Possible Electrical Problems

[bkkmadness]

Moved into a new condo recently, same size as my old place, use the same amount of appliances but the bill comes in at twice the price. My electricity rate is from the govt and I have check the bill and it says I am using twice as much power.

Now as first I thought that perhaps I have a fast running meter.

But I have also got two fans that were working fine before that are now starting very slowly and showing signs of problems. And this week my television has burned out.

So I am wondering could I be getting too much power coming to my appliances? Electrical surges that are causing the high bills and also damaging my electrical appliances?

Does anyone have any experience of this?

Is it a possible theory?

How can I get this checked?

I will be speaking to the condo management soon and could do with some more information to arm myself with, any help would be very much appreciated.

[elkangorito]

Moved into a new condo recently, same size as my old place, use the same amount of appliances but the bill comes in at twice the price. My electricity rate is from the govt and I have check the bill and it says I am using twice as much power.

Now as first I thought that perhaps I have a fast running meter.

But I have also got two fans that were working fine before that are now starting very slowly and showing signs of problems. And this week my television has burned out.

What do you mean by 'burnt out?

So I am wondering could I be getting too much power coming to my appliances? Electrical surges that are causing the high bills and also damaging my electrical appliances?

It could be a couple of things but it sounds like the supply voltage is a bit high. The single phase voltage here is 220v when measured against 'earth' or 'neutral'. Generally, acceptable voltage tolerances are +10%/-6% of the supply voltage. In this case, no lower than 207v & no higher than 242v.

What kind of meter do you have? Does it have a spinning disc in it or is it electronic?

Does anyone have any experience of this?

Is it a possible theory?

How can I get this checked?

I will be speaking to the condo management soon and could do with some more information to arm myself with, any help would be very much appreciated.

[fletchsmile]

I'm no expert on electricity, but a few ideas

1) A subject came up a couple of weeks ago at work. Apparently the electricity we receive is often more than we need to run the appliances we have, especially aircon. The reason this came up is we have just installed some machines that regulate this, and apparently reduce your bills. From what I understand, it's something to do with the voltage supplied being more than you need. Let's say your appliance runs off 220v. But, the power from the Thai grid is actually 240v. Your appliances over use the additional 20v. There are machines that ensure you get a filtered 220v instead of 240v and hence reduce your bill, or perhaos even 210v as I believe they can run on slightly lower. As I say I'm no expert but that seems to be the principle. I'm sure there are some sparky's on here might elaborate.

This diff implies to me the electricty supply is uneven. Which also suggests some areas may use more than others. I'm just speculating though. Could also be that your old place had these enegry saving machines installed, and new ones doesn't.

2) Old aircon machines that don't run as efficiently can also eat more electricity. Often people don't have them regularly serviced, so they lose efficiecy. Amazing what a good servicing can do for you in Thailand...

To be honest double sounds a lot though.

A couple of scams I've come across which could also explain:

3) I used to have an apartment on the end of a corridor. I worked out the maids were using it while I was at work. The reason I found out was that when I got home a) TV was always on a Thai channel when I turned it on. I used to watch cable TV with English. Tried turning off the TV and on, and it came on the channel it was on when switched off, so someone was changing. I also came home one day to find boling water in the kettle. It was unplugged. I realised when I plugged it in and it knocked off a couple of seconds later boiled!

4) People sometimes rewire onto your metre! As wires are often external, they can just connect to your box. Put another way someone connecting with a box that you thought is exclusively yours is not uncommon in Thailand. Someone also told me it is not just electricity boxes either...

Anyway soe food for thought...

Edited September 26, 2007 by fletchthai68

[elkangorito]

I have 3 more questions Mr Madness;

1. How old are the fans.

2. Is anybody else having these problems.

3. Do your lights appear to be operating correctly (brightness, fluctuations etc).

[GuestHouse]

Get yourself a tourch - wait until its dark then switch off the main power switch to your house (at your fuse box/circuit breaker box)

Take a look to see if any of your neighbours lights have gone off when you threw the breaker - If they did throw the breaker back on a see of the neighbour's lights come back on.

Then with the power switch in your house switched off - go check your electricity meter to see if the disc is still spinning.

I've seen two cases of neighbours 'tapping-in' to other people's supplies in Thailand.

[GuestHouse]

By my reckoning if the electical appliences are the same or about the same, then in order to get double the power consumption the voltage would have to be up around 300V

I wouldn't rule out such a high voltage, but I'd expect you to really notice as all your appliences would be burning out.

