\"surge protectors\"...

[Martin Brown]

On 09/01/2023 23:31, Don Y wrote:

On 1/9/2023 10:54 AM, Joe Gwinn wrote:
I would have added, get an outlet strip/surge protector that is
metal. Belkin makes some that use the duplex  sockets. Plastic
burns.

Actually, there is a far better option in the US, a \"whole house surge
protector\" (google for this without the quotes).

Yeah, she\'s not going to go that route.  Cost of unit plus cost of
installation... cheaper to plan on replacing the kit that MIGHT
get damaged -- and hope none of it does.

I\'ve been on a crusade to prod neighbors into installing pressure
regulators on the municipal water supply -- our water pressure exceeds
100psi (most appliances are designed for a limit of ~80).  And,
water pressure is constant, not some transient that comes along
during freak storms!

Water pressure can be a bit of a nuisance in hilly places. Ours is a bit
on the high side and it can go very high in the middle of the night when
almost no one is drawing water domestically.

But, the cost of the PRV, expansion tank and labor to install
has folks ignoring the problem.

Tends to break things like seals and cause leaks if you ignore it.

FWIW I use a Belkin surge arrestor on my kit with mains coming in on
poles I expect to take a lightning hit nearby every couple of years. The
UPS has its own internal surge protection as well.

Even so I have seen calorific sparks between my modem and ground that
occurred before the sound of the lightning strike very nearby! It had a
very sharp click sizzle sound as opposed to the loud deep thump.

--
Regards,
Martin Brown

 

[Martin Brown]

On 09/01/2023 23:31, Don Y wrote:

On 1/9/2023 10:54 AM, Joe Gwinn wrote:
I would have added, get an outlet strip/surge protector that is
metal. Belkin makes some that use the duplex  sockets. Plastic
burns.

Actually, there is a far better option in the US, a \"whole house surge
protector\" (google for this without the quotes).

Yeah, she\'s not going to go that route.  Cost of unit plus cost of
installation... cheaper to plan on replacing the kit that MIGHT
get damaged -- and hope none of it does.

I\'ve been on a crusade to prod neighbors into installing pressure
regulators on the municipal water supply -- our water pressure exceeds
100psi (most appliances are designed for a limit of ~80).  And,
water pressure is constant, not some transient that comes along
during freak storms!

Water pressure can be a bit of a nuisance in hilly places. Ours is a bit
on the high side and it can go very high in the middle of the night when
almost no one is drawing water domestically.

But, the cost of the PRV, expansion tank and labor to install
has folks ignoring the problem.

Tends to break things like seals and cause leaks if you ignore it.

FWIW I use a Belkin surge arrestor on my kit with mains coming in on
poles I expect to take a lightning hit nearby every couple of years. The
UPS has its own internal surge protection as well.

Even so I have seen calorific sparks between my modem and ground that
occurred before the sound of the lightning strike very nearby! It had a
very sharp click sizzle sound as opposed to the loud deep thump.

--
Regards,
Martin Brown

 

[Jeroen Belleman]

Martin Brown wrote:

On 09/01/2023 23:21, Don Y wrote:
On 1/9/2023 7:52 AM, Ralph Mowery wrote:

It fried the protectors but none of the equipment was damaged.
It took out the TV and some other things in the house next door.
So I would say get a good one or If you get an inexpensive protector it
may or may not do any good.

I question whether the designs are really worth much, if anything -- at
least in places where the utilities are buried. A direct strike on a
home
is equally likely to send surges through network cables, phone lines,
etc. Should you replace all of that with fibre?

I had a Boca modem (back in the days when they were in extruded
aluminium cases) that got fried by lightning strike with underground
cables and no surge protection on any of the cables.

Somehow lightning will find a way to do damage if it wants to.
Irrespective of how fancy the protection you put around the kit.

Respect for the designers of these mountain-top radio relays
that get hit by lightning all the time, yet continue to work
normally.

Jeroen Belleman

 

[Jeroen Belleman]

Martin Brown wrote:

On 09/01/2023 23:21, Don Y wrote:
On 1/9/2023 7:52 AM, Ralph Mowery wrote:

It fried the protectors but none of the equipment was damaged.
It took out the TV and some other things in the house next door.
So I would say get a good one or If you get an inexpensive protector it
may or may not do any good.

