change.

Oh well.

[lopburi3]

Those two tests would seem to rule out the receiver. Do you perhaps have an active amp located in your speaker system by chance that might be able to mute (looks like you might from photo)?

If all equipment was not on the UPS test try that again. Then ground on everything (perhaps the preamp in the disc player is muting)?

If you tune FM on receiver do you still have the same problem? If not it would indicate receiver (and anything down stream) is not the problem. If it does still happen the problem must be after the receiver (which I assume only leaves the speakers and any amp they contain (or a large power amp if you have that).