If the checks for 'electricity thieves' draw a blank I'd get a good meter to check the voltage, make sure the test leads are in good condition (no bare wires) and if you've never tested electrics before wear some dry rubber gloves.

[londonthai]

can be just broken meter.

if somebody is stiling your electricity than most probably only for their aircon and not the lights

[chownah]

An easier way to see if someone is stealing your electricity is to just turn everything off in your apartment and then go see if the wheel is still turning on your metre.

[elkangorito]

Mr Madness, I'm keen to know what's happening.

Did you;

i) solve the problem.

ii) move to another condo.

iii) decide not to worry about it.

iv) decide to not use electricity any more.

[lopburi3]

The OP has a big "banned" as his membership group.

[tjo o tjim]

The more likely scenario is that the voltage is low, and the meter is just measuring current. Find out what the voltage at your outlets is. For it to actually burn out appliances, the voltage would need to be about 75% of nominal, or 165V. You might see it at slightly higher voltages if they are used heavily, but anything over 200V is generally preferred. The basic dial meters are actually pretty reliable and accurate, since they track actual kW consumption not just current.

Lower voltage requires higher current, but double the bill is a little odd.

[Crossy]

The more likely scenario is that the voltage is low, and the meter is just measuring current. Find out what the voltage at your outlets is. For it to actually burn out appliances, the voltage would need to be about 75% of nominal, or 165V. You might see it at slightly higher voltages if they are used heavily, but anything over 200V is generally preferred. The basic dial meters are actually pretty reliable and accurate, since they track actual kW consumption not just current.

This is the greatest degree of bull that I've heard for a while, a little knowledge is dangerous

Where do you get the idea that the meters just measure current?? Modern electronic meters measure Watt-Hours considerably more accurately than the old 'dial' type which tend to become inaccurate under low voltage, harmonic distortion or poor power-factor conditions (although IIRC they do tend to read low in these circumstances).

Until our OP serves out his ban (for whatever reason) and returns with more information we may as well stop speculating.

[elkangorito]

The more likely scenario is that the voltage is low, and the meter is just measuring current. Find out what the voltage at your outlets is. For it to actually burn out appliances, the voltage would need to be about 75% of nominal, or 165V. You might see it at slightly higher voltages if they are used heavily, but anything over 200V is generally preferred. The basic dial meters are actually pretty reliable and accurate, since they track actual kW consumption not just current.

This is the greatest degree of bull that I've heard for a while, a little knowledge is dangerous

Where do you get the idea that the meters just measure current?? Modern electronic meters measure Watt-Hours considerably more accurately than the old 'dial' type which tend to become inaccurate under low voltage, harmonic distortion or poor power-factor conditions (although IIRC they do tend to read low in these circumstances).

Until our OP serves out his ban (for whatever reason) and returns with more information we may as well stop speculating.

You beat me to it Crossy

[Naam]

The more likely scenario is that the voltage is low, and the meter is just measuring current. Find out what the voltage at your outlets is. For it to actually burn out appliances, the voltage would need to be about 75% of nominal, or 165V. You might see it at slightly higher voltages if they are used heavily, but anything over 200V is generally preferred. The basic dial meters are actually pretty reliable and accurate, since they track actual kW consumption not just current.

This is the greatest degree of bull that I've heard for a while, a little knowledge is dangerous

Where do you get the idea that the meters just measure current?? Modern electronic meters measure Watt-Hours considerably more accurately than the old 'dial' type which tend to become inaccurate under low voltage, harmonic distortion or poor power-factor conditions (although IIRC they do tend to read low in these circumstances).

Until our OP serves out his ban (for whatever reason) and returns with more information we may as well stop speculating.

to the best of my knowledge electric meters in Thailand have been changed to measure voltage metric and not imperial style, id est no more stones and pounds but kilograms. the ancient measurement of electric consumption (pounds per square inch) has been abolished since many years

[elkangorito]

Just to keep things going, I'll try to explain why I think that the OP's problem is related to high voltage.

i) Assuming the TV 'burnt out' with a 'pop' or another such sound, this is conducive with a higher than acceptable applied voltage - typical of most electronic equipment subject to such conditions.

ii) He said his fans were running/starting slowly. Most fans (the typical type used in the home) are driven by a 'shaded pole' motor. After some time, the shaded pole (a large lump of copper buried in the aluminium stator) develops a high 'reluctance', which in turn reduces the field offset used to turn the rotor in the required direction. This affect is accelerated if high voltage is applied to the motor because there will be higher currents flowing through the shadings thus the shadings develop this reluctance quicker. Once the shadings have been affected, the fan will also run more slowly. Conversely, a lower applied voltage will also cause the fan to start & run more slowly but usually the speed difference is minimal.

