Are mains surge protectors needed in the UK?

[JULIAN HALES]

That's not how lightning protectors work. They create a corona discharge
around the building, dissipating charge buildup immediately around the
site. That means that a strike is more likely to happen elsewhere.

The copper strap has a cross section of less than an inch, nowhere near
enough to safely shunt a real strike to earth. If the building does get
hit the strike will still do nearly as much damage as if it was not
there.

I know a Russian who was killed while rewiring his house, his name was Sergi

 

[AK]

Assumed is that lightning confronted everything inside the
house equally. Just not true. Based upon your description,
the circuit from cloud to earth borne charges found a good
path via those TVs. Therefore only TVs suffered a direct
lightning strike incoming and outgoing. Incoming and outgoing
are essential requirements for surge damage. If the computer
only had an incoming path and no outgoing path, then lightning
currents did not pass through nor damage computers. That
complete electrical path to earth ground is the essential
requirement for surge damage. Clearly other household
appliances did not make that same "complete electrical
circuit" connection; therefore were not damaged.

I don't really care about the Physics........all I know is that I wont take
the chance anymore

 

[Johannes H Andersen]

[...]

I've come to the conclusion that you must work for a maker of these
"whole house" surge protectors that you constantly advocate. Your
opinion is therefore biased, not objective, and worth **** all.

This explains w_tom's surge of mains FUD surge protector posts...

 

[Graham W]

Quite wise, IMHO.


You miss the point. If you have a lightning rod and a TV aerial on the
roof of a house, the lightning rod, even if it is higher than the
aerial, is not going to save your TV set from a direct strike. Your TV
will blow up regardless.

No, I haven't missed the point - what you say is right. It is just that
his faltering English is difficult to read and it makes more sense if
referred to the earth spike than a lightning conductor over the roof.
But he seems to mean the latter in what he has subsequently said.
I'll go away now! 8¬)

 

[VWWall]

There's no way of determining which path a lightning strike will take.
It depends much on the local electrical fields produced at the time. I
have seen lightning hit and destroy a tree, when much higher, better
conducting, structures were nearby.

That's not how lightning protectors work. They create a corona discharge
around the building, dissipating charge buildup immediately around the
site. That means that a strike is more likely to happen elsewhere.

The copper strap has a cross section of less than an inch, nowhere near
enough to safely shunt a real strike to earth. If the building does get
hit the strike will still do nearly as much damage as if it was not there.

True. I have worked on lightning protection schemes for the Cape
Canaveral Space Launch Facility. Not only is a direct hit a serious
problem but adjacent strikes can induce surges or electrostatic
discharges sufficient to destroy electronics. The idea is to construct
a sort of Faraday cage, which has corona discharge as well as giving
electrostatic protection. It's still an unsolved problem. The present
procedure is not to attempt a launch when there is a chance of storms.

A spacecraft ready for launch is completely isolated from any mains
power, so that form of "surge" protection is not needed.

Virg Wall

PS: A golfer, caught in a sudden lightning storm, raised his club above
his head. His companions shouted: Don't do that. Lightning will strike
your club!" His reply: "Even God can't hit a two iron!"

VWW

 

[Bernard Peek]

Are surge protectors on the main power supply actually needed in
the UK?

I've been running multiple home PCs in the UK for around 15 years and
have never had a problem with mains spikes, or ever heard from anyone
who has had a problem.

OTOH I've heard several reports of hardware losses in the US caused by
brownouts and spikes. The power distribution systems aren't as well
protected as in the UK, possibly because of the greater average distance
from substation to home, and poor earthing policies.

I've discussed internal wiring systems with US techies, some of them are
installing domestic wiring using uninsulated cables.

here in the UK we have few overhead mains power lines and have a
relatively steady mains power supply when compared to many other
countries (including the US).

However there seem to be very many surge protector products
advertised for sale in the UK (Argos, Maplins, etc).

I am quite sure it is not bad practice to use a surge protector but
in fact I have never known anyone who has has a problem from a
surge coming in through the power supply.

