Recent surges have zapped three Masterplug Suregards and a PC PSU, despite the latter being plugged into a Sureguard. The PSU fuse didn't blow, of course.
Unfortunately, I hadn't registered the Sureguards when I bought them, so I probably can't claim. Has anyone here ever claimed from Masterplug?
Is there any way to repair them, especially as they were 20 quid each from Screwfix. Item number 25276, no longer stocked.
Cue whiskey tango oscar mike!
He's not as reliable these days, but I.m not putting any money on him not posting ;-)
Sounds like a SmartUPS might be "cheaper" :-)
If you'd not had the 'surge protectors' you'd only have lost the pc psu, less money gone.
FWIW a pc psu has better surge protection than a plugin 'surge protector' Unless you're running off a small genny or very prone to lightning strikes theyre pretty worthless
NT
Not that simple. 3 SPs zapped. SP1: PC OK. SP2: PSU dead. SP3: TV, sat rcvr, sky+ box, home cinema all OK.
Are you thinking the surge protectors saved the other 2? Its very unlikely.
NT
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Peter Twydell saying something like:
Most of these crappy surge protectors rely on an MOV [1], which typically costs around 20p to replace. They degrade in service and give no indication they've nothing left to give when a surge strikes, so in effect you are unprotected after x period of time. Frankly, I'd buy a Smart-UPS or similar and perhaps surge-protect the output of that for anything that gets through it.
[1]
NT
Plug-in protectors are often so grossly undersized that a surge, unable to overwhelm protection inside an appliance, easily destroys the protector. In your case, the surge was apparently even larger.
No protector provides protection. Grasp that sentence because it is so difficult for so many to understand. A protector does not do protection. A projector is only a connecting device to what provides protection. Plug-in protectors do not make that connection. Plug-in protectors are mostly profit centers.
For over 100 years, surge protection has always been about where energy dissipates. Either energy dissipates harmlessly in earth. Or that energy is inside hunting for earth ground destructively via some appliance. You have seen same.
Either a protector makes a short (ie 'less than 3 meter') connection to earth. Or, it gives a surge even more paths destructively via appliances. Power strip or UPS - same thing. Neither claim protection in their manufacturer numeric specs.
No protector is protection. A protector too close to appliances can even make damage easier. How does BT suffer maybe 100 surges with each thunderstorm - and no damage? Clearly they disconnect telephone service during every storm - what some must assume based upon their posts. Reality. BT connects every incoming wire in every cable as short as possible (ie 'less than 3 meters') to single point earth ground. Either directly or via a protector. And locates protectors up to 50 meters distant from electronics. Increased distance - separation - means protection is even better.
You need same. Keison is just one example of well proven technology
- what has been standard for over 100 years. Neither those power strip nor UPS even claim to provide protection. And have massive profit margins. Energy that does not enter the building does not hunt for earth destructively via appliances. Somehow that power strip or UPS was going to stop what three miles of sky could not? That is what others have claimed.
You were wise...he has reared his ulgly head...
I think a lot of the mythology surrounding surge protectors comes from confusion over the word 'surge.' Surge protectors are not designed to withstand lightning strikes - even a piece of unobtanium couldnt do that. What they do protect against is surges caused by inductive loads, ie surges of a couple of hundred volts. And then only occasional ones, if theyre frequent the varistor deteriorates and becomes ineffective.
As Tom rightly says they're an easy profit line, you can sell a 4 way adaptor for several times the price if you put a useless 50p varistor in it. Throw in some sales spew that does nothing to dispel the confusion over what types of surge it doesnt and doesnt protect against and you've got an easy money spinner.
The reality is that the filter in any PC PSU has more surge protecting ability than any plug in surge protector can possibly have. Why? The psu has series, parallel and energy storage elements. The surge protector has only a parallel element, and it isnt anywhere near as effective without the other 2 bits.
So yes, theyre a mugs game.
And finally... do we need them? In short no, not a bit, but I've got other things to go do now.