I base my suggestions on the idea that electronic equipment is more likely to go bang if subject to higher voltages, not lower voltages.

I concur with what Crossy says about kWh meters except that most of the later model induction type are pretty much immune to power factor (with the old meters, you could make them spin backwards if you used a high current inductive load ie a welder - this can no longer happen with the later model meters).

[Crossy]

Just to keep things going, I'll try to explain why I think that the OP's problem is related to high voltage.

....

I base my suggestions on the idea that electronic equipment is more likely to go bang if subject to higher voltages, not lower voltages.

I'm tempted to agree here, does sound like over volt problems maybe related to a severe phase imbalance?

That said, severe under-voltage can cause problems with inadequately designed (i.e. down to a price) switching PSUs. They continue trying to maintain their output by increasing the duty-cycle of the (usually single-ended) driver until either the transformer saturates (leading to uncontrolled current flow and a nice bang) or the transistor fails due to over-dissipation.

Last time I did any study of mechanical kWh meters was at Uni. a good few centuries ago, and the kit we had then was already old. Beautifully made Bakelite meters in polished wooden boxes, they made an 'interesting' smell when we overloaded them (as we invaribly did) and yes, we made them go backwards, although we used an over-excited synchronous motor to achieve this, these present a highly capacitive load (leading PF). Once upon a time they were actually used for varible PF correction, in this application they were called 'rotating' or 'synchronous' condensers (condenser is the old name for capacitors). http://en.wikipedia.org/wiki/Synchronous_condenser

Things have come a long way since then

Edited September 29, 2007 by Crossy

[elkangorito]

That said, severe under-voltage can cause problems with inadequately designed (i.e. down to a price) switching PSUs. They continue trying to maintain their output by increasing the duty-cycle of the (usually single-ended) driver until either the transformer saturates (leading to uncontrolled current flow and a nice bang) or the transistor fails due to over-dissipation.

I never thought of that

Last time I did any study of mechanical kWh meters was at Uni. a good few centuries ago, and the kit we had then was already old. Beautifully made Bakelite meters in polished wooden boxes, they made an 'interesting' smell when we overloaded them (as we invaribly did) and yes, we made them go backwards, although we used an over-excited synchronous motor to achieve this, these present a highly capacitive load (leading PF). Once upon a time they were actually used for varible PF correction, in this application they were called 'rotating' or 'synchronous' condensers (condenser is the old name for capacitors). http://en.wikipedia.org/wiki/Synchronous_condenser

Things have come a long way since then

I often wondered why my old man used to weld 'nothing' for hours on end. I found out later that he was keeping the electric bill down

And believe it or not, there are some industries that still use synchronous machines for PF correction...I believe that Comalco in Sydney used to use one but that was a while ago.

[Crossy]

And believe it or not, there are some industries that still use synchronous machines for PF correction...I believe that Comalco in Sydney used to use one but that was a while ago.

Yeah, I actually read the Wiki (after posting it), seems rotating capacitors are making a comeback as they provide stepless adjustment and are not affected by harmonics (which can cause overheating and failure of regular PF capacitors). The also provide significant flywheel effect which can bridge over brownouts.

[tjo o tjim]

This is the greatest degree of bull that I've heard for a while, a little knowledge is dangerous

Actually, I'm quite well aware how a real electrical meter works. The OP lives in a condo. IF he doesn't have an MEA/PEA service and is sub-metered by the landlord, then there is no guarantee he has a real meter. My assumption was that the condo used one of the cheap knock-off E-Mon/D-Mon meters that have voltage setpoints and just record current and multiply be the voltage setpoint. I actually had a project submitting on a similar meter to my amazement (in the US).

As for inverse-impedance devices causing a problem, that is much less likely since real power remains constant. Other explanations such as power factor are equally unlikely, since few people would install a meter that can record it, and a house just doesn't have that much reactive load unless something is badly wrong-- you would need significant slip on the motors to get total PF below 0.85, which is just odd for a modern home.

Get off the high horse. The only real valuable suggestion on the thread for anybody but an engineer is to shut off your power and see if the disk is still spinning.

[Crossy]

This is the greatest degree of bull that I've heard for a while, a little knowledge is dangerous

My assumption was that the condo used one of the cheap knock-off E-Mon/D-Mon meters that have voltage setpoints and just record current and multiply be the voltage setpoint. I actually had a project submitting on a similar meter to my amazement (in the US).