I question whether the designs are really worth much, if anything -- at
least in places where the utilities are buried. A direct strike on a
home
is equally likely to send surges through network cables, phone lines,
etc. Should you replace all of that with fibre?

I had a Boca modem (back in the days when they were in extruded
aluminium cases) that got fried by lightning strike with underground
cables and no surge protection on any of the cables.

Somehow lightning will find a way to do damage if it wants to.
Irrespective of how fancy the protection you put around the kit.

Respect for the designers of these mountain-top radio relays
that get hit by lightning all the time, yet continue to work
normally.

Jeroen Belleman

 

[Jeroen Belleman]

Martin Brown wrote:

On 09/01/2023 23:21, Don Y wrote:
On 1/9/2023 7:52 AM, Ralph Mowery wrote:

It fried the protectors but none of the equipment was damaged.
It took out the TV and some other things in the house next door.
So I would say get a good one or If you get an inexpensive protector it
may or may not do any good.

I question whether the designs are really worth much, if anything -- at
least in places where the utilities are buried. A direct strike on a
home
is equally likely to send surges through network cables, phone lines,
etc. Should you replace all of that with fibre?

I had a Boca modem (back in the days when they were in extruded
aluminium cases) that got fried by lightning strike with underground
cables and no surge protection on any of the cables.

Somehow lightning will find a way to do damage if it wants to.
Irrespective of how fancy the protection you put around the kit.

Respect for the designers of these mountain-top radio relays
that get hit by lightning all the time, yet continue to work
normally.

Jeroen Belleman

 

[server]

On Mon, 9 Jan 2023 10:36:13 +0000, Martin Brown
<\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 09/01/2023 05:44, Don Y wrote:
Neighbor asked me about \"outlet strips with built in protectors\".

My advice was that they are no better than just an outlet strip
(assuming her reference to \"protectors\" was wrt SURGE protection
and she\'s looking at \"cheap\" products).  I\'ve not seen anything
\"substantial enough\" in an outlet strip to really make a difference.
(maybe as a hash filter to keep crud from wall warts off the line?)

Our utilities are below grade.  Anything on the high tension side
will be filtered by the local transformers.  One to four subscribers
share a transformer.

Should I have told her otherwise?

The problem with those cheap surge protectors is that they degrade
over time if frequently stressed by overvoltages e.g. due to frequent
thunderstorms.Some may even have lights to tell if they are still
usable.

A better solution is to have a spark gap in the main distribution
panel and simple protectors at the outlet strips. The spark gap takes
out most of the energy, so the peak energy reaching the power strip
protector is greatly reduced prolonging the strip protector lifetime.A
spark gap alone will only absorb the highest peaks and a separate
protector will reduce the voltage further. It is important that there
are some resistance (and inductance) between the spark gap and
arrestor to further limit the power into the protector.The house
wiring usually have sufficient resistance and inductance.

I think they can sometimes make a difference for modest voltage spikes
coming in on lines due to lightning strikes. But you can be either lucky
or unlucky even then. My ADSL modem had a big fat calorific spark about
an inch long jump off it when we took a hit nearby. It fried most
peoples modems and bedside clocks but somehow ours escaped and when
power was restored the modem was none the worse for its ordeal.

Protecting a device that is connected only to a single network (such
as mains only or telephone only) is simple, Things get nasty when
multiple networks are connected to the same device such as a modem
(mains and telephone network). All the lines should go through a
combined device with protectors for both mains and telephone
(equipotential bonding).

Contrast that with mainframe computer buildings I have been in where the
terminal concentrators were heavily protected by chunky professionally
installed surge arresters on hefty earthed copper bus bars and yet the
strike got through and zapped every line driver board and also vaporised
the internal telephone circuits down to the switchboard. It was a strike
to the apex of the roof of an industrial shed type building with metal
roof and brick walls. Hell of a big bang then darkness.

