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?

On Monday, January 9, 2023 at 12:44:11 AM UTC-5, 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've tried to explain to people in Puerto Rico that the cheap surge protectors are pretty much crap. They have a very low level of protection and there's no way to tell when that is blown. I've been staying at Airbnb places and one landlord insisted that a microwave oven that stopped working was because of a surge. She wouldn't even talk to the manufacturer about a warranty claim. So she bought a surge protector, and expects the tenants to remember to turn it off when not in use. Of course, that would be a good level of protection... if surges were actually the problem... and people remember to turn it off.

I look at all the appliances that don't break, and wonder why a surge would target one and not the other dozen?

I also have a charm against alligators. The entire time I've worn this charm, I've been safe from alligators. There are people in Florida who don't have them and have been attacked by alligators. Pretty good proof they work, no?

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

On a sunny day (Sun, 8 Jan 2023 22:44:01 -0700) it happened Don Y
<blockedofcourse@foo.invalid> wrote in <tpg9j4$3qo0$1@dont-email.me>:

>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 bought such a mains surge protector on the local market here years ago:
http://panteltje.com/pub/mains_protector_IXIMG_0503.JPG

Curiosity made me look inside:
http://panteltje.com/pub/mains_protector_IXIMG_0501.JPG
2 spark gaps and 3 VDRs
Works great so far.

Did not cost much, 5 Euro / dollars?

On a sunny day (Sun, 8 Jan 2023 21:52:58 -0800 (PST)) it happened Ricky
<gnuarm.deletethisbit@gmail.com> wrote in
<14cf2925-99be-412b-ae2f-87f09872443bn@googlegroups.com>:

>On Monday, January 9, 2023 at 12:44:11 AM UTC-5, 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've tried to explain to people in Puerto Rico that the cheap surge protectors
>are pretty much crap. They have a very low level of protection and there's
>no way to tell when that is blown. I've been staying at Airbnb places