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Old 5th June 2012, 19:05   #46
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Anyone facing any issues with refrigerator cooling due to low voltage ? I got my fridge checked and he said it's all fine, but still cooling is low.
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Old 5th June 2012, 20:52   #47
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I work at a power systems company in Chennai, and it looks to me like the people here in this thread are doing a LOT of dangerous work with electrical equipment!!! In the interest of safety, I wish to add a few points here:

(1) Normally, household wiring is NOT designed to withstand >16 amps of continous current flow (special heavy-duty wires are used very rarely). If you are using using boosters etc. in low voltage conditions, it results in excessive current (18-30 amps) flowing continously through your wires. The copper wire heats up more than usual and the plastic insulation covering it will burn, beyond designed limits. This is a FIRE HAZARD. So check if your wires are really capable of such heavy loads.

(2) Another concern is your electricity meter. Domestic meters are rated for 10-15 amps. This will be stamped visibly on the meter. If you exceed this reqularly, you risk blowing the meter itself. Then your home will be left with NO POWER until the Electricity Board comes to help you!

(3) A quick word about breaker switches (MCB). You will find that your MCB is marked with 20A, 20B, 20C etc., and similarly 16A, 16B, 16C etc. The number (20, 16, 10 etc) is the maximum current beyond which the breaker will trip. The alphabet part (A, B, C) is a code which denotes what type of load is to be connected to the breaker. Thus A and B type breakers are used for normal loads (lights, fans etc) where initial current required is low. But for motors, pumps, A/C etc. the correct type of breaker to use is C. But everybody uses A or B type, because those are cheaper! So if you find your MCB tripping only when the AC compressor comes on, then this could be the problem. So buying a 23A MCB for your 16 amps A/C maybe inviting trouble as given in point (1) above!
I always have a concern about this. Not only is house wiring likely to be underweight, but all joins are likely to be twisted and taped. I don't know why technically (do you?) but overheating seems to especially. happen at these twisted joins. One of these, on our main supply board, actually exploded. I've never gone from asleep to the main breaker so fast!

Thank you for the information about breakers. I never knew about A B and C
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Old 5th June 2012, 21:22   #48
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Hello folks,
I experimented further and swapped the VEW400 over to the 1T AC in the other room to check if that would work well, hoping lesser current draw. It did not blow the fuse, but once it got to 11 PM, the VEW 400 did not even start the 1T Window AC. I rewired at night to even make my 5KVA servo provide input to the VEW400 and then to the 1T AC, still the VEW400 did not start the 1T AC.

I sensed something was wrong with the VEW400 and directly connected the 1T to the servo and the AC started working (though not below 140V as my servo has a low end of 140V).

I worked the phone today with Mercy and then VGuard guys in hopes for a replacement, since the VEW400 was either inherently a defective piece or broken over my 1 week use.

Mercy would not agree for a replacement, instead gave me the VGuard contact number.

I found out the VGuard service place in Chennai
Here's the address
V-guard, 1, Gandhi Road, Gill Nagar, Extension, Choolaimedu, Choolaimedu, Chennai, Tamil Nadu, India
Google maps lead me close to this place and fortunately it was car safe road with somewhere to park.
044-23613499/23613399

(Interestingly, this place is some dealer and has got a warehouse like stock of all VGuard stabilizers and a repair place there itself. Should be useful for those looking to buy a VGuard stabilizer that is in demand at the moment, didnt ask for price though. Several guys bring broken and in-warranty stabilizers to this place. Hard to find such places like these in Chennai towards warranty covered maintenance, in my experience.)

I drove there with my VEW400 and the service personnel tested my VEW 400 and said the coil was weak and I managed to get him to provide a new replacement.

I have now re-wired my 1.5T with the new replaced VEW400. I have also replaced both local MCB and mains MCB with LeGrand C32 MCB in place of the earlier B25 MCB.

I test ran the new replaced VEW 400. It has been working fine so far, but the issues normally start later at night. As of now, I believe, the original VEW 400 had some defect, it made quite some noise compared to the new one I have got.

I will report later if I survive tonight with the new VEW 400 and the two new C32 MCBs.

@Teky - Thanks for the C32 tip and confirmation that VEW 400 does work well with 1.5T AC, I have replaced the MCBs

@Renji - Sincere thanks on your safety tips. My EB meter is type RRC7Y4 and says 10 to 40 A, so looks good to handle up to 40A. My 1.5T Window has 1884 Watts input power rating and 8.4 ampere current as per the AC labels.
I am not sure about my house wiring, I think it is 4 mm sq, but will try to check that again to avoid fire hazard.
I am sure what you mention is a serious threat, for particularly old homes and old wirings.

@Vijay - you have really helped me and others reading this with excellent details and reasoning to get ACs to work in Chennai Many thanks mate!

I hope my fuse does not blow tonight, either way, will look for a proper fuse wire as per your advice and replace the fuse wire.

@manavdotcom - Yes, my refrigerator was almost entirely out during the nights, until I put a premier single AC stabilizer (the one that my VEW 400 replaced) to power the refrigerator. This has improved the refrigerator to hold on better during the night. You may want to look for some spare stabilizer like what I did. You may also refer to Thad using a double boost for his microwave in this thread.

