Mains Voltage Surge Protection

[westom]

Hmm - thanks for the link - says it needs an earth

An external isolation transformer is earthed for human safety.

Meanwhile, appliances already contain an isolation transformer - also called galvanic isolation. Required firstmost for human safety. Anything that isolation transformer or on-line UPS would do is already standard inside appliances.

Notice the app note discusses noise. It does not discuss a transient that can overwhelm protection already inside all appliances. Your concern is that rare transient (typically once every seven years) that overwhelms existing superior protection.

Previously posted was

Investigation means you have numbers that claim protection. If a UPS (which is a power supply) does that protection, then the superior supply already inside every electronic device does that protection better. If a surge blew through an appliance power supply, then if easy blows through a UPS. View its spec numbers.

So where are relevant spec numbers? Subjective recommendations are how junk science and myths get promoted. Galvanic isolation already inside appliances is why appliances will withstand 600 or 1000 volt transients without damage.

If an online UPS does protection, then spec numbers are also included to define that protection. View its numbers. According to the manufacturer's numbers, an online UPS typically claims less protection than a power strip. IMHO has accurately defined the only significant function provided by a UPS. Temporary and dirty power during a blackout.

Edited December 24, 2012 by westom

[jpinx]

If you're happy with the placebo effect, go ahead and buy a cheap ups as many posters have advised.

But if you want proper protection, you must buy an ONLINE UPS. These are not cheap like their 'line interactive' brethern but they're the only ones that truly protect you from dirty input power. The cheap, line-interactive UPS's ("with built-in surge protection"), their surge protection is no better (probably worse) than the surge protection already in your tv's power supply.

Also, if you want surge protection to work at all, you will need to earth your setup.

Another alternative if for some reason you can't get a good earth is a simple 1:1 line isolating transformer.

ok I'll bite -- What's one of those?

I believe bobl is talkign about something similar to what I use, but also including battery backup - though we're not talking about PC's that need to safely shutdown here so I fail to see the point in a UPS that will run your TV & stereo gear for an extra few minutes during a blackout..

A device that fully isolates the incoming supply from the socket is the only one I'd connect my gear to - most consumer grade UPS's dont' do this - they simply provide a rudimentary 220VAC failover that will give you a few minutes to safely shutdown your computer in the event of a black/brown out.

UPS only came into the conversation because it was suggested somewhere that UPS is the only way to genuinely isolate the spiky voltage from the device without needing an earth. The device you refer to does not say on the page if it needs an earth or not, and 500W is an overkill for a 24" lcd screen that's pulling about 60w, but I appreciate the pointers - I'm still looking

[westom]

UPS only came into the conversation because it was suggested somewhere that UPS is the only way to genuinely isolate the spiky voltage from the device without needing an earth.

Some of the 'spikiest' power comes from a UPS in battery backup mode. May be so 'spikey' as to even be harmful to small electroc motors and power strip protectors. Why is this recommended for electronics? Because superior protection already inside electronics makes 'spikey' power from a UPS irrelevant. And numbers have already been provided that defines why electronics make 'spikey' UPS power irrelevant.

You have assumed spikey power caused damage. So how many other appoliances are also damaged? Noted long ago, no other appliance damage implies failure from something far more common - manufacturing defect.

Edited December 24, 2012 by westom

[jpinx]

Well -- the internal overvoltage protection in my lcd didn't protect it very well, as I am now replacing the power board. I was hoping for a surge preventer, it can cause shutdown if needed. The complication is no earth being available. This condo block just does not have earth anywhere - I've looked,,,,,

Edited December 24, 2012 by jpinx

[IMHO]

The device you refer to does not say on the page if it needs an earth or not, and 500W is an overkill for a 24" lcd screen that's pulling about 60w, but I appreciate the pointers - I'm still looking

It definitely does need an Earth I'm afraid

And yes, overkill for a tiny 24" LCD - unless you power your stereo, PC, DSL modem or anything else that could use clean power off it too

[jpinx]

UPS only came into the conversation because it was suggested somewhere that UPS is the only way to genuinely isolate the spiky voltage from the device without needing an earth.

Some of the 'spikiest' power comes from a UPS in battery backup mode. May be so 'spikey' as to even be harmful to small electroc motors and power strip protectors. Why is this recommended for electronics? Because superior protection already inside electronics makes 'spikey' power from a UPS irrelevant. And numbers have already been provided that defines why electronics make 'spikey' UPS power irrelevant.