So personally I don't bother using a surge protector on my PC.

Am I being too complacent?

No.

I do have to report that I have recently had hardware damaged by 240v
power, but that was because the previous owner built a UPS system into
the garage and didn't mention it to the buyers. After blowing up some
kit I discovered that the garage supply does have lots of spikes, and a
square-wave waveform.

Ouch!

 

[Bernard Peek]

Concepts such as 'whole house' protectors and lightning rods
are long ago proven to be superior protection. Why? They
(unlike the ineffective plug-in protector) make a superior
connection to earth ground so that lightning does not find
earthing via TVs or computer.

That's not how lightning protectors work. They create a corona discharge
around the building, dissipating charge buildup immediately around the
site. That means that a strike is more likely to happen elsewhere.

The copper strap has a cross section of less than an inch, nowhere near
enough to safely shunt a real strike to earth. If the building does get
hit the strike will still do nearly as much damage as if it was not
there.

 

[w_tom]

Long before computers existed in homes, why were LED clocks
and radios replaced daily? Because switch generated
transients were and remain destructive? Why are RCDs and
dimmer switches - things more easily damaged and without any
external protection - also failing daily? Because again those
transients from switching are so destructive. Put some
numbers to those switch generated transients. Some who
promote utility switching as a source of destructive transient
never provide numbers and ignore those above real world
examples. They are promoting junk science made obvious by
their fear of numbers and a shortage of weekly examples. We
can see from dialy damaged electronics equipment that those
transients are so destructive.

You are replacing RCDs daily because of daily utility
switching and the resulting transients? We also don't put
umbrellas over that RCD because rain also does not damage the
RCD. Why install protection when sufficient protection
already exists?

Utilities are reconfiguring their grids every month for
maintenance, reconfiguring loads, and adjusting voltages.
Transients from such events can be seen sometimes as often as
daily. So where are all those damaged refrigerators?
Transients are well below what all appliance must be designed
to withstand without damage.

We install surge protection for a so destructive surge more
typically known as lightning. Other far less frequent events
do occur. Unfortunately some people confuse blackouts and
brownouts with surges. Surge protectors do nothing for a
blowing fuse or a utility line snapped by a construction
machine. Furthermore, destructive transients of all types
are made irrelevant by the less expensive and more effective
'whole house' protector.

 

[w_tom]

Somehow blackouts and brownouts are being confused with
destructive surges. The 'whole house' protector provides
protection from all types of surge. Plug-in protectors don't
even claim to provide equivalent protection. Blackouts,
brownouts, noise, and harmonic are not surges AND plug-in
protectors don't even claim to protect from them.

But let's assume a nearby heavy machine is creating frequent
transients every day. That plug-in protector is typically so
undersized that it is degraded within week or month end.
Review datasheets from MOV manufacturers for life expectancy
charts. They are selling devices for infrequent and more
destructive events. Furthermore, many plug-in manufacturers
grossly undersized internal components. How would you know?
Manufacturer even fails to discuss life expectancy. So again,
the plug-in protector still does not provide effective
protection.

 

[Mike Tomlinson]

Surge protectors (be they capacitors, varistors, or anything else) must
absorb the energy they're dealing with.

They don't work like that, Michael. Surge protectors use devices called
MOVs (metal oxide varistors) which conduct when the voltage across them
exceeds a predefined amount. So if you have a MOV between phase (live)
and earth, most of the time it sits there doing not a lot. When a surge
(spike) occurs on the phase wire, the device conducts and dumps the
excess onto the earth wire.

It's worth mentioning that most good quality power supplies used in PC
and related equipment has one or more MOVs built-in; however, extra
(external) protection does no harm.

As a belt-and-braces approach, surge protection in UK/Europe includes a
MOV between phase and earth, neutral and earth, and between phase and
neutral. This works because earthing was installed from the word go in
all but the very earliest electrical installations.

