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how to calculate load for protection from Surge

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mahiruha

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Hello Guys,
just 2 days back I had a pretty bad experience while listening to music. There was fire in the electricity cables near my house although electricity was runnuing but the music stopped suddenly. I thought some equipment must have given in but when cesc guys repaired the lines I tested everything and they were working. I really don't know what hapeend really but I would like to take future protection against such incidence. My question is what is the best possible protection agaist this kind of things. Is it to put a voltage stebilizer. If I need to get a voltage stabilizer then how do I calculate the load. I am using
1) Cabridge audio 540D V2 DVD player
2) Lyrita pre amp
3) Lyrita 6c33c integrated amp
4) Project debut 3 turntable
5) Onkyo TXSR 705 receiver
6) Sanyo plv z5 projector

I guess it is also a good idea to get a protection for my bedroom as well as same thing can happen there. The list of equipments are
1) Samsung 40" LCD tv
2) Sony dvd player
3) Xbox 360
4) Logitech squeezebox
5) Netgear eva 8000 wireless receiver
6) Sony dav HT system.
If somebody cab provide some idea in this matter that will be really helpful.
Thanks,
Mahiruha.
 

AMITNOIDA

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Separate equipment with switching supplies and linear supplies.

Typically, all audio equipment barring a few have linear supplies and are best connected on an individual line with surge and overload protection. A Circuit breaker (6A) will take care of overload, surges are a little tougher to protect against but a certified surge guard is a good idea.

Normally I rail against monster products, but the connected equipment warrany actually makes buying their entry-level spike guard a good idea. I think it's 5K.

Voltage stabilisers don't work for audio, not even servos. Their reaction time is much slower than they should be (~100ms) when what you need is about 10ms. For video, they are a decent idea, if the mains in your area fluctuates a lot.

Cranky, few peoples suggest Isolation transformer. Does it do surge and overload protection? In some thread there was suggestion for Krykard Servo stabiliser (2 KVA with RFI-EMI protection module). Is it worth considering?
 

mahiruha

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Separate equipment with switching supplies and linear supplies.

Typically, all audio equipment barring a few have linear supplies and are best connected on an individual line with surge and overload protection. A Circuit breaker (6A) will take care of overload, surges are a little tougher to protect against but a certified surge guard is a good idea.

Normally I rail against monster products, but the connected equipment warrany actually makes buying their entry-level spike guard a good idea. I think it's 5K.

Voltage stabilisers don't work for audio, not even servos. Their reaction time is much slower than they should be (~100ms) when what you need is about 10ms. For video, they are a decent idea, if the mains in your area fluctuates a lot.

Hello Cranky,
thanks for your reply.Well the area I live in doesn't have too much of voltage fluctuation. Actually I don't understand why only one refrigarator is having voltage stabilizer in my house.Lot of more sophisticated gadgets have come in after that and they are working fine over years witout any issue. I guess it is more of a legacy issue rather than voltage issue. Now I have circuit breakers installed all over my house if I am not mistaking those tiny black things called tiny trip C 20 A MCB as circuit brekaers. Your suggestion about this monster surge protector seems to be a good idea. I have two surge protectors from belkin costing around Rs800.Are they simialr thing or the monster has some advanced circuitry built in. do you know any place where from this protectors can be sourced. The current protectors I am just using a extentension corrd for the things that cannot be accomodated in the main plug. In my current set up the dvd player , sub woofer and the tt are connected to the belkin. I was told that tube gadgets are really solid and not prone to this voltage issue but can they be damaged when two overhead lines touches each other by accident and leads to fire.
This is a tail probability event. But in a state like WB with such a wonderful governance I can't really fully factor out these events.
Thanks,
Mahiruha.
 

Asit

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Hi,

I have questions and comments.

What I find in my area (which is close to Mahiruha's) there are no huge voltage fluctuations during 'good' periods. Since my home is just next to my office and served by the same power line and there are better and more sophisticated instruments in our office infrastructure to make measurements on these things, it's not that difficult for me to make some judgement.

However, during 'bad' periods two things generally happen: 1) there are low voltages, 2) there are occasional surges.