Sounds like the lightning got into a local grounding electrode to
which the protector grounds were also connected. Due to the grounding
electrode grounding resistance, the grounding electrode experienced a
ground bounce due to the lightning rising the ground potential to
several kilovolts. Other networks, such as the telephone network was
grounded at some distance and not suffering the ground bounce, thud
large currents might have flown causing all kinds of damage.

Looking naively at the ground system schematic diagram one might have
assumed that all grounds are at all times at some common \"absolute\"
ground, while in reality the ground potential in different parts of
the grounding network was different due to ground bounce. .

 

[server]

On Mon, 9 Jan 2023 10:36:13 +0000, Martin Brown
<\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 09/01/2023 05:44, Don Y wrote:
Neighbor asked me about \"outlet strips with built in protectors\".

My advice was that they are no better than just an outlet strip
(assuming her reference to \"protectors\" was wrt SURGE protection
and she\'s looking at \"cheap\" products).  I\'ve not seen anything
\"substantial enough\" in an outlet strip to really make a difference.
(maybe as a hash filter to keep crud from wall warts off the line?)

Our utilities are below grade.  Anything on the high tension side
will be filtered by the local transformers.  One to four subscribers
share a transformer.

Should I have told her otherwise?

The problem with those cheap surge protectors is that they degrade
over time if frequently stressed by overvoltages e.g. due to frequent
thunderstorms.Some may even have lights to tell if they are still
usable.

A better solution is to have a spark gap in the main distribution
panel and simple protectors at the outlet strips. The spark gap takes
out most of the energy, so the peak energy reaching the power strip
protector is greatly reduced prolonging the strip protector lifetime.A
spark gap alone will only absorb the highest peaks and a separate
protector will reduce the voltage further. It is important that there
are some resistance (and inductance) between the spark gap and
arrestor to further limit the power into the protector.The house
wiring usually have sufficient resistance and inductance.

I think they can sometimes make a difference for modest voltage spikes
coming in on lines due to lightning strikes. But you can be either lucky
or unlucky even then. My ADSL modem had a big fat calorific spark about
an inch long jump off it when we took a hit nearby. It fried most
peoples modems and bedside clocks but somehow ours escaped and when
power was restored the modem was none the worse for its ordeal.

Protecting a device that is connected only to a single network (such
as mains only or telephone only) is simple, Things get nasty when
multiple networks are connected to the same device such as a modem
(mains and telephone network). All the lines should go through a
combined device with protectors for both mains and telephone
(equipotential bonding).

Contrast that with mainframe computer buildings I have been in where the
terminal concentrators were heavily protected by chunky professionally
installed surge arresters on hefty earthed copper bus bars and yet the
strike got through and zapped every line driver board and also vaporised
the internal telephone circuits down to the switchboard. It was a strike
to the apex of the roof of an industrial shed type building with metal
roof and brick walls. Hell of a big bang then darkness.

Sounds like the lightning got into a local grounding electrode to
which the protector grounds were also connected. Due to the grounding
electrode grounding resistance, the grounding electrode experienced a
ground bounce due to the lightning rising the ground potential to
several kilovolts. Other networks, such as the telephone network was
grounded at some distance and not suffering the ground bounce, thud
large currents might have flown causing all kinds of damage.

Looking naively at the ground system schematic diagram one might have
assumed that all grounds are at all times at some common \"absolute\"
ground, while in reality the ground potential in different parts of
the grounding network was different due to ground bounce. .

 

[server]

On Mon, 9 Jan 2023 10:36:13 +0000, Martin Brown
<\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 09/01/2023 05:44, Don Y wrote:
Neighbor asked me about \"outlet strips with built in protectors\".

My advice was that they are no better than just an outlet strip
(assuming her reference to \"protectors\" was wrt SURGE protection
and she\'s looking at \"cheap\" products).  I\'ve not seen anything
\"substantial enough\" in an outlet strip to really make a difference.
(maybe as a hash filter to keep crud from wall warts off the line?)

Our utilities are below grade.  Anything on the high tension side
will be filtered by the local transformers.  One to four subscribers
share a transformer.

Should I have told her otherwise?

