Desperate - Need HELP !!! Issue with voltage fluctuation in Bangalore

[Thad E Ginathom]

The last time I poked around with our EB board I got the worst shock I have ever had. I wasn't even messing with anything electrical, I was fixing mesh around cable entry points to the cabinet to keep rats out. Because I wasn't (according to my level of conciousness) even touching the electric stuff I wasn't thinking about the precautions that I might have taken. Something was live that should not have been; live (I put the meter on it afterwards) with full 440v; I touched it with my head and felt like somebody had punched me hard.

I [still] consider myself competent, at DIY level, with household electrics, but I wasn't clever enough to take precautions when I thought there was no risk.

With respect (for life and limb even more than for persons), if one has to ask how, what, and why about electrical testing, it is an indicator that we should be getting someone else to do it.

But... let's learn the theory anyway. Apart from anything else, we can then try to make sure that what the "professionals" do is safe!

 

[rdksrk2013]

How the 'earthing' protect/cause the voltage spike ?

This voltage will be due to Neutral problems and not earth faults. Either it is the voltage drop due to single phase / imbalance current over the neutral or it is a disconnected neutral. I would consider (on a 400V/230V system) a drop of 10V to be on the limit. You must also remember that this voltage drop can actually INCREASE the voltage at your board!

As an example of this take a street where each house in sequence is fed from a different phase. House n 1 and 4 both have a full house of electrics, heating, cooking, etc. they will cause the Neutral to rise toward L1. Let's assume a voltage standard of 230V +5%-10% giving us 241V max 207V min. The supply authority would might put out the max voltage possible from it's transformer, where the neutral is grounded. If the loadings work out at max then those houses on L1 get 207 V. Thus we could have (34V/2) 17V dropped across line and neutral. So if houses 2 & 3 are only using electric for TV and lights and thus assumed negligible voltage drop, they will receive not 230 V but, in this instance 242.5V i.e. outside spec! This is an extreme example and would never normally be this bad.

Now use the same scenario and look what happens if, at the bottom of the street, the neutral connection burns out. Now the heavy loads will cause the neutral wire down-stream of the disconnection to appear shorted to L1 and so L2 &L3 will receive almost the full 400V, with the result that TV, microwave, washing machine, lights, etc will burn out, even in some cases when they are in standby mode. - This is probably what Thad E Ginathom could have experienced

The earth wire will sit nicely, as it should, equidistant between the phases. If however a consumer is using the earth wire for return then it could have a voltage drop across it, but that assumes the protection arrangements are not working / installed properly.

I hope this clears things a little.


The pictures for earthing which I couldn't post in this thread but were mailed to John will illustrate this. Hope John will be able to share these pics I sent since I did not know how to post multiple PDF's.

 

[Thad E Ginathom]

My 440v shock to the head was due to a meter fault. My other experience, of 440 volts everywhere in the house was some fault in the street: it was weird, and way beyond my understanding of electricity, because the meter showed 440 whatever I measured. Our local EB man sorted it out within an hour or two. It's good to know such a man; unfortunately ours has been shifted to a different district.

 

[musicbee]

Using UPS, inverter, etc. for protection should only be a 2nd line of defense.

At the minimum you need a circuit breaker. I use Havells and have had no issues the last 6-7 years. It pretty much "trips" at least 2-3 times in a 6 month period... but protects everything including the light bulbs/tube lights.

 

[john_k_antony]

Using UPS, inverter, etc. for protection should only be a 2nd line of defense.

At the minimum you need a circuit breaker. I use Havells and have had no issues the last 6-7 years. It pretty much "trips" at least 2-3 times in a 6 month period... but protects everything including the light bulbs/tube lights.

Are you taking about regular MCB ?

 

[kratu]

Thanks for the warning.

We had severe voltage fluctuations in our neighbourhood in the last week and few days earlier. The power kept going on and off incessantly and the APC UPS kept clicking. Thank God all the equipment is safe. And since last weekend things are back to normal. We thought it is a local issue.

With expensive equipment, I believe we should put budget for good regulators and power conditioners as well.

 

[kanwar]

Fuses/MCBs/RCCBs/GFIs/Surge guards cannot protect against sustainable mains Overvoltage, they only world with mains overcurrent/earth leakage which is different scenario altogether.

 

[kanwar]

It surprises me that why APC is not having any mechanism in their UPS systems to cut-off during overvoltage, owing to the fact here in India the power fluctuation is rampant.

 

[Thad E Ginathom]

My APC UPS does have. Cutting highs and boosting lows; they have their buzz name for it.

Fuses and Circuit breakers are misunderstood by most people. Their purpose is to protect upstream. The fuse in the plug protects against your house wiring burning out; the fuse/mcb at the distribution board protects against the outside cable and local transformer blowing up. The only thing you might have in your distribution box which is designed to protect you is an earth-leakage circuit breaker.

 

[gobble]

Fuses/MCBs/RCCBs/GFIs/Surge guards cannot protect against sustainable mains Overvoltage, they only world with mains overcurrent/earth leakage which is different scenario altogether.

Hi Kanwar
What is the solution then when the line from transformer may give over voltage over long period of time?