Now for the past few months I have a Krykard 3 KVA servo stab installed for all my AV rig. Before that installation, on a few occasions, my CDP during normal playing operation suddenly stopped and switched to standby mode, similar to what happened to mahiruha's equipment.

I was aware (although not quite sure about the exact numbers, but of the order of a few tens of millisec) that the response time of a servo may be a bit off for optimal effect in an audio equipment. However, it still should have some positive effect although not absolutely perfect. No instrument in this world will ever be perfect (i.e. infinitely precise) and would always come with a tolerance. For example, my servo is set to 230V and can fluctuate 1% around it. The question is if my equipments can take that tiny fluctuation and a bit of a lag in response and still perform at an optimal level.

A good servo stab (with a good servo motor and transformer) like mine has hard lower and upper cutoff voltages and can come also with much much better spike busters (with a good response time, microsec or nano sec, not sure) and RFI/EMI filters than usually available in consumer AV stores and music outlets. It will also provide a sinusoidal voltage supply unlike many offline (and affordable) UPS.

After I had my servo installed in my chain, so far there have not been any stoppages in my equipments.

I am not trying to justify anything. I have plainly laid out my thinking (which may be wrong) and am inviting comments from everybody including technical experts like cranky.

Regards.
 

westom

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Now I have circuit breakers installed all over my house if I am not mistaking those tiny black things called tiny trip C 20 A MCB as circuit brekaers. Your suggestion about this monster surge protector seems to be a good idea. I have two surge protectors from belkin costing around Rs800.Are they simialr thing or the monster has some advanced circuitry built in. do you know any place where from this protectors can be sourced.
None of that provides surge protection. Let's start with what Belkin and Monster claim. Show me their spec numbers that claim protection from each type of surge. Neither make any claims because neither claims to provide that protection.

Let's look at some embarrassing numbers. Will the 2 cm part inside that protector stop what 3 kilometers of sky could not? Of course not. Will its few hundred joules absorb a surge that is hundreds of thousands of joules. Of course not. An overwhelming majority will recommend those protectors because that was the first recommendation their heard. And because they completely ignore those numbers.

Now, circuit breakers are not for appliance protection. Circuit breakers are for your protection AFTER the appliance has been damaged. So that a fire does not happen.

Again, numbers. Surges are done in microseconds. Circuit breakers (at best) take tens of milliseconds to respond.

Notice who posts numbers - the reasons why - with recommendations. That is your benchmark. Only those trained in this stuff should have your attention. That means reasons why - and numbers.

What does that UPS do? Provide electricity when voltage approaches zero. What are surges? Voltage massively exceeds 230 volts. View the numbers. Even surge protector remain disconnected - does nothing - until voltage exceeds 500 volts. What is the UPS for? Events where voltage drop to near zero. UPS does not provide effective surge protection. But when playing games of subjective reasoning (no numbers), the sales brochure could even claim to prevent Armageddon - the end of civilization as we know it.

How do telcos operate without damage? Over 100 years of science confirmed by experience defines one item always required for surge protection - single point earth ground. Which protectors actually provide protection? Ones that connect short (ie 'less than 3 meters) to earth. A protector without that earthing wire - well where are those spec numbers from Belkin and Monster that claim protection? Do not exist. Cannot exist. No short connection to earth is your first indication. Same reason why telcos waste no money on Belkin and Monster products. Instead earth 'whole house' protectors.

How often has your town been without phone service for four days? Earthing a protector is that effective - no damage even from direct lightning strikes.
 
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mahiruha

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Hello westom,
thanks for your thoughtful reply. My house is pretty well earthed. But when you earthing a protector why do you mean precisely. My knowledge about electricity is pretty limited. Do you mean to say I get surge protector and from that protector I connect a manual wire to the earth???
Luckily I have few tall buildings around my house so my house is relatively safe from lightning.
Thanks.
 

suri

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None of that provides surge protection. Let's start with what Belkin and Monster claim. Show me their spec numbers that claim protection from each type of surge. Neither make any claims because neither claims to provide that protection.