The problem with those cheap surge protectors is that they degrade
over time if frequently stressed by overvoltages e.g. due to frequent
thunderstorms.Some may even have lights to tell if they are still
usable.

A better solution is to have a spark gap in the main distribution
panel and simple protectors at the outlet strips. The spark gap takes
out most of the energy, so the peak energy reaching the power strip
protector is greatly reduced prolonging the strip protector lifetime.A
spark gap alone will only absorb the highest peaks and a separate
protector will reduce the voltage further. It is important that there
are some resistance (and inductance) between the spark gap and
arrestor to further limit the power into the protector.The house
wiring usually have sufficient resistance and inductance.

I think they can sometimes make a difference for modest voltage spikes
coming in on lines due to lightning strikes. But you can be either lucky
or unlucky even then. My ADSL modem had a big fat calorific spark about
an inch long jump off it when we took a hit nearby. It fried most
peoples modems and bedside clocks but somehow ours escaped and when
power was restored the modem was none the worse for its ordeal.

Protecting a device that is connected only to a single network (such
as mains only or telephone only) is simple, Things get nasty when
multiple networks are connected to the same device such as a modem
(mains and telephone network). All the lines should go through a
combined device with protectors for both mains and telephone
(equipotential bonding).

Contrast that with mainframe computer buildings I have been in where the
terminal concentrators were heavily protected by chunky professionally
installed surge arresters on hefty earthed copper bus bars and yet the
strike got through and zapped every line driver board and also vaporised
the internal telephone circuits down to the switchboard. It was a strike
to the apex of the roof of an industrial shed type building with metal
roof and brick walls. Hell of a big bang then darkness.

Sounds like the lightning got into a local grounding electrode to
which the protector grounds were also connected. Due to the grounding
electrode grounding resistance, the grounding electrode experienced a
ground bounce due to the lightning rising the ground potential to
several kilovolts. Other networks, such as the telephone network was
grounded at some distance and not suffering the ground bounce, thud
large currents might have flown causing all kinds of damage.

Looking naively at the ground system schematic diagram one might have
assumed that all grounds are at all times at some common \"absolute\"
ground, while in reality the ground potential in different parts of
the grounding network was different due to ground bounce. .

 

[Jan Panteltje]

On a sunny day (Wed, 11 Jan 2023 09:38:03 +0000) it happened piglet
<erichpwagner@hotmail.com> wrote in <tpm01r$rqu0$1@dont-email.me>:

On 10/01/2023 13:16, Ricky wrote:
I wonder how they test them in production? Most likely, not at all. That would cost money.


MOVs are typically tested for clamping voltage at 1mA test current.
Since the outlet maker has to test the final product for continuity and
resistance anyhow the extra MOV test is trivial.

piglet

The surge protector I use has VDRs in SERIES with spark gaps:
http://panteltje.com/pub/mains_protector_IXIMG_0503.JPG
http://panteltje.com/pub/mains_protector_IXIMG_0501.JPG
http://panteltje.com/pub/mains_protector_IXIMG_0504.JPG

I think the idea is that when ignited the spark gap \'resistance\' is next to zero
and the VDR then limits the voltage (preventing a dead short on the line).
Normaly those 2 VDRs do nothing.
Those VDRs are between the mains wires and ground
(you never know which one is live and witch one is neutral).

There is a third VDR between live an neutral.

So far this thing has worked OK.

 

[Jan Panteltje]

On a sunny day (Wed, 11 Jan 2023 09:38:03 +0000) it happened piglet
<erichpwagner@hotmail.com> wrote in <tpm01r$rqu0$1@dont-email.me>:

On 10/01/2023 13:16, Ricky wrote:
I wonder how they test them in production? Most likely, not at all. That would cost money.


MOVs are typically tested for clamping voltage at 1mA test current.
Since the outlet maker has to test the final product for continuity and
resistance anyhow the extra MOV test is trivial.

piglet

The surge protector I use has VDRs in SERIES with spark gaps:
http://panteltje.com/pub/mains_protector_IXIMG_0503.JPG
http://panteltje.com/pub/mains_protector_IXIMG_0501.JPG
http://panteltje.com/pub/mains_protector_IXIMG_0504.JPG

I think the idea is that when ignited the spark gap \'resistance\' is next to zero
and the VDR then limits the voltage (preventing a dead short on the line).
Normaly those 2 VDRs do nothing.
Those VDRs are between the mains wires and ground
(you never know which one is live and witch one is neutral).