You have assumed spikey power caused damage. So how many other appoliances are also damaged? Noted long ago, no other appliance damage implies failure from something far more common - manufacturing defect.

Fair comment, but there's nothing else vulnerable. The laptop is isolated by it's battery. Having said that, I am on my 2nd transformer plug for the laptop, but difficult to know what caused the old one to give up - spiky voltage or just dodgy components.

fwiw - when the power dies here and comes back on - it comes back with a bang and makes my floorfan jump (and me). I get a big outage like that about once a week

Edited December 24, 2012 by jpinx

[IMHO]

The laptop is isolated by it's battery.

I'm afraid that's not the case.

[westom]

Well -- the internal overvoltage protection in my lcd didn't protect it very well, as I am now replacing the power board.

And replacing the power board in how many other appliances? If you had damage from spkey power, then you typically have many damaged appliances. One failed LCD is a classic manufacturing defect. As was explained in a first post.

[jpinx]

The device you refer to does not say on the page if it needs an earth or not, and 500W is an overkill for a 24" lcd screen that's pulling about 60w, but I appreciate the pointers - I'm still looking

It definitely does need an Earth I'm afraid

And yes, overkill for a tiny 24" LCD - unless you power your stereo, PC, DSL modem or anything else that could use clean power off it too

My "tiny" 24" lcd TV monitor is the only thing apart from the transformer plugs for mobile phone, laptop, shaver, and a mains/usb power thingie to power my sound system. I only got the lcd because I'd like to watch a movie on a screen marginally bigger than a sheet of A4

I'm debating with myself about a lash-up of a mains battery charger connected to a 12 v car battery connected to one of those little 12v-mains inverters. Anyone care to comment ?

[jpinx]

The laptop is isolated by it's battery.

I'm afraid that's not the case.

Interesting comment. The laptop is recharged by a plug transformer - not by mains direct into the laptop. The voltage output of the plug transformer is DC 9 volts - not sure how you believe that is affected significantly by spikes in the input AC.

Edited December 24, 2012 by jpinx

[westom]

I'm debating with myself about a lash-up of a mains battery charger connected to a 12 v car battery connected to one of those little 12v-mains inverters. Anyone care to comment ?

Already answered:

Some of the 'spikiest' power comes from a UPS in battery backup mode. May be so 'spikey' as to even be harmful to small electroc motors and power strip protectors.

One function inside every UPS is an inverter that creates the 'spikiest' power. Your idea is a UPS mising the switch to disconnect AC mains and switchover to battery. And a tiny charger that takes hours to recharge a battery after discharged in minutes.

[Pib]

The laptop is isolated by it's battery.

I'm afraid that's not the case.

Interesting comment. The laptop is recharged by a plug transformer - not by mains direct into the laptop. The voltage output of the plug transformer is DC 9 volts - not sure how you believe that is affected significantly by spikes in the input AC.

Laptops I've owned do not need the battery installed to operate. With the power adapter/charger (i.e., like a DC 9 volt input mentioned) plugged into the laptop it's doing two things: powering the laptop and charging the battery. Turn off/unplug the power adapter and the laptop draws all its power from the battery vs the power adapter input voltage.

[IMHO]

The laptop is isolated by it's battery.

I'm afraid that's not the case.

Interesting comment. The laptop is recharged by a plug transformer - not by mains direct into the laptop. The voltage output of the plug transformer is DC 9 volts - not sure how you believe that is affected significantly by spikes in the input AC.

How does a notebooks's switchmode power supply differ from the switchmode power supply in an LCD TV?

[jpinx]

yea - well - I am not deeply immersed in the technology - I just wanted my TV to not get fried

[IMHO]

yea - well - I am not deeply immersed in the technology - I just wanted my TV to not get fried

All electronic devices running off mains AC have a power supply of some description - and it doesn't matter if that's in the form of a plug-pack or an internal power supply - they're all just as fundamentally susceptible to damage from spikes as each other...

Without an Earth available, I'm all out of ideas though I'm afraid, sorry I couldn't help

[jpinx]

yea - well - I am not deeply immersed in the technology - I just wanted my TV to not get fried

All electronic devices running off mains AC have a power supply of some description - and it doesn't matter if that's in the form of a plug-pack or an internal power supply - they're all just as fundamentally susceptible to damage from spikes as each other...