Let's look at some embarrassing numbers. Will the 2 cm part inside that protector stop what 3 kilometers of sky could not? Of course not. Will its few hundred joules absorb a surge that is hundreds of thousands of joules. Of course not. An overwhelming majority will recommend those protectors because that was the first recommendation their heard. And because they completely ignore those numbers.

Now, circuit breakers are not for appliance protection. Circuit breakers are for your protection AFTER the appliance has been damaged. So that a fire does not happen.

Again, numbers. Surges are done in microseconds. Circuit breakers (at best) take tens of milliseconds to respond.

Notice who posts numbers - the reasons why - with recommendations. That is your benchmark. Only those trained in this stuff should have your attention. That means reasons why - and numbers.

What does that UPS do? Provide electricity when voltage approaches zero. What are surges? Voltage massively exceeds 230 volts. View the numbers. Even surge protector remain disconnected - does nothing - until voltage exceeds 500 volts. What is the UPS for? Events where voltage drop to near zero. UPS does not provide effective surge protection. But when playing games of subjective reasoning (no numbers), the sales brochure could even claim to prevent Armageddon - the end of civilization as we know it.

How do telcos operate without damage? Over 100 years of science confirmed by experience defines one item always required for surge protection - single point earth ground. Which protectors actually provide protection? Ones that connect short (ie 'less than 3 meters) to earth. A protector without that earthing wire - well where are those spec numbers from Belkin and Monster that claim protection? Do not exist. Cannot exist. No short connection to earth is your first indication. Same reason why telcos waste no money on Belkin and Monster products. Instead earth 'whole house' protectors.

How often has your town been without phone service for four days? Earthing a protector is that effective - no damage even from direct lightning strikes.

hi westom,

what about this scenario ?-

lightning strike on the overhead line that supplies the house. there will be a surge of voltage at all power outlets in the house, and earthing the equipment will not prevent damage to the appliance. If there is something between the power point and the appliance that can blow, perhaps the appliance sought to be protected will be saved

in a three phase supply, if the neutral blows, double the voltage is supplied to the power points in that line (this, if i am not mistaken), and instead of 220 volts, 440 v is supplied. How will earthing prevent damage to the equipment so supplied with high voltage beyond it's capacity to endure?

i have noted your point about direct lightning strikes, but i think mahiruha is talking about protecting his equipment from high voltage surges in the domestic power supply, and not direct lightning strikes.

regards
 
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westom

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My house is pretty well earthed. But when you earthing a protector why do you mean precisely. My knowledge about electricity is pretty limited. Do you mean to say I get surge protector and from that protector I connect a manual wire to the earth???
A safety ground on a wall receptacle is not earth ground. Earthing means every wire inside every incoming cable connects short (ie 'less than 3 meters') to an earthed electrode - ie ground rod. Safety ground wire to receptacles is longer. Too long (and sharp wire bends, bundled with other wires, etc) to provide earthing.

Telephone cable contains two wires. Both must connect short (no sharp wire bends, no splices, not inside metallic conduit, etc) to earth. But if connected directly, then phone service is lost. So we make that earthing connection via a protector.

Essential is not wire thickness (to lower resistance). Essential is wire length (to lower wire impedance). Also essential is that every incoming wire be connected to the same earthing electrode before entering the building. Single point earth ground.

Coax wire (cable TV or satellite dish) is connected directly. No protector required. A ground block connected less than 3 meters to earth means surge currents need not enter the house to find earth destructively via appliances.

All incoming AC electric wires (not just the neutral) also must be earthed - again via a 'whole house' protector.

Electronic appliances are required to withstand minor voltage increases (variations) on AC mains. For example, 230 volts electronics even in 1970 standards would withstand up to 1100 volts without damage. Today, some computer interface chips are now required to withstand 2000 or 15,000 volts without damage.

Protection that is found inside all appliances can be overwhelmed by the rare transient. Earth one 'whole house' protector so that all (maybe 100 appliances) are protected from an event that typically occurs once every seven years.