There is a third VDR between live an neutral.

So far this thing has worked OK.

 

[Jan Panteltje]

On a sunny day (Wed, 11 Jan 2023 09:38:03 +0000) it happened piglet
<erichpwagner@hotmail.com> wrote in <tpm01r$rqu0$1@dont-email.me>:

On 10/01/2023 13:16, Ricky wrote:
I wonder how they test them in production? Most likely, not at all. That would cost money.


MOVs are typically tested for clamping voltage at 1mA test current.
Since the outlet maker has to test the final product for continuity and
resistance anyhow the extra MOV test is trivial.

piglet

The surge protector I use has VDRs in SERIES with spark gaps:
http://panteltje.com/pub/mains_protector_IXIMG_0503.JPG
http://panteltje.com/pub/mains_protector_IXIMG_0501.JPG
http://panteltje.com/pub/mains_protector_IXIMG_0504.JPG

I think the idea is that when ignited the spark gap \'resistance\' is next to zero
and the VDR then limits the voltage (preventing a dead short on the line).
Normaly those 2 VDRs do nothing.
Those VDRs are between the mains wires and ground
(you never know which one is live and witch one is neutral).

There is a third VDR between live an neutral.

So far this thing has worked OK.

 

[Martin Brown]

On 10/01/2023 10:09, Jeroen Belleman wrote:

Martin Brown wrote:
On 09/01/2023 23:21, Don Y wrote:
On 1/9/2023 7:52 AM, Ralph Mowery wrote:

It fried the protectors but none of the equipment was damaged.
It took out the TV and some other things in the house next door.
So I would say get a good one or If you get an inexpensive protector it
may or may not do any good.

I question whether the designs are really worth much, if anything -- at
least in places where the utilities are buried.  A direct strike on a
home
is equally likely to send surges through network cables, phone lines,
etc.  Should you replace all of that with fibre?

I had a Boca modem (back in the days when they were in extruded
aluminium cases) that got fried by lightning strike with underground
cables and no surge protection on any of the cables.

Somehow lightning will find a way to do damage if it wants to.
Irrespective of how fancy the protection you put around the kit.


Respect for the designers of these mountain-top radio relays
that get hit by lightning all the time, yet continue to work
normally.

Indeed.

And the guys who work on top of Old Baldy Peak in New Mexico at the
lightning research centre where they provoke strikes against their kit.

http://langmuir.nmt.edu

I still recall an impressive cloud to ground strike against a 500m mast
during a typhoon when I lived in Japan. It was completely awesome like
the death star with three different lightning strikes converging onto
the apex from roughly equally spaced clouds around and above it.

--
Regards,
Martin Brown

 

[Martin Brown]

On 10/01/2023 10:09, Jeroen Belleman wrote:

Martin Brown wrote:
On 09/01/2023 23:21, Don Y wrote:
On 1/9/2023 7:52 AM, Ralph Mowery wrote:

It fried the protectors but none of the equipment was damaged.
It took out the TV and some other things in the house next door.
So I would say get a good one or If you get an inexpensive protector it
may or may not do any good.

I question whether the designs are really worth much, if anything -- at
least in places where the utilities are buried.  A direct strike on a
home
is equally likely to send surges through network cables, phone lines,
etc.  Should you replace all of that with fibre?

I had a Boca modem (back in the days when they were in extruded
aluminium cases) that got fried by lightning strike with underground
cables and no surge protection on any of the cables.

Somehow lightning will find a way to do damage if it wants to.
Irrespective of how fancy the protection you put around the kit.


Respect for the designers of these mountain-top radio relays
that get hit by lightning all the time, yet continue to work
normally.

Indeed.

And the guys who work on top of Old Baldy Peak in New Mexico at the
lightning research centre where they provoke strikes against their kit.

http://langmuir.nmt.edu

I still recall an impressive cloud to ground strike against a 500m mast
during a typhoon when I lived in Japan. It was completely awesome like
the death star with three different lightning strikes converging onto
the apex from roughly equally spaced clouds around and above it.