In the US, however, there are many existing legal, serviceable
electrical installations which have no effective earthing (i.e. are
phase and neutral only), so the makers of surge protection devices have
to dump surges from phase to neutral. They can't connect MOVs from
phase to the earth pin or from neutral to the earth pin, because if a
user has plugged the protector into a non-earthed outlet, there is a
danger that a surge could cause the MOV to conduct and raise the metal
casing of any device plugged into the protector to a lethal potential
without any adequate earth connection existing for it to dissipate to.
This would be an, um, "interesting" experience for anyone happening to
be in contact with said equipment at the time.

I would expect a suitable Uninterruptible Power Supply to provide
reasonable lightning protection

Yes, but I'd use the term "surge protection". Lightning protection is
dealt with outside the building by way of lightning rods, etc. and even
then is very much an act of God in the event of a nearby or direct
strike.

Obviously there are differences between a building in the middle of a
city and a house on a lone mountaintop!

Tell me about it. We have construction (a metal enclosure) on top of a
mountain 8000 feet up in the Canary Islands. Total protection against
lightning strikes is, realistically, out of the question, but we have
attempted to install a reasonable system. Standing advice, however, is
to abandon site in the event of a thunderstorm. Perhaps w_tom would
care to test the system out for us during the next major storm

 

[Ken]

However.....

modems are different. If the strike hits a telephone pole then the
resulting surge down the phone line can easily take out a modem,
and if you're unlucky your mobo as well. Usually though your modem
will act as a very expensive fuse.

I use my own home made over voltage arrestors for my telephone line
http://w1.857.telia.com/~u85710476/docs/image/drawings/blixtskydd_tel_1.png
(swedish) I use one set at the incoming of the line,
and another set near my ADSL modem and computer.

This week we have a thunderstorm and my fuses blown,
se the blown fuses here
http://w1.857.telia.com/~u85710476/docs/image/example/fuse.jpg

My over voltage arrestors works very well. This is the fourth time.

 

[Mike Tomlinson]

Your reputation would be much enhanced and your posts would be far more
legible if you stopped top-posting and replied to each point raised,
quoting context, instead of rambling in a long, top-posted, hand-waving
rant.

Furthermore, many plug-in manufacturers
grossly undersized internal components. How would you know?

Many good quality European surge protectors illuminate a warning lamp to
indicate when the protective devices have degraded such that they are no
longer effective and that the protector should be replaced. Some,
including Belkin devices, also illuminate a lamp to indicate that the
protector has been connected to an outlet with a good earth.

Given that you in the USA tend to use for your electrical accessories
the cheapest and nastiest shit from China, it comes as no surprise that
your "surge protectors" do not carry even this basic feature.

So again,
the plug-in protector still does not provide effective
protection.

Complete crap. As usual.

 

[Ken]

http://w1.857.telia.com/~u85710886/docs/image/highres/hr_transient_11.jpgOn

However.....

modems are different. If the strike hits a telephone pole then the
resulting surge down the phone line can easily take out a modem,
and if you're unlucky your mobo as well. Usually though your modem
will act as a very expensive fuse.

I use my own home made over voltage arrestors for my telephone line
http://w1.857.telia.com/~u85710476/docs/image/drawings/blixtskydd_tel_1.png
(swedish) I use one set at the incoming of the line,
and another set near my ADSL modem and computer.
My telephone lines are buried in the ground the hole way (750 meters)
from the telephone station to my home.
This week we have a thunderstorm and my fuses blown,
se the blown fuses here
http://w1.857.telia.com/~u85710476/docs/image/example/fuse.jpg
My over voltage arrestors works very well. This is the fourth time.
This is a double line model I built myself
http://w1.857.telia.com/~u85710886/docs/image/highres/hr_transient_11.jpg

 

[w_tom]

I would expect this myth from Mike Tomlinson who even makes
wild speculations about how electrical systems are wired.
Bernard, don't promote myths from the Early Streamer Emission
(ESE) industry. Some had even tried to sue the National Fire
Protection Association (to bankrupt it) because NFPA rejected
their ESE speculations. Lightning rods do not and never did
"dissipating charge buildup" making "a strike is more likely
to happen elsewhere". Yes the ESE industry tries repeatedly
to make that claim but forgets to do one simple thing -
provide supporting facts and evidence. They instead uses
classic junk science. In fact, one ESE device was blown off
the roof of an airport control tower the week it was installed
- by lightning. How can this be? Dr Abdul Mousa demonstrated
that silly ESE claim in a paper in the IEEE Transactions on
Power Delivery on October 1998.