I am really worried that my house is now filled with stabilizers, I am sure Chennai is now filled at homes with stabilizers than ever, wish TNEB will improve the transmission standards.
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Old 5th June 2012, 23:24   #49
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You may be right but I still dont see any wire related issues even at 120V. Mostly all new installations will use typical wiring 4.5 Sq.mm wire for upto 1.5T A/C's and 7 Sq.mm for 2T A/C's. Barring older generation A/C's all latest generation use 1800W max which is same as 15 or 20 liter geyser. Being resistive load it sucks current like crazy compared to inductance load. Also the calculator say's upto 2KW @ 120V need 4Sq.mm thick wire, I dont see any issues.
Just checked the house hold meter its 3Ph. 40A meter
Voltage Drop Calculator
Dear vijaycool,
Not to under-estimate your logic, but I have made a more realistic calculation for you here. I have changed just two values from yours ie "Application" and "Number of Circuits". Application is IN CONDUIT IN AN INSULATED WALL, because in India most of household wiring is done by passing cooper-wire cables through PVC conduits concealed inside brick walls. Also, Number of Circuits is 2 BUNCHED TOGETHER, because if you observe the wiring coming out of your Main DB, you will see a mess of wires bunched along with your AC's power cable! I have taken 2 for minimum reference, although in reality it is much more. Now if you look at the maximum current, I hope it is clear why I am emphasizing on electrical safety here.
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Old 5th June 2012, 23:42   #50
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I always have a concern about this. Not only is house wiring likely to be underweight, but all joins are likely to be twisted and taped. I don't know why technically (do you?) but overheating seems to especially. happen at these twisted joins. One of these, on our main supply board, actually exploded. I've never gone from asleep to the main breaker so fast!

Thank you for the information about breakers. I never knew about A B and C
Hi Thad,

Sorry to hear about your "explosion" !!! Yes, this is exactly what I was talking about in terms of electrical safety. In your case, it might have been an improper wire-joining technique done by the electrician who initially worked on you Mains. There is unusually high resistance to power flow at improper joints, causing the cables to melt/burn at the joint, and the heat burns the nearby cables also. It is sadly very common to see electrical fires caused by joining wires incorrectly. Thats why, if you check any published book about wiring and cabling, there will be a whole chapter dedicated to joining wires safely!!
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Old 6th June 2012, 01:29   #51
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There is unusually high resistance to power flow at improper joints, causing the cables to melt/burn at the joint, and the heat burns the nearby cables also
Absolutely this must be the answer. I have little faith in the electricians that wired my house, but it is no good being wise after the event. I must, at least, get those twisted joins, which are in cables to the phase selectors, replaced by continuous cable, or at least, screw-block connectors.

Those of us who have "upgraded" to double-boost stabilisers should certainly check the supply cable thickness. At least our AC stabilisers are located near the distribution box, so the higher-current run is not so long.
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Old 6th June 2012, 09:05   #52
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Originally Posted by renji3 View Post
...In the interest of safety, I wish to add a few points here:...
Thanks a lot, renji3 . You have rightly highlighted the safety aspects related to electrical wiring in the house.

Lot of useful info there too...didnt know about the significance of the A/B/C notation in MCBs. Thanks !
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Old 6th June 2012, 21:53   #53
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... Thats why, if you check any published book about wiring and cabling, there will be a whole chapter dedicated to joining wires safely!!
Coming back to this, can there be a right way of twisting cables together?
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Old 6th June 2012, 23:37   #54
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Coming back to this, can there be a right way of twisting cables together?
Hi Thad,

This link can provide a few clues. Check pages 2-5 to 2-10 in the following PDF:

http://www.cedengineering.com/upload...Techniques.pdf

The material is a basic course for various State Licensing Exams for electricians in the USA. Even in India, there are similar exams, but I wonder how many electricians actually take a licence for household electrical work!
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Old 7th June 2012, 21:05   #55
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Very useful; thank you. I'll keep a copy of that in my digital library.
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Old 8th June 2012, 14:09   #56
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Yesterday was very bad.

Low voltage all afternoon; very low voltage all evening; no voltage from about 11.00pm to around mid-day today.

Even though I do not like fans, I was glad that we had the inverter to keep one going in the 31C bedroom all night.
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Old 8th June 2012, 22:01   #57
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Okay I got a V-Guard VWR400 double boost stabilizer with my new A/C. Works fine. Comes with a digital display for input and output voltages. Costs 3.6k in Rathna Fan House and works like a charm. Those with low voltages can get this one. It picks voltage up from 130V.

Cheers,
K
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Old 8th June 2012, 22:15   #58
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Low voltage all afternoon; very low voltage all evening; no voltage from about 11.00pm to around mid-day today.
...And further cuts in the afternoon and evening.

I wish they would go back to two scheduled hours of cuts. At least the voltage was better for the rest of the day.
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Old 9th June 2012, 11:38   #59
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...And further cuts in the afternoon and evening.

I wish they would go back to two scheduled hours of cuts. At least the voltage was better for the rest of the day.
Yeah the scheduled power cuts were much better. Today early morning @ 3Am I woke up because of no power. 2 days before there was no power till 12.45 AM . ceiling fans doesnt help in giving comfort rather it sucks the heat from the ceiling and circulating to the entire room.
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Old 9th June 2012, 11:45   #60
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Okay I got a V-Guard VWR400 double boost stabilizer with my new A/C. Works fine. Comes with a digital display for input and output voltages. Costs 3.6k in Rathna Fan House and works like a charm. Those with low voltages can get this one. It picks voltage up from 130V.

Cheers,
K
It will work till 130V if the compressor is running. It cannot start the compressor if the voltage is less than 160V. Anyway it has the IP voltage reading you can monitor few days.
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