--
Regards,
Martin Brown

 

[Martin Brown]

On 10/01/2023 10:09, Jeroen Belleman wrote:

Martin Brown wrote:
On 09/01/2023 23:21, Don Y wrote:
On 1/9/2023 7:52 AM, Ralph Mowery wrote:

It fried the protectors but none of the equipment was damaged.
It took out the TV and some other things in the house next door.
So I would say get a good one or If you get an inexpensive protector it
may or may not do any good.

I question whether the designs are really worth much, if anything -- at
least in places where the utilities are buried.  A direct strike on a
home
is equally likely to send surges through network cables, phone lines,
etc.  Should you replace all of that with fibre?

I had a Boca modem (back in the days when they were in extruded
aluminium cases) that got fried by lightning strike with underground
cables and no surge protection on any of the cables.

Somehow lightning will find a way to do damage if it wants to.
Irrespective of how fancy the protection you put around the kit.


Respect for the designers of these mountain-top radio relays
that get hit by lightning all the time, yet continue to work
normally.

Indeed.

And the guys who work on top of Old Baldy Peak in New Mexico at the
lightning research centre where they provoke strikes against their kit.

http://langmuir.nmt.edu

I still recall an impressive cloud to ground strike against a 500m mast
during a typhoon when I lived in Japan. It was completely awesome like
the death star with three different lightning strikes converging onto
the apex from roughly equally spaced clouds around and above it.

--
Regards,
Martin Brown

 

[Martin Brown]

On 09/01/2023 05:44, Don Y wrote:

Neighbor asked me about \"outlet strips with built in protectors\".

My advice was that they are no better than just an outlet strip
(assuming her reference to \"protectors\" was wrt SURGE protection
and she\'s looking at \"cheap\" products).  I\'ve not seen anything
\"substantial enough\" in an outlet strip to really make a difference.
(maybe as a hash filter to keep crud from wall warts off the line?)

Our utilities are below grade.  Anything on the high tension side
will be filtered by the local transformers.  One to four subscribers
share a transformer.

Should I have told her otherwise?

I think they can sometimes make a difference for modest voltage spikes
coming in on lines due to lightning strikes. But you can be either lucky
or unlucky even then. My ADSL modem had a big fat calorific spark about
an inch long jump off it when we took a hit nearby. It fried most
peoples modems and bedside clocks but somehow ours escaped and when
power was restored the modem was none the worse for its ordeal.

Contrast that with mainframe computer buildings I have been in where the
terminal concentrators were heavily protected by chunky professionally
installed surge arresters on hefty earthed copper bus bars and yet the
strike got through and zapped every line driver board and also vaporised
the internal telephone circuits down to the switchboard. It was a strike
to the apex of the roof of an industrial shed type building with metal
roof and brick walls. Hell of a big bang then darkness.


--
Regards,
Martin Brown

 

[Martin Brown]

On 09/01/2023 05:44, Don Y wrote:

Neighbor asked me about \"outlet strips with built in protectors\".

My advice was that they are no better than just an outlet strip
(assuming her reference to \"protectors\" was wrt SURGE protection
and she\'s looking at \"cheap\" products).  I\'ve not seen anything
\"substantial enough\" in an outlet strip to really make a difference.
(maybe as a hash filter to keep crud from wall warts off the line?)

Our utilities are below grade.  Anything on the high tension side
will be filtered by the local transformers.  One to four subscribers
share a transformer.

Should I have told her otherwise?

I think they can sometimes make a difference for modest voltage spikes
coming in on lines due to lightning strikes. But you can be either lucky
or unlucky even then. My ADSL modem had a big fat calorific spark about
an inch long jump off it when we took a hit nearby. It fried most
peoples modems and bedside clocks but somehow ours escaped and when
power was restored the modem was none the worse for its ordeal.