NT
The best information on surges and surge protection I have seen is at:
- "How to protect your house and its contents from lightning: IEEE guide for surge protection of equipment connected to AC power and communication circuits" published by the IEEE in 2005 (the IEEE is the major organization of electrical and electronic engineers in the US). And also:
- "NIST recommended practice guide: Surges Happen!: how to protect the appliances in your home" published by the US National Institute of Standards and Technology in 2001
The IEEE guide is aimed at those with some technical background. The NIST guide is aimed at the unwashed masses.
Both are written for the US, the UK differs mainly in earthing practice for power and telephone.
The author of the NIST guide has many published papers on surge protection. One of them looked at the energy that is absorbed in a plug-in suppressor on 10-50 meter circuits. The surge current coming in on the power wire was 2000A up to the maximum that has any probability for even a very close lightning strike. The energy absorbed by the suppressor MOV was surprisingly small - 35 J max. In most cases it was
1 J or less. That was based on US power systems, which have better earthing for surges than some systems in the UK. But a major factor was the impedance of the wiring. Surges are a short duration event, thus have relatively high frequency current components, thus the inductance of the wiring greatly limits the current that can reach the suppressor.And plug-in suppressors with high ratings are readily available.
In the US, suppressors are required to disconnect failing MOVs - probably also in the UK. The IEEE guide describes at length how connected equipment can be connected across the MOV so it is disconnected if MOVs fail, or connected to the incoming power wires. In the first case, connected equipment is protected even if MOVs fail.
Some plug-in suppressors have warranties for connected equipment. They can have warranties because a quality suppressor, connected as the manufacturer shows, is not likely to fail (and if it does the protected equipment is disconnected with the MOV). The are likely to provide protection even from rather very lightning strikes.
w has a religious belief (immune from challenge) that surge protection must directly use earthing. Thus in his view plug-in suppressors (which are not well earthed) can not possibly work. The IEEE guide explains plug-in suppressors work by CLAMPING (limiting) the voltage on all wires (signal and power) to the common ground at the suppressor. Plug-in suppressors do not work primarily by earthing (or stopping or absorbing). The guide explains earthing occurs elsewhere. (Read the guide starting pdf page 40).
Some posters are either psychics or know w is evangelical in spreading his beliefs, and uses google groups to search for "surge" to convert the heathens.
Any quality suppressor will have MOVs from hot to neutral, hot to ground, neutral to ground.
The NIST guide cites US insurance information that indicates equipment most likely to be damaged by lightning is computers with modem connection and TV related equipment - with cable connection. All can be damaged by high voltage between signal and power wires. This is more of a problem in the UK since BT does not routinely clamp the voltage on phone wires to earth. (An example of high voltage between power and cable wires is in the IEEE guide example starting pdf page 40.)
As a result, all external wires, like phone, going to equipment connected to a suppressor need to go through the suppressor. Connecting all wiring through the suppressor prevents damaging voltages between power and signal wires. This will be required for any connected equipment warranty. These multiport suppressors are described in both guides.
Yup. Keison makes plug-in suppressors.
Complete nonsense. Some plug-in suppressors even have connected equipment warranties.
The UPS function of most consumer UPSs do not provide surge protection, but the same protection as in plug-in suppressors is usually added. High ratings are not as easy to find.
I would not connect a plug-in suppressor downstream from a UPS.
That is what w claims because his religious blinders don't allow him to understand how plug-in suppressors work.
The IEEE guide has 2 examples of surge protection. Both use plug-in suppressors. The NIST guide says plug-in suppressors are "the easiest solution" and "one effective solution is to have the consumer install" a multiport plug-in suppressor. Both guides indicate that properly connected plug-in suppressors with adequate ratings are one of the techniques that can be used to provide surge protection.
w's sources say .... nothing.
Probably the biggest difference between US and UK is the level of strike induced voltage surges. In the US it warrants protection, in the UK it usually doesnt.
they have warranties because even with no element in the warranty is an easy earner, and customers want the warranties.
I'm unclear where else you propose to dissipate 1000s of volts.
you're contradicting yourself, either they do or they dont clamp to earth.