Please don't continue to promote the myth that lightning
rods provide "corona discharge around the building,
dissipating charge buildup immediately around the site". That
is simply classic junk science. Dr Mousa cites in his paper,
"theoretical and field studies which were commissioned by the
Office of Naval Research, the US Air Force, NASA, and the
FAA". He then says, "The invalidity of the concept of
lightning elimination has since been confirmed by other field
studies."

Furthermore we have direct from the US Army's Training
manual TM5-690 the size a wire must be to earth a direct
strike:

http://www.usace.army.mil/inet/usace-docs/armytm/tm5-690/c-3.pdf
is 14 AWG copper, 12 AWG aluminum, or 1 inch wide solid
strip. Again it is nothing short of speculation that massive
conductors are required to earth lightning. But speculation
has been widespread and challenged in this thread. Cited by
this author here and elsewhere are numbers from those who
actually do the work. I wish Mike Tomlinson understood the
concept better. Then he would not have to resort to personal
insults to make his claims.

 

[w_tom]

Protection from the most lightning prone locations is
routine and well understood. Others who have been in Mike's
Canary Island situation say "no problem":
http://www.telebyteusa.com/primer/ch6.htm
See Section 6.4: WHEN SHOULD YOU WORRY ABOUT LIGHTNING?

Conceptually, lightning protection devices are switches to
ground. Once a threatening surge is detected, a lightning
protection device grounds the incoming signal connection
point of the equipment being protected. Thus, redirecting
the threatening surge on a path-of-least resistance
(impedance) to ground where it is absorbed.
Any lightning protection device must be composed of two
"subsystems," a switch which is essentially some type of
switching circuitry and a good ground connection-to allow
dissipation of the surge energy.

It defines both the single point earth ground and a
connection to that ground - surge protectors or hardwire.
Curious. They did exactly what I have demonstrated.

http://www.harvardrepeater.org/news/lightning.html

Well I assert, from personal and broadcast experience
spanning 30 years, that you can design a system that
will handle *direct lightning strikes* on a routine
basis. It takes some planning and careful layout, but
it's not hard, nor is it overly expensive. At WXIA-TV,
my other job, we take direct lightning strikes nearly
every time there's a thunderstorm. Our downtime from
such strikes is almost non-existant. The last time we
went down from a strike, it was due to a strike on the
power company's lines knocking *them* out, ...
Since my disasterous strike, I've been campaigning
vigorously to educate amateurs that you *can* avoid
damage from direct strikes. The belief that there's
no protection from direct strike damage is *myth*. ...
The keys to effective lightning protection are
surprisingly simple, and surprisingly less than
obvious. Of course you *must* have a single point
ground system that eliminates all ground loops. And
you must present a low *impedance* path for the energy
to go. That's most generally a low *inductance* path
rather than just a low ohm DC path.
http://lists.contesting.com/_towertalk/1997-April/004413.html
The basic scenario is to install a Single Point Ground
System that is installed at the building entry. It shunts
everything to ground before it goes in the building. If
you can keep it outside, then you don't really have to do
much inside. IMO disconnecting the cables is more
psychological than preventive.
http://scott-inc.com/html/ufer.htm
The land owner warned us that this tower was frequently
struck, and equipment had been repeatedly damaged despite
increased precautions. Indeed, during July construction,
the masonry workers left the site after "a bolt sent
fireballs rolling down the [existing] tower". With a
sensitive CMOS controlled transmitter and a talking remote
control selected for the installation, I knew that any
transient overvoltage protection devices I would specify
would need a very conductive path to ground to divert
strike energy away from the equipment. ...
In sixteen months, the site has maintained twenty-four hour
per day operation with ZERO downtime except due to AC power
failure. With equipment so susceptible to transients, this
kind of performance is unusual in this region, especially
on this hill.