Contrast that with mainframe computer buildings I have been in where the
terminal concentrators were heavily protected by chunky professionally
installed surge arresters on hefty earthed copper bus bars and yet the
strike got through and zapped every line driver board and also vaporised
the internal telephone circuits down to the switchboard. It was a strike
to the apex of the roof of an industrial shed type building with metal
roof and brick walls. Hell of a big bang then darkness.


--
Regards,
Martin Brown

 

[Martin Brown]

On 09/01/2023 05:44, Don Y wrote:

Neighbor asked me about \"outlet strips with built in protectors\".

My advice was that they are no better than just an outlet strip
(assuming her reference to \"protectors\" was wrt SURGE protection
and she\'s looking at \"cheap\" products).  I\'ve not seen anything
\"substantial enough\" in an outlet strip to really make a difference.
(maybe as a hash filter to keep crud from wall warts off the line?)

Our utilities are below grade.  Anything on the high tension side
will be filtered by the local transformers.  One to four subscribers
share a transformer.

Should I have told her otherwise?

I think they can sometimes make a difference for modest voltage spikes
coming in on lines due to lightning strikes. But you can be either lucky
or unlucky even then. My ADSL modem had a big fat calorific spark about
an inch long jump off it when we took a hit nearby. It fried most
peoples modems and bedside clocks but somehow ours escaped and when
power was restored the modem was none the worse for its ordeal.

Contrast that with mainframe computer buildings I have been in where the
terminal concentrators were heavily protected by chunky professionally
installed surge arresters on hefty earthed copper bus bars and yet the
strike got through and zapped every line driver board and also vaporised
the internal telephone circuits down to the switchboard. It was a strike
to the apex of the roof of an industrial shed type building with metal
roof and brick walls. Hell of a big bang then darkness.


--
Regards,
Martin Brown

 

[Martin Rid]

Don Y <blockedofcourse@foo.invalid> Wrote in message:r
> Neighbor asked me about \"outlet strips with built in protectors\".My advice was that they are no better than just an outlet strip(assuming her reference to \"protectors\" was wrt SURGE protectionand she\'s looking at \"cheap\" products). I\'ve not seen anything\"substantial enough\" in an outlet strip to really make a difference.(maybe as a hash filter to keep crud from wall warts off the line?)Our utilities are below grade. Anything on the high tension sidewill be filtered by the local transformers. One to four subscribersshare a transformer.Should I have told her otherwise?

I would have added, get an outlet strip/surge protector that is
metal. Belkin makes some that use the duplex sockets. Plastic
burns.

Cheers
--


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[Martin Rid]

Don Y <blockedofcourse@foo.invalid> Wrote in message:r
> Neighbor asked me about \"outlet strips with built in protectors\".My advice was that they are no better than just an outlet strip(assuming her reference to \"protectors\" was wrt SURGE protectionand she\'s looking at \"cheap\" products). I\'ve not seen anything\"substantial enough\" in an outlet strip to really make a difference.(maybe as a hash filter to keep crud from wall warts off the line?)Our utilities are below grade. Anything on the high tension sidewill be filtered by the local transformers. One to four subscribersshare a transformer.Should I have told her otherwise?

I would have added, get an outlet strip/surge protector that is
metal. Belkin makes some that use the duplex sockets. Plastic
burns.

Cheers
--


----Android NewsGroup Reader----
https://piaohong.s3-us-west-2.amazonaws.com/usenet/index.html

 

[Martin Rid]

Don Y <blockedofcourse@foo.invalid> Wrote in message:r
> Neighbor asked me about \"outlet strips with built in protectors\".My advice was that they are no better than just an outlet strip(assuming her reference to \"protectors\" was wrt SURGE protectionand she\'s looking at \"cheap\" products). I\'ve not seen anything\"substantial enough\" in an outlet strip to really make a difference.(maybe as a hash filter to keep crud from wall warts off the line?)Our utilities are below grade. Anything on the high tension sidewill be filtered by the local transformers. One to four subscribersshare a transformer.Should I have told her otherwise?

I would have added, get an outlet strip/surge protector that is
metal. Belkin makes some that use the duplex sockets. Plastic
burns.

Cheers
--


----Android NewsGroup Reader----
https://piaohong.s3-us-west-2.amazonaws.com/usenet/index.html