Without an Earth available, I'm all out of ideas though I'm afraid, sorry I couldn't help

Ok - thanks - What about if I go and buy a roll of wire and run it to the waste ground behind and connect it to a 1 metre spike in the ground? What are my options then?

[IMHO]

yea - well - I am not deeply immersed in the technology - I just wanted my TV to not get fried

All electronic devices running off mains AC have a power supply of some description - and it doesn't matter if that's in the form of a plug-pack or an internal power supply - they're all just as fundamentally susceptible to damage from spikes as each other...

Without an Earth available, I'm all out of ideas though I'm afraid, sorry I couldn't help

Ok - thanks - What about if I go and buy a roll of wire and run it to the waste ground behind and connect it to a 1 metre spike in the ground? What are my options then?

Well, in that case a couple of options:

1) A simple spike arresting power board or similar

or

2) An isolated + regulated power supply

The first is fine if the spikes are very short in nature (i.e in the millisecond range), and the supply voltage is otherwise stable.

If there's a lot of voltage swing or possibility of sustained high voltages for seconds or more, I would always recommend the 2nd option.

Given your description of "jumping fans" it sure sounds like there's some serious high voltage spikes going on there, so I would go regulated if it were my devices being protected...

[Pib]

If I'm at home and the power goes off or a brownout condition occurs, I start flipping my circuit breakers to off because I want to try to avoid the in-surge of current or reduced brownout voltages...that places a real strain on electronics/electrics...and it can definitely make the ones with motors (fans, A/Cs, pumps, etc) jump!!! I also have a whole house surge protector installed and use surge protected power strips to plug my electronics into. I made/installed the whole house surge protector and also modified/upgraded the power strips to ensure I had 3 modes of surge protection...that is Line-Neutral, Line to Earth, and Neutral to Earth. The great majority of surge protector power strips you buy only come with surge protection on Line-Neutral...better than nothing, but it only provides one mode of protection for voltage spikes. I wouldn't recommend to anyone to make/design/modify surge protectors unless they have a good understanding of electronics/electrics and have modified/repaired electronic before.

Anyway, I live in western Bangkok and several times a year I will go through power-out or brown-out conditions. And once or twice a month it's not uncommon to have a momentary lost of power (like less than a second) as the power company is apparently balancing/switching loads around my part of Bangkok....you don't have enough time to do anything during such brief events but no doubt it causes some healthy voltage spikes.

Sure, many electronics have been designed to better deal with surges/brownouts, but such conditions are not what the devices normally operates at/likes to see. I have installed an analog panel meter on the input side of my circuit breaker main panel unit so I can easily and quickly see what the voltage level is doing. I've watched it numerous times during power outages and brownouts and the voltage can easily vary from approx 20V to 200V before the power problem is truly solved and it becomes a rock steady 220V on the panel meter. If the voltage is too low/unstable, I turn off circuit breakers (to included the main circuit breaker) off until the power problem is fixed....when the problem is fixed I switch back on the main circuit breaker and then the individual circuit breakers one-by-one to prevent hitting the whole house/all circuits at once with one big surge.

I particularly hate brownout conditions where the 220V drops to something significantly lower, like 100 to 180V. Although many electronics nowdays are designed to work from approx 90 to 240 VAC it can still place strain on the electronics as it switches between 120V and 220V operations. Plus power spikes on a steady 220V don't do electronics any good....it stresses them....it can just slowly kill some...it might take years...or it might just take days...even with surge protection built-in...depends on the quality of the design.

This Link gives a nice little explanation of power surges/brownouts...it's talking 120V operations probably in the U.S...but just double the numbers to related it to 220V operations in Thailand.

Edited December 24, 2012 by Pib

[BigBabyJesus]

Down load the following PDF file http://surgelogic.co...01Rev0812.pdf , go to page 11 the surge supressors listed here are very good and will protect your whole house.

Single phas you need 1

3 phase you need 3

You will need 2 spare pole spaces in your breaker panel for each device. If you don't have the spare spaces there is a adapter which allows for external mounting.

We have installed these devices on over 60 locations and with the exception of a location have had no problems with large spikes or surges.