Get off the high horse. The only real valuable suggestion on the thread for anybody but an engineer is to shut off your power and see if the disk is still spinning.

So, why didn't you say that in your original post?

As to turning off the power and checking if the disk is still spinning, why would I repeat the (very good) advice although it still doesn't address the OPs problem of equipment going pop.

Edited September 30, 2007 by Crossy

[elkangorito]

Actually, I'm quite well aware how a real electrical meter works. The OP lives in a condo. IF he doesn't have an MEA/PEA service and is sub-metered by the landlord, then there is no guarantee he has a real meter. My assumption was that the condo used one of the cheap knock-off E-Mon/D-Mon meters that have voltage setpoints and just record current and multiply be the voltage setpoint. I actually had a project submitting on a similar meter to my amazement (in the US).

Now that you have explained yourself, I think the possibility of an E-Mon meter being used in this instance, is very slim as the E-Mon corporation don't seem to make single phase 2 wire 220 volt meters (or 4 wire 3 phase 380v). This is not to say that another brand of sub-metering is not being used.

It appears that the E-Mon meter is capable of maintaining accuracy to ANSI C12.1 & C12.16 (C12.16 has been superceded by C12.20). The specs indicate a continuous +/-25% tolerance of its' rated voltage. If this device was available for this application (220v single phase), it could maintain its' accuracy between 165 & 275 volts.

From the limited info the OP posted, I don't think it's a metering problem or electricity theft.

[sanuk12345]

Moved into a new condo recently, same size as my old place, use the same amount of appliances but the bill comes in at twice the price. My electricity rate is from the govt and I have check the bill and it says I am using twice as much power.

Now as first I thought that perhaps I have a fast running meter.

But I have also got two fans that were working fine before that are now starting very slowly and showing signs of problems. And this week my television has burned out.

So I am wondering could I be getting too much power coming to my appliances? Electrical surges that are causing the high bills and also damaging my electrical appliances?

Does anyone have any experience of this?

Is it a possible theory?

How can I get this checked?

I will be speaking to the condo management soon and could do with some more information to arm myself with, any help would be very much appreciated.

If you suspect that your meter is running fast, aside from checking whether someone else is tapping power off your incoming circuit, you might also want to check when your meter was last calibrated. If it is a primary meter, check whether they had applied the proper CT ratio. As for your appliances burning out prematurely and fans starting slowly, you might want to have an electrical engineer do a power quality test on your incoming service to determine what causes these types of power surges or sags.

[elkangorito]

If you suspect that your meter is running fast, aside from checking whether someone else is tapping power off your incoming circuit, you might also want to check when your meter was last calibrated. If it is a primary meter, check whether they had applied the proper CT ratio. As for your appliances burning out prematurely and fans starting slowly, you might want to have an electrical engineer do a power quality test on your incoming service to determine what causes these types of power surges or sags.

kWh meters for domestic use are not calibrated. They either work properly or they don't, at which point, they get replaced. They are cheap to buy.

Being a domestic supply & well below 100 Amps, CT's are not used.

As for the cause of the power surges, 'TIT'. Mind you, the power in the Dominican Republic is 1 000 times worse.

[Phrakhanong]

We get power supply problems even in Australia. In my neighbourhood, we seem to have an overly high voltage (my assumption) given the light bulbs need to be replaced a little too regularly. I query whether the OP has a problem with light bulbs. If not, it would suggest the problem is not voltage as I would have thought bulbs would be one of the more susceptible items to burn out.

[elkangorito]

We get power supply problems even in Australia. In my neighbourhood, we seem to have an overly high voltage (my assumption) given the light bulbs need to be replaced a little too regularly. I query whether the OP has a problem with light bulbs. If not, it would suggest the problem is not voltage as I would have thought bulbs would be one of the more susceptible items to burn out.

Having lived in Australia for nigh on 40 years, I can agree with you totally. Usually, the voltage problems in Australia are in densely populated areas where the supply authority has upgraded a sub transformer OR the area is underdeveloped (not many electricity users).

I had this situation once when I was the chief engineer of 2 hotels in Sydney CBD. One of the hotels , of which I was in charge, had just been constructed. The supply authority had upgraded the sub station underneath the hotel (they installed a larger transformer to handle the "future" load). Since the load on this transformer was small, the line voltage was quite high at 260v, which is still within acceptable limits. This, however, did hasten the death of many light globes throughout the new hotel (expected life about 2 years, actual life - 1 year).

As for the OP having a problem with lamps, we await his return from "holidays" before this question can be answered.