Mike would have us believe that an inferior US electrical
distribution system creates surge damage in the US. He
forgets that the UK has almost no lightning compared to the US
and still suffered significant damage. Especially true was
the amount of modem damage in the UK during an unusual
thunderstorm on 4 July 2004. Trivial storm by American
standards. Numerous UK modems were unnecessarily damaged due
to no properly earthed protectors.

Plug-in protectors in the US are three wire. Makes no
difference. A distance of much more than 3 meters (10 feet)
to earth ground means the plug-in protector is not earthed -
as demonstrated by previously posted numbers that remain
unchallenged. Excessive wire impedance from wall receptacle
to earth ground explains why plug-in protectors are so
ineffective, why the manufacturer does not even claim to
protect from the destructive type of surge, and why Mike
Tomlinson assumes a certain amount of surge damage is
acceptable. To maintain a myth about plug-in protection, he
must ignore the numbers. How then does he deal with testimony
from industry professionals who have learned concepts of
effective protection and don't suffer damage. How does he
explain 25 direct strikes per year to electronics atop the
Empire State Building without damage? A surge protector is
only as effective as its earth ground.

In the meantime, does not matter whether the US has two
prong or three prong receptacles. Important ground for surge
protection is located at the breaker box. Effective if that
ground meets or exceed post 1990 NEC requirements with a less
than 10 foot (3 meter) connection - to create a low impedance
connection. Low impedance as so many above industry
professional demand. Again wire impedance makes it obvious
why that earthing distance must be so short. Mike ignores
that basic electrical principle to hype his mythical plug-in
protection.

The UK does not even provide effective earthing at every
incoming phone line on every customer premise. Then when
damage occurs, Mike will tell us that surge protection can
never be effective. What a defeatist attitude! I guess those
industry professionals who deal with real world protection
must all be wrong. They have frequent direct strikes and
still don't suffer damage. Electronic equipment atop the WTC
was struck on average 40 times per years - again without
damage. In fact most strikes there went unnoticed. Why is
damage acceptable to Mike in the Canary Islands?

BTW, Mike forgot to mention that most good power supplies
have 2000 volts galvanic isolation which is why computers
already have effective internal protection. Protection that
is not overwhelmed if incoming transients be earthed at the
service entrance by a one effective and properly earthed
'whole house' protector.

Mike does not even challenge the excessive wire impedance
from a wall receptacle to earth ground. Better to ignore the
fact that he cannot challenge.

 

[w_tom]

It does not matter whether you top post or bottom post.
Your repeated intolerance is demonstrated both by your
difficult to read bottom posts, your need to pervert others to
your inferior posting method, your repeated intolerance to
those who disagree with your unsubstantiated opinions, and the
fact that you still cannot challenge technical facts - and
must then insult. BTW I still have not returned to you some
of your very first words. Let me start with one you posted to
me in your very first post - you twit.

I have posted as professional papers and technical
application notes are posted. New information up front.
Background information and references at the end. I am not so
intolerant as to bring up the silly top post / bottom post
nonsense that only the emotional would do.

You reputation would be enhanced if you could even challenge
the post demonstrating wire impedance. You cannot. So
instead you again start this silly top post / bottom post
nonsense. Do you like it when someone attacks you as you
attack others - by questioning your character?

Back to technical fact. And this makes it obvious how
little you know about surge protectors. In scary pictures are
more expensive surge protectors even with the MOVs removed -
and the "Protection Working" LED says protector still works
OK. How? Why? Why is the "OK" light still lit on an
obviously non-functional protector? You tell me since you
recommend those silly plug-in surge protectors. Little hint:
the light can only report when the protector is defective but
cannot report if the protector is good. You should have known
that:
http://www.zerosurge.com/HTML/movs.html

Second little hint - the protector cannot tell when MOVs have
degraded. They can only report when MOV was so grossly
undersized as to vaporize - as so many grossly undersized
plug-in protectors do.