The exception was a surge that originated inside the houses electrical system.

They are designed to take care of large surges, the ones that blow everything up.

They are fairly easy to install, but I suggest a Qualified Electrician do the job, and that he follows the installation instructions EXACTLY.

Nothing will protect agianst a close direct lightning strike, but this device will take care of 99%.

Read and follow the instructions carefully.

You can download a excellent PDF document that is very informative http://surgelogic.co...9701Rev0812.pdf

Look at page 11 , these are the devices we use on a regular basis, and they are readably avaliable here in Thailand.

The PDF download is very informative and has wiring diagrams also.

For sensitive devices I still suggest a good UPS with a surge suppressor we use APC http://www.apcth.com/ agian never a problem.

If you have a adsl or dail up internet connection, we find that most of the computer that fail are due to the voltage surge comming in on the telephone line (conductive coupling of a electrical surge dur to the phone line being in close proximity to an electrical wire)

The UPS's have a surge supressor built in to protect agianst most of the phone line voltage spikes, UES IT! Read the manual and be sure to install the phone jacks in the proper place.

Remember "Safety is NO Accident"

Ksamuiguy,

I seek to install "whole house" surge protection in the house I am building. I prefer Type 1, but it is hard to find. I looked with interest at the Schneider "Surgelogic.com" catalogue you posted. Problem is, that catalogue is for the North American market, whose electrical system is not the same as here.

By the way, three phase is not available where I live. What we have is single phase, 220V, 50hZ, two wire (line & neutral), with third ground wire to earthed rod.

I looked at the Schneider catalogue for Thailand and the highest level of protection I could fins was the Type 2 QO-SPD225 (equivalent to the north American QO2175SB from p. 11 of your catalogue), but the level of protection is significantly below what I seek. In your catalogue, the product I like is the Schneider SDSB1175B, which, as I said, is for the North American (split phase) market.

Do you know of any comparable device available or that will work here? Do you have a model number? If you have this information, it would be very helpful. This problem has been driving me nuts.

Surely there must be a device available for Thailand that offers more than 15kA (QO-SDD225) of surge protection? I sure would like to find and source it.

[BigBabyJesus]

If I'm at home and the power goes off or a brownout condition occurs, I start flipping my circuit breakers to off because I want to try to avoid the in-surge of current or reduced brownout voltages...that places a real strain on electronics/electrics...and it can definitely make the ones with motors (fans, A/Cs, pumps, etc) jump!!! I also have a whole house surge protector installed and use surge protected power strips to plug my electronics into. I made/installed the whole house surge protector and also modified/upgraded the power strips to ensure I had 3 modes of surge protection...that is Line-Neutral, Line to Earth, and Neutral to Earth. The great majority of surge protector power strips you buy only come with surge protection on Line-Neutral...better than nothing, but it only provides one mode of protection for voltage spikes. I wouldn't recommend to anyone to make/design/modify surge protectors unless they have a good understanding of electronics/electrics and have modified/repaired electronic before.

Anyway, I live in western Bangkok and several times a year I will go through power-out or brown-out conditions. And once or twice a month it's not uncommon to have a momentary lost of power (like less than a second) as the power company is apparently balancing/switching loads around my part of Bangkok....you don't have enough time to do anything during such brief events but no doubt it causes some healthy voltage spikes.

Sure, many electronics have been designed to better deal with surges/brownouts, but such conditions are not what the devices normally operates at/likes to see. I have installed an analog panel meter on the input side of my circuit breaker main panel unit so I can easily and quickly see what the voltage level is doing. I've watched it numerous times during power outages and brownouts and the voltage can easily vary from approx 20V to 200V before the power problem is truly solved and it becomes a rock steady 220V on the panel meter. If the voltage is too low/unstable, I turn off circuit breakers (to included the main circuit breaker) off until the power problem is fixed....when the problem is fixed I switch back on the main circuit breaker and then the individual circuit breakers one-by-one to prevent hitting the whole house/all circuits at once with one big surge.

I particularly hate brownout conditions where the 220V drops to something significantly lower, like 100 to 180V. Although many electronics nowdays are designed to work from approx 90 to 240 VAC it can still place strain on the electronics as it switches between 120V and 220V operations. Plus power spikes on a steady 220V don't do electronics any good....it stresses them....it can just slowly kill some...it might take years...or it might just take days...even with surge protection built-in...depends on the quality of the design.