What will a UPS do? Protection routinely inside computers is also inside the UPS. If a computer needs protection, then so does the UPS. Just another reason why a 'whole house' protector is earthed. International standards require electronics to operate unharmed during lesser voltage variations. The same robust 'whole house' protector also makes lesser transients irrrelevant.
 

suri

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A safety ground on a wall receptacle is not earth ground. Earthing means every wire inside every incoming cable connects short (ie 'less than 3 meters') to an earthed electrode - ie ground rod. Safety ground wire to receptacles is longer. Too long (and sharp wire bends, bundled with other wires, etc) to provide earthing.

Telephone cable contains two wires. Both must connect short (no sharp wire bends, no splices, not inside metallic conduit, etc) to earth. But if connected directly, then phone service is lost. So we make that earthing connection via a protector.

Essential is not wire thickness (to lower resistance). Essential is wire length (to lower wire impedance). Also essential is that every incoming wire be connected to the same earthing electrode before entering the building. Single point earth ground.

Coax wire (cable TV or satellite dish) is connected directly. No protector required. A ground block connected less than 3 meters to earth means surge currents need not enter the house to find earth destructively via appliances.

All incoming AC electric wires (not just the neutral) also must be earthed - again via a 'whole house' protector.

Electronic appliances are required to withstand minor voltage increases (variations) on AC mains. For example, 230 volts electronics even in 1970 standards would withstand up to 1100 volts without damage. Today, some computer interface chips are now required to withstand 2000 or 15,000 volts without damage.

Protection that is found inside all appliances can be overwhelmed by the rare transient. Earth one 'whole house' protector so that all (maybe 100 appliances) are protected from an event that typically occurs once every seven years.

What will a UPS do? Protection routinely inside computers is also inside the UPS. If a computer needs protection, then so does the UPS. Just another reason why a 'whole house' protector is earthed. International standards require electronics to operate unharmed during lesser voltage variations. The same robust 'whole house' protector also makes lesser transients irrrelevant.

all incoming ac wires are earthed - directly = short = no current/voltage to the house.

So, how is it done? - a relay which switches to earth when the line voltage is exceeded beyond tolerance?

your points are noted , but please give us a practical demonstration of how to effect theory that you have elaborated.

regards
 

suri

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Electreonic appliances are required to withstand minor voltage increases (variations) on AC mains. For example, 230 volts electronics even in 1970 standards would withstand up to 1100 volts without damage. Today, some computer interface chips are now required to withstand 2000 or 15,000 volts without damage.

Yes, but limited to a time frame - perhaps milliseconds - what happens when there is a surge over 2 seconds? - happens all over the voltage supplied world, happens in Kolkata, has happened in Kannur where I live.

the appliance will blow. No voltage-sensitive equipment will survive a sustained voltage surge.

So please guide (us interested people) how to go about this process of protecting our audio/video equipment.

regards
 

suri

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westom - there's a pretty big difference in power conditions between the US and India.

For the most part, it's a public-owned service, which basically means substandard equipment and terrible power quality. Extended brownouts usually cause havoc - we've seen voltages dip to 160V for periods up to 10 minutes, and overvoltage lasting half the night (though this is mostly due to improper load balancing than equipment, ergo, operator error).

Till a few years back, it was pretty much mandatory for anybody with sensitive equipment to use so-called 'voltage stabilisers', to boost or buck the line depending on incoming voltage. In most of the country apart from the large metropolitan centers, this is de rigeur even today.

suri, westom is talking about earthing connections, not live :) and he's on the money. We bring up a single wire to the board and route the entire house earthing back to one wire. The earth wire needs to have the lowest impedance of all the wires in the building, as it is the only thing that is protecting the user.

In any case, the poor power conditions cannot be helped by good earthing. Thermistors do help somewhat, but they don't hold up very well over the tens of seconds of fault conditions common in India.

AHHHHH westom! Now i get it! Eureka! (i discovered that i have a fuddled mind!):)

and there is something about adding rock salt every now and then to the ground electrodes.
 
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westom

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We bring up a single wire to the board and route the entire house earthing back to one wire. The earth wire needs to have the lowest impedance of all the wires in the building, as it is the only thing that is protecting the user.
That is a safety ground wire. It must be low resistance. It cannot be low impedance. Wire too long. Too many sharp bends. Etc.