This 'light' feature is so old in America that it was even
on surge protectors tested in PC Magazine in the 1980s. So
now you insult the US for importing Chinese 'junk'. Where in
that insult is a technical fact? How does that light work?

"So again, the plug-in protector still does not provide
effective protection." Your technical response? Another
insult:

Complete crap. As usual.

Mike. When are you going to challenge the example of wire
impedance. Remember that wire impedance that leaves a surge
protector at 13,000 volts when it is suppose to be earthing a
trivial 100 amp surge? Why, Mike, do you repeatedly avoid
facts by posting more insults? Do your routinely ignore
things you don't like?

So now Mike. Please enlighten us. How does that "warning
lamp to indicate when the protective devices have degraded"
work? Show us how that light can measure let-through voltage
of an MOV. You ignore the impedance in 18 meters of wire to
lie about plug-in protector effectiveness. So maybe just
once, provide us with good technical knowledge. How does that
light know the let-through voltage of MOVs? Spread your
wisdom.

Feel free to top post or bottom post. Impart your
comprehension on how all this stuff works. Show us how a
light can determine that the internal MOV has 'degraded'.
Also please explain what happened to that 130 ohms of
impedance to earth ground from the wall receptacle. Another
little hint: you cannot.

You seem to have so many personal insults that I think I
will keep the so many you have given me. After all, you are
going to show us how smart you are. You are going to show us
how that light reports that MOVs have degraded.

 

[VWWall]

Furthermore we have direct from the US Army's Training
manual TM5-690 the size a wire must be to earth a direct
strike:

http://www.usace.army.mil/inet/usace-docs/armytm/tm5-690/c-3.pdf
is 14 AWG copper, 12 AWG aluminum, or 1 inch wide solid
strip. Again it is nothing short of speculation that massive
conductors are required to earth lightning. But speculation
has been widespread and challenged in this thread. Cited by
this author here and elsewhere are numbers from those who
actually do the work. I wish Mike Tomlinson understood the
concept better. Then he would not have to resort to personal
insults to make his claims.

Table 3.3 from the above document shows 14 AWG copper "strand" to
be used. I does not state the number of "strands" used in the
"cable". A simple division of the pounds/1000 feet, the resistance or
the cir mils given in that table, would indicate that the "ground cable"
is composed of about 15 "strands" of 14 AWG copper wire.

No personal insult intended, but if you cite "handbook" information, you
should make a better effort to understand it!

VWWall, P.E.

 

[Lem]

I've been running multiple home PCs in the UK for around 15
years and have never had a problem with mains spikes, or ever
heard from anyone who has had a problem.

OTOH I've heard several reports of hardware losses in the US
caused by brownouts and spikes. The power distribution systems
aren't as well protected as in the UK, possibly because of the
greater average distance from substation to home, and poor
earthing policies.

I've discussed internal wiring systems with US techies, some
of them are installing domestic wiring using uninsulated
cables.

Uninsulated? What does that look like?

 

[Lem]

That's not how lightning protectors work. They create a corona
discharge around the building, dissipating charge buildup
immediately around the site. That means that a strike is more
likely to happen elsewhere.

The copper strap has a cross section of less than an inch,
nowhere near enough to safely shunt a real strike to earth. If
the building does get hit the strike will still do nearly as
much damage as if it was not there.

Then what is the point of putting in the strap?

 

[Tim Auton]

Are surge protectors on the main power supply actually needed in
the UK?

w_tom is currently debating this on sci.electronics.basics and another
4 or so crossposted groups. You may all wish to go to and read that
thread too, particularly the exchanges between w_tom and Charles
Perry.

http://groups.google.com/groups?q=group:sci.electronics.basics+"Whole+house+surge+suppressors"


Tim