This Link gives a nice little explanation of power surges/brownouts...it's talking 120V operations probably in the U.S...but just double the numbers to related it to 220V operations in Thailand.

\

Pib,

You have whole house surge protection? Exactly what make and model are you using. I am having a tough time sourcing a decent unit in this country. Thanks!

[Pib]

Pib,

You have whole house surge protection? Exactly what make and model are you using. I am having a tough time sourcing a decent unit in this country. Thanks!

Model number is: PIB. That is, as mentioned it's home made. I bought all the necessary individual parts like the varistors, thermal fuses, terminal connectors, indicator lights, housing box, etc.., and then assembled and installed it myself. Probably at least 10 times cheaper than buying one.

Edited December 24, 2012 by Pib

[DekDaeng]

I have seen many cases where the lightning struck phonelines and killed everything from modem / router / switch / network ports and so on.

Indeed. Another advantage of "fibre to the home" broadband, if you can get it.

Running wi fi instead of ethernet provides protection for computer etc etc, in case of lightning strike on the phone line. But modem & router likely toast.

Use a UPS for the computer power line.

[DekDaeng]

Pib,

You have whole house surge protection? Exactly what make and model are you using. I am having a tough time sourcing a decent unit in this country. Thanks!

Model number is: PIB. That is, as mentioned it's home made. I bought all the necessary individual parts like the varistors, thermal fuses, terminal connectors, indicator lights, housing box, etc.., and then assembled and installed it myself. Probably at least 10 times cheaper than buying one.

PIB, what are the chances of an 'ible'? (Instructable)?

[Pib]

Pib,

You have whole house surge protection? Exactly what make and model are you using. I am having a tough time sourcing a decent unit in this country. Thanks!

Model number is: PIB. That is, as mentioned it's home made. I bought all the necessary individual parts like the varistors, thermal fuses, terminal connectors, indicator lights, housing box, etc.., and then assembled and installed it myself. Probably at least 10 times cheaper than buying one.

PIB, what are the chances of an 'ible'? (Instructable)?

Nope, better not...playing with line voltage can be dangerous for many.

[westom]

Do you know of any comparable device available or that will work here? Do you have a model number? If you have this information, it would be very helpful. This problem has been driving me nuts.

Facts, numbers, and sources that define effective protection. Lightning is typically 20,000 amps. A minimal 'whole house' protector must conduct at least 50,000 amps and to earth. A protector must meet or exceed that number to remain functional after every surge - including the direct lightning strike. Because protection has always been about direct strikes without damage. And has always been about what the protector connects to.

More responsible manufacturers provide these solutions. Including ABB, Schneider, General Electric, Clipsal, Novaris, Siemens, Keison, Polyphaser, and Eaton to name only a few. Often available at every electrical supply house.

Now, what does protection? A protector never does protection. A protector is only a connecting device. It must connect low impedance (ie 'less than 3 meters') to what *absorbs* hundred of thousands of joules. Only effective protectors have a dedicated wire for the always required 'low impedance' connection to single point earth ground.

Attention focuses on the only item that must always exist in every protection system. Some systems have no protectors. But every protection system always - without exceptions - has the essential earth ground. Hundreds of thousands of joules must be absorbed somewhere in a protection system. Earth ground and a low impedance (ie 'less than 3 meter') connection to earth is essential. Effective protectors always have a separate and dedicated wire to connect hundreds of thousands of joules to earth. Protectors without that short connection do not even claim to protect from a typically destructive surge. Every effective protection system always has a short connection to single point earth ground.

Defined are numbers (ie 50,000 amps), responsible manufacturers that actually provide solutions, and what every protector must connect to (earth ground). Three requirements that summarize actual protection. And ignored by UPS recommendations. Where does even one UPS recommendation provide critical numbers? No numbers is a first indication of urban myth and bogus recommendatoins. A minimal 'whole house' protector starts at 50,000 amps.