Earth ground means a less than 3 meter connection to earth. Some have used rock salt for better earthing. Others accomplish the same by expanding the earthing system. See Ufer grounds as one example.

If voltages are so extreme as to cause electronics damage, then electric motors have an even higher failure rate. What happens when 230 volts drops to 160 volts? Either electronics work normally or electronics shut off normally. That same voltage would harm electric motors.

How often do your lights glow 40% brighter? That voltage increase is also a normal voltage to any electronics - according to the numbers you are provided. When we design hardware, the actual normal maximum voltage is even higher.

So what would a UPS do? Same voltage extremes that would damage electronics would also damage that UPS. Anything a Belkin or Monster would claim to do is better solved by one 'whole house' protector.

Unfortunately, discussion has been confused by lumping completely different electrical anomalies as if all were same. 1) Anomalies that are typically destructive require a protector that is earthed (safety ground is not relevant - an effective solution even if the building has no safety grounds). 2) Anomalies that would cause lights to glow 40% brighter are addressed (solved) inside electronics but can be harmful to electric motors. 3) Anomalies that cause lights to dim less than 50% or more are not destructive to electronics but can be harmful to electric motors.

Anomaly 3 is why a UPS is used. So that unsaved data in electronics (computer files or video recording) is not lost. That UPS is not for hardware protection. A UPS is for data protection.
 

suri

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Hi westom,

never knew about "whole house surge supressors/protectors"

been researching since yesterday, and here is a thread from another forum-

Whole House Surge Protectors - dslreports.com

certainly will locate and install a "whole house surge protector", as a first line (probably only) defense against destructive surges.

and a sort of summing up in the thread mentioned above--


The most important thing to note about whole-house surge protection devices is that they should be installed with as short a wire run as possible between the surge protector and the breaker they attached to. The shorter the run, the faster their reaction time, and the more energy they will be able to absorb. If done in this manner, they will work fine to protect electronics that are typically much further in wire length away from the source of the surge, unless the surge occurs between the device to be protected and the surge protector. Having both a whole-house protector and a remote protector at the electronics devices is recommended. (Don't forget to protect any low voltage wiring entering the house, like CATV & telephone wiring.)
to forum permalink [Encourage,Ignore,Watch] 2009-03-07 11:17:48 Reply to this


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said by whizkid3 See Profile :

Having both a whole-house protector and a remote protector at the electronics devices is recommended. (Don't forget to protect any low voltage wiring entering the house, like CATV & telephone wiring.)
That is the key to effective protection.

1) Perimeter protection
All copper is protected and bonded to building ground system even antennas where it enters the building. That insures all "services" are equipotential during a disturbance.

2) Point of use Protection
To be maximally effective everything entering the device should pass though point of use protector. Again purpose is to clamp transient voltage and minimize voltage differences between services.


THANKS WESTOM, did learn something new and useful today (probably life-saving too).:)

add - most houses have an "ELCB" (earth leakage circuit breaker) - which supposedly opens the Main circuit, if it detects a ground leak in connected appliances - so in a home with overhead power line supply, if the neutral blows, and supplied voltage on one leg goes double, at some location in the house the (first) point-of-use protector will fry and then earth, and the instant it does that, the ELCB will open the main power circuit and thus prevent frying of other point-of-use protectors.

summing up then

(1) perimeter protection
(2) point-of-use protection
(3) ELCB breaker protection

should complete the ring of protection, should it not?
 
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mahiruha

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Hello Guys,
I started this thread wondering how things should be protected. Only last Thursday I experienced how things can go wrong. There was a sudden blow up in voltage from our good old CESC and I had a huge list of casualties.
xbox 360
Netgear wireless receiver
ADSL modem power adapter
Wireless router power adapter
Computer speaker
one LCD tv
Luckily I didn't have any a/v gear switched on. Both my wirelss receiver and xbox 360 were connected to a Belkin surge protector. From my experience it is quite useless.Another funny thing is in one of the room the power went off as the circuit breaker tripped but the pc still got damaged and the lcd tv which was on didn't suffer any ill fate. My bedroom computer was on but it was saved as it was connected to a UPS. Not sure about the role of voltage stabilizer though. Since one refrigarator was connected to a voltage stabilizer and another one didn't have any voltage stabilizer and nothing happened to both of them. I have been living in this house for last 28 years and this is the first time something like this has happened. The effets are really catastrophic. I have to take some serious steps against things like that. I am thinking in the line of some mechanism in the main input of the house which will trip if there is a surge. MY electrician was talking something like but I am not sure what it is. Has anybody done something like that in their house?
Thanks.
 

venkatcr

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That is quite a set back Mahi.