--G0bble

 

[Tanoj]

Hi,

Sorry to hear the Frightening power surge at your place,

it is best to get a 3-4 KV 3-Phase Servo Stablizer installed, it will cover whole house, just keep the A/C & Heaters line Seperate ( Bypass the stablizer )

The Stablizer will stablize +/- 3 vs of voltage fluctuation, and it gets turned off at set High/low voltage

We used to use this type of stablizers for photocopiers and they do awesome job

Best inline was Krykard stablizer , Godavari Stablizer, etc

Regards

Tanoj

 

[cyber_cat]

Sorry to hear about your loss John. Faced a similar problem, with neutral and live reversal problem on FEB 11. Luckily only my SMPS blew out along with an adapter and had to run around for RMA. What an ordeal it was.

Considering your losses, I know what you must be going through.

Hope you get a solution.

 

[kanwar]

Hi Kanwar
What is the solution then when the line from transformer may give over voltage over long period of time?

--G0bble

In pro audio we usually face these problems on daily basis, sometimes the 3-phase lines get imbalance and if the unit is operated over diesel genset then there is always a risk of sudden acceleration which can shoot the voltage very high as much as 400VAC.



The best solution which we implement is providing a kit which disconnects the mains voltage from the equipment whenever the voltage drops below 180VAC or goes above 260VAC within 100mS, it is latched operation. Which means once the voltage falls outside of safety window the equipment gets disconnected and the reset is user enabled. The kit is usually installed in stabilizers and servos mostly.


Cheers,
Kanwar

 

[gobble]

John

Time to revisit this thread?
http://www.hifivision.com/what-shou...d-voltage-stabilizer-lcd-tvs-4.html#post88832

Perhaps a simple 50 rupee solution might save the day?

~G0bble

 

[kanwar]

John

Time to revisit this thread?
http://www.hifivision.com/what-shou...d-voltage-stabilizer-lcd-tvs-4.html#post88832

Perhaps a simple 50 rupee solution might save the day?

~G0bble

That is just SURGE protection Varistor , it will only guard against Surges very short bursts of overvoltage spikes, not prolonged mains overvoltage condition.

 

[srisaikat]

I agree with 'Tanoj',

Just use a 3 phase Servo Stabilizer along with Belkin Power Strip like this Amazon.in: Buy Belkin F9S623vzb2M Advanced Series 6 Socket Surge Protector (Gray) Online at Low Prices in India | Belkin Reviews & Ratings which has Rs.50,000 damage coverage for situation like this. I personally use Vertex single phase servo stabilizer which is giving me excellent service for last 7 years. Recently I also purchased V-Guard VM500 along with "Belkin F9S623vzb2M Advanced Series" dedicated for the protection my stereo only. You can also follow the link shared by "gobble" which I think very handy.

 

[ESP]

You need to take these electricity guys to task! What a shocker in the truest sense
How can these people be so callous with life?

I doubt any inverter, surge protector, stabilizer s going to work.

You need to install some kind of kit which kanwar is talking about, I hope he elaborates about it here for everyones benefit

 

[gobble]

http://www.hifivision.com/audio-video-accessories/7364-price-thread-stabilizers-cvt-servo-avt.html

That is just SURGE protection Varistor , it will only guard against Surges very short bursts of overvoltage spikes, not prolonged mains overvoltage condition.

>>>Seems like MOV blew up in both the stabilizer and Emotiva.
I think the culprit was the new age digital stabilizer. It would have worked with a non-spiky relatively stable overload lasting some time but failed on a spike. Would a MOV (or an APC UPS) fail with a steady 320V over voltage or a quick spike? So I think the Varistor would help.

Fellow FM had a bad experience with v-guard too.
See this thread : Horrors in the Apt

Better to invest in a Servo stab as discussed here: price-thread-stabilizers-cvt-servo-avt.html
I just reviewed this thread and it looks like the way to go.

Edit: John, Why didn't you consider a 2KVA Vertex stabilizer for your HT? You have a 5KVA setup for the rest, why ignore the HT? The Vertex Servo may last where the v-guard digi stab failed.

~G0bble

 

[kanwar]

>>>Seems like MOV blew up in both the stabilizer and Emotiva.
I think the culprit was the new age digital stabilizer. It would have worked with a non-spiky relatively stable overload lasting some time but failed on a spike. Would a MOV (or an APC UPS) fail with a steady 320V over voltage or a quick spike? So I think the Varistor would help.

~G0bble

If the MOV has failed it means there was a longer duration spike not any shorter duration. Because MOV is only helpful when the spikes are mostly under 250mS of duration. Longer duration spikes heats up the MOV and they burst in no time.

Also MOV=VARISTOR only because MOV is nothing but Metal Oxide Varistor.

 

[gobble]

If the MOV has failed it means there was a longer duration spike not any shorter duration. Because MOV is only helpful when the spikes are mostly under 250mS of duration. Longer duration spikes heats up the MOV and they burst in no time.

Also MOV=VARISTOR only because MOV is nothing but Metal Oxide Varistor.

I thought the Varistor would blow and fail to conduct electricity therefore everything after than be safe. So I assumed MOV has nothing to do with Varistor.

Ok so how did the varistor fail to work? Because it never hit the limit for it to blow but slowly got simmered and fried instead of popping?

~G0bble