Edited December 24, 2012 by westom

[Pib]

And for the electronics/electrics layman out who there might think weston's post above stating figures of 20,000 amps, 50,000 amps must not be correct as that would blow up a rock, well, he talking that amount of amerage in the power surge lasting for only micro to milli seconds....not continuous like your rice cooker drawing X-amps for 30 minutes. A very brief pulse of energy where the width/length of time of the pulse is a player in calculating amps in reference to duty cycle, peak amps, continuous amps, etc....all that technical stuff. While indeed EXTREMELY high amps for a very brief time, but when calcuations are done to convert that to the equivalent continuous amps it calculates to a low continuous amperage amount therefore simple/inexpensive electronics components exist which can handle this pulsed energy for milli/micro seconds.

Most whole house surge protectors, surge protected power strips, surge protector module that plug into your circuit panel box, etc., have primarily one key component which is responsible for the surge protection...and that called a "varistor." Actually, in a whole house surge protector there will probably be several to a dozen or so hooked up in parallel to increase their total power/amps handling capability. Like shown in the image of an Eaton whole house protector shown at the bottom of this post.

A varistor is nothing more than a device that quickly starts conducting at a certain voltage and as the voltage gets higher it fully conducts and reaches the "shorted" stage where it pretty much coducting like a piece of wire....as the voltage goes back down it stops conducting and appears as an open circuit again. This whole process from the start of the surge to its end and the start of the varistor conducing/shorting to not conducting/returning to a open circuit occurs over micro to milli seconds. Now if it does last a few seconds like due to power lines shorting out due to a tree falling on the lines vs a very brief voltage spike caused by lightning or a high current device being turned on, that could easily damage/smoke the surge protector.

Usually the varistors used in residential surge protectors a physically about the size of "one baht coin" or smaller...a 20mm varistor typically used is physically the size of a one baht coin...and a 7mm varistor about the size of a 25 stang coin. A 20mm varistor costs less than 10 baht and a 7mm varistor even less...but by the time they are manufactured in a whole house protector you effectively pay about a 100 times higher amount--gotta make that profit. When I bought my EPOCS 20mm 275VAC varistors locally to build my whole house surge protector and to modify/upgrade my surge protector strips they cost me around 6 baht a peice. The 275VAC figure means it can operate continuously up to 275VAC (gives you a safety cushion in case you line voltage goes significantly above 220V for several seconds or even continuously, it will start conducting a small amount when a surge/spike reaches approx 430V Peak and be fully conducting (acting like a short) at approx 710V Peak...which means hopefully any voltage spike will be clamped to 710V max which most electronics can safely handle for a very brief period. They are also rated at 8,000 amp (remember pulsed amps)....put 2 in parallel and you have 16,000 amps surge handling capability, 3 in parallel 24,000 amp, etc...etc...etc. In my setup I put 6 varisters in parallel to have 48,000 amp per mode (L-N, L-E, N-E) or 144,000 amp total....however, but, in accordance with rating standards used by surge protector manufacturers you don't count the N-E amount for the surge protector's overall amp rating...you only count the L-N ad L-E...so my whole house surge protector has a rating of 96,000 amp.

Everything I've read seems to say the max you can expect to enter your home service electrical entrance like from a very nearby lightning strike on the power lines is 10,000 amps. Yes, lightning can consist of millions of voltage and maybe millions of amps, but it is quickly attneuated/reduced once it strikes an object. But you want a surge protector rating higher than 10,000 amps in order for the varistors in the protector to last a long time...each big surge takes a toll on the varistors....plus if you were super unlucky in a lightning storm and you have repeated lightning strikes really close to your home you don't want a whole house surge protector rated to only handle one 10,000 amp unlucky surge....it would protect you on that first lightning strike and maybe a few more but then it's been stressed too many times close to its max rating it could fail leaving you with no protection and maybe some smoke coming from the surge protector box. A person should probably get a whole house protector rated for at least 25,000 amp...personally I would go for at least 40,000 amps. You sell them sold at much higher rating but that's only because manufactures know people think the more is better...well, you reach a point to where more don't add any benefit to the customer but does add to the manufacturers sales and profits.

Remember we are talking about micro/milli second pulses/spikes/surges; not continous events. Also, the varistors that I've seen (removed) from power strips usually start at around 330VAC which offer less surge protection (and cheaper to make) because it take a higher surge/spike amount to make them start conducting....or said another way, provides less surge protection as smaller surges won't be suppressed.

Picture of Typical Varistors

Pictures of typical varistors in a Eaton Whole House Surge Protector (varistor connected in parallel to increase surge rating)