Unfortunately as Westom has very well put (and this is something I have been saying repeatedly) nothing can save you from lightning strikes and huge surges. Belkin is playing the same game that insurance companies are playing. Insure a 100 guys and if 2 die, on the average, you yet make money from the other 98. Quietly pay the 2 who died. It is that simple.

If you are in the ground floor, it is worthwhile spending money to dig a pit and install a proper earthing system. This should be as close to the termination points where CESC main supply comes to your house. Lay a thick copper rod from the pit and bring it up to a termination point on you main board.

For added safety can you insure all you products?

Cheers
 

westom

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... the ELCB will open the main power circuit and thus prevent frying of other point-of-use protectors.

An ELCB (also called RCD or GFCI) will not do that. Its function is to protect only human life. If it opens, a transient will easily jump its millimeter gap. Plasma will form bridging that gap. Current will continue to flow.

Furthermore, the ELCB takes milliseconds to respond. Surges are done in microseconds.

Two reasons why an ELCB will not protect any electronic devices.
 

mahiruha

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That is quite a set back Mahi.

Unfortunately as Westom has very well put (and this is something I have been saying repeatedly) nothing can save you from lightning strikes and huge surges. Belkin is playing the same game that insurance companies are playing. Insure a 100 guys and if 2 die, on the average, you yet make money from the other 98. Quietly pay the 2 who died. It is that simple.

If you are in the ground floor, it is worthwhile spending money to dig a pit and install a proper earthing system. This should be as close to the termination points where CESC main supply comes to your house. Lay a thick copper rod from the pit and bring it up to a termination point on you main board.

For added safety can you insure all you products?

Cheers
Hello Venkat,
thanks for your reply.As far I remeber this process of earthing was done elaborately few years ago by digging a pit and following all the rituals. I will definitely ask the electrician to make sure that everything regarding earthing is ok and and attach a copper rod as suggested by you. I also made a strange observation that the gadgets that have inbuilt power supply are gone completely but the gadgets that has an external adapter they are ok only the adapters are damaged. What is so special about those adapters? I think the surge just fries anything that it finds in the first point of entry in to the electronics. So it is the adpater for gadgets that has external adapter and the power supply unit for the other gadgets.I am also surprized that the Belkin surge protector itself survived although it failed to protect any surge.
Thanks.
 

venkatcr

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I also made a strange observation that the gadgets that have inbuilt power supply are gone completely but the gadgets that has an external adapter they are ok only the adapters are damaged. What is so special about those adapters?

Essentially, when a power supply is built into the unit, the distance between the output of the power supply and the first point in the board inside is very short. A surge not only will fry the power unit, it may also travel raw through the power supply to the board before it gets grounded or dissipated. This may not happen every time, and in many cases, it is possible only the internal power unit is fried and surge has been grounded. The main unit may yet function if the power unit is replaced.

In an external power unit, there is distance for the current to travel to the main unit and there are a couple of additional steps for the current to travel. When the external power adapter fries, it may just die there, the surge may get earthed, the cable travelling to the main unit may burn not allow the surge to travel any more. In most cases the main unit may survive reducing your loss. But there is no guarantee. If the surge/spike is strong enough it may travel to your main unit before it gets earthed or dissipated or burns the connecting wire.

I am also surprized that the Belkin surge protector itself survived although it failed to protect any surge.

You mean stop the surge? Belkin may have designed the internals of the protector and used materials that can withstand high voltages. But the fact that it did not stop the surge is a flaw.

Cheers
 
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