Lets be honest here: if the mfrs were serious about surge protection they would use what every PC PSU uses to protect itself against surges, a pi filter arrangement, not just the parallel element found in surge protectors.
I believe it does - you'll find the GDTs in every BT master socket.
It cant possibly, the necessary energy absorption simply isnt there. A lightning strike can vapourise any material the size of a little MOV.
A related common mistake is to think that the equipment mfr's warranty is void if no surge absorber is used.
(from very near lightning strikes)
It doesn't earn anything if warranty payments are larger than what you make on sales. With the cost of modern TVs and audio systems, in particular, you have to sell a lot of suppressors to cover one warranty payout. If you have no local lightning there can still be damaging surges from normal and abnormal utility operation. (the NIST guide briefly covers "switching surges".) And suppressors with warranty *are* sold where there is major risk of surges from lightning.
I gave a little information (above in my first post) on a paper that looked at the energy absorbed in a MOV in a plug-in surge suppressor. The surges coming in on the power wire were up to 10,000A. That is the maximum that has any reasonable probability of occurring with even a very near strike. (It is based on a 200,000A strike to a utility pole behind a house with typical urban overhead distribution.)
As I wrote, the energy that is absorbed at the MOV was surprisingly small - 35 J max. In most cases it was 1 J or less. That is well within the ratings of any suppressor that is not junk.
There are a couple reasons for the surprisingly low energy. In US power systems, at the consumer unit the incoming utility neutral is always connected to "ground", and that combined connection is always connected to one or more earthing electrodes. When a large surge comes in on a power wire, when the voltage from a 'hot' bus to the enclosure reaches about 6,000V there is arc-over. When the arc is established the voltage is hundreds of volts. Since the enclosure is connected to an earthing electrode, that dumps most of the surge energy to earth. Since the neutral is connected to the enclosure, the maximum hot to neutral (and "ground") voltage is about 6,000V maximum.. In the UK, the arc-over voltage may be different from 6,000V but shouldn't be radically different. You have several different neutral and earthing configurations. (In addition, in the US at about 6,000V there is arc-over in sockets.)
The other reason the energy is so small is that, as I wrote above, a surge is high frequency current components and the inductance of the wire from the consumer unit to the plug-in surge suppressor greatly limits the amount of current that can reach the MOV. (The impedance of the "ground" wire from a plug-in suppressor is why w says plug-in suppressors don't work.)
There is no contradiction because I never said plug-in suppressors clamp to "earth". Read it above - the voltage on all wires is clamped to the _common ground at the suppressor_. The voltage between the wires going to the protected equipment is safe for the protected equipment.
Read the example in the IEEE guide starting pdf page 40. Or read the whole guide - you might learn something.
Lets be honest here. A filter can reduce the rise time. A reasonably sized filter does not reduce the imposed voltage. (The filter capacitors on a PC power supply might.)
Neither the IEEE or NIST guides mention "filters" as an effective surge protection method.
The few PC power supplies I have looked at have MOVs.
And according to the IEEE guide, for power wires "the vast majority (>90%) of both hard-wired and plug-in protectors use MOVs to perform the voltage-limiting function. In most AC protectors, they are the only significant voltage limiters." MOVs are so widespread because they have high energy dissipation capacity in a small package at relatively low cost.
I have read posts from people in the UK that say master sockets clamp the voltage between the phone lines but seldom clamp to an earth connection. One comment was that earthing was "a practice that the GPO (forerunner to British Telecom) abandoned in the 1960s"
To be effective the wires to common connections for earthing between phone, power and cable have to be short. (The master socket has to be near the consumer unit.) It is in the example in the IEEE guide starting pdf page 40.
As I wrote in my original post and above, the energy isn't there for a plug-in suppressor.
The fact is some manufacturers offer connected equipment warranties and sell their suppressors in areas where there is significant risk of damage from lightning. If the suppressors did not work the manufacturers couldn't do that.
The energy *is* there in suppressors installed at consumer units. The MOVs in those suppressors don't vaporize either. Suppressor ratings are readily available well over the 10,000A maximum surge that has any reasonable probability of occurring in a house consumer unit power wire.
Responsible sources repeatedly say a protector must clamp (connect, divert, shunt, bond) to "earth". The NIST (US government research agency) is blunt about it. From Bud's NIST citation:
work by diverting the
No earth ground means the protector is what? I label it "ineffective". The NIST is even blunter. That protector without earth ground is "useless".
Bud is a sales promoter for plug-in protectors. He is paid to post reams of accusations, confusions, and myths. Even his own IEEE citation (page 42 figure 8) shows what happens when the protector is too close to appliances and too far from earth ground. A nearby TV is 8000 volts damaged. An example of what happens with a 'high profit' protector that does not even claim protection in its manufacturer specifications. A TV that is 8000 volts damaged because that protector is too far from earth ground and too close to electronics. The NIST says that protector without ground is "useless". Therefore high reliability facilities do not waste money on plug-in protectors. Effective protection means being fanatical about a short (ie 'less than 3 meter') connection from the 'whole house' protector to single point earth ground. A protector is only as effective as its earth ground.
Protection has always been about where energy dissipates. Plug-in promoters will not discuss energy to sell 'high profit' power strips. Effective protector costs about =A31 per protected appliance. A protector is only as effective as THE item that must absorb that energy - single point earth ground. Bud will post incessantly to obfuscate that reality. Where does energy harmlessly dissipate? 100 years of well proven science say why BT does not use his protectors. Why BT instead uses effective protectors that are within meters of earth ground - and up to 50 meters separated from electronics. All of Bud's citations say same. Say why his plug-in protectors are ineffective. Or as the NIST says: "useless".
they arent, clearly.
If I sold an empty cardboard box to clip over the wires plus an insurance policy for just one appliance and then for only one fault mode, and charged =A39 I'd make a profit.
But the only place the surge can usefully go is to eath. If it goes anywhere else the appiance is damaged.
US and UK are different when it comes to lighning strikes and protection against them. Our main feed here arcs at hundreds of volts, not 1000s. Testing appliances has shown me that lots of appliances arc over at between 1kV and 1.5kV.
Inductance cuts both ways. If it hampers the surge reaching the mov it also hampers it being diverted to earth.
either its clamped to the earth wire or the neutral, which is also at earth potential.
The flitering hugely reduces it, that's one of the points of it.
PC PSUs use
All these elements together ar outperform just one element.
minor risk, and wrong conclusoin
Lets look at some ballpark numbers. House insurance costs anything from =A3200 pa upward. How many appliances are there in the average home
- rough guess perhaps 50, and it may well be more. 50x=A39 =3D =A3450, and the plug-in surge protectors are only insuring against one single mode of appliance failure. Its easy money.
NT
by diverting the
What does the NIST guide really say about plug-in suppressors? They are "the easiest solution". And "one effective solution is to have the consumer install" a multiport plug-in suppressor.
With no valid technical arguments has to try to twist what the NIST guide says.
As explained in the IEEE guide, earthing occurs, just not primarily through a plug-in suppressor.
Anyone with half a brain who reads the NIST guide can see the guide says plug-in suppressors are effective.
To quote w "It is an old political trick. When facts cannot be challenged technically, then attack the messenger." My only association with surge protectors is I have some.
But with no valid technical arguments, w has to discredit those that oppose him.
If poor w could only read and think he could discover what the IEEE guide says in this example:
- A plug-in suppressor protects the TV connected to it.
- "To protect TV2, a second multiport protector located at TV2 is required."
- In the example a surge comes in on a cable service with the ground wire from cable entry ground block to the ground at the power service that is far too long. In that case the IEEE guide says "the only effective way of protecting the equipment is to use a multiport [plug-in] protector."
I don't think w has explained what he wants for protection. It is a suppressor installed at the consumer unit. That would provide absolutely NO protection in this case.
This is an IEEE example that shows how to provide protection with plug-in suppressors. With no valid technical arguments w has to try to twist what the IEEE guide says.
The required statement of religious belief in earthing.
Why aren't airplanes crashing daily when they get hit by lightning (or do they drag an earthing chain)?
The IEEE guide explains plug-in suppressors work by clamping the voltage on all wires (signal and power) to the common ground at the suppressor, not earthing. The guide explains earthing occurs elsewhere. (Read the guide starting pdf page 40).
w will post incessantly to protect his religious belief in earthing which is challenged by plug-in suppressors that do not work by earthing.
Mu reality comes from the IEEE and NIST guides - both excellent information. Both say plug-in suppressors are effective.
w's reality comes from his religious belief in earthing. Read w's sources that say plug-in suppressors are NOT effective - there are none.
Perhaps w could answer some simple questions:
- Why do the only 2 examples of protection in the IEEE guide use plug-in suppressors?
- Why does the NIST guide says plug-in suppressors are "the easiest solution"?
- Why does the NIST guide say "One effective solution is to have the consumer install" a multiport plug-in suppressor?
- How would a consumer unit suppressor provide any protection in the IEEE example, pdf page 42?
- Why does the IEEE guide say for distant service points "the only effective way of protecting the equipment is to use a multiport [plug-in] protector"?
Not if you had a warranty on connected equipment and paid out when that equipment was damaged. Certainly would be a looser where I live.
Not obvious what "one fault mode" is. Suppressors would warrant against surges coming in on power, phone or cable wires that go through the suppressor.
As I explained at length, there is a path to ground at the consumer unit. It is in the text just below.
(Not all surges go to earth. Utility transients may be hot to neutral.)
Are you saying that consumer units arc-over at "hundreds of volts"?
Electronics can be damaged at far below arc-over voltage. Internal MOVs may actually clamp the voltage to a reasonable level. With a large surge they may not. Plug-in suppressors with high ratings are readily available.
I am not, incidentally, advocating anyone use plug-in suppressors - I started by answering nonsense posted by w. There are several protection methods (read the IEEE guide). Or with low risk take your chances.
That is why the master socket needs to be near the consumer unit if the master socket has an earthing connection. And why the wire to an earthing electrode from the consumer unit/master socket should be short.
In the case of a plug-in suppressor - that is why w says they don't work. But they don't work the way w thinks they do - he can't understand the clear explanation in the IEEE guide.
At a plug-in suppressor the voltage on all wires (power and signal) is clamped to the earth wire. But if there is large surge current that earth wire connection at the suppressor is nowhere near earth potential. (clearly explained in the IEEE guide.)
A filter of reasonable size doesn't. Filter caps might as a snubber, but they are not designed to absorb a high current surge. Diodes might also die.
I have never read anything that says a filter is effective surge protection. Perhaps you could provide one.
The "IEEE Recommended Practice for Powering and Grounding Sensitive Electronic Equipment", a standard for protecting electronics, does not include filters as a surge protection device. MOV based suppressors are included. So are UPSs, but not the type consumers usually buy.
No one with half a brain would connect everything in a house to its own plug-in suppressor. They would be used only on high value equipment, and in particular equipment that is connected to both power and phone/cable
- that is the highest risk equipment according to the NIST guide. That would typically be TV/audio/entertainment centers. Also computers, not so much because of the cost of the equipment but the value of the data and hassle of creating a new setup. All of the TV related equipment would be connected to a single suppressor (as is clear in the examples in the IEEE guide).
Entertainment centers might be worth £4000 or more. I recently bought a multiport (with phone/cable feedthrough) plug-in suppressor with very high rating of 1770J total (90,000A) for about £45. In my opinion a good investment.
=EF=BF=BD450, and
I've not got all evening, and this bit above is the main point, and you at least seem to have missed it. The point is that home contents insurance insures against far more risk than a pile of surge suppressor sockets at a fraction of the price, ie as insurance policies, surge protectors are grossly overpriced. Therefore there is no need for them to do anything to be easy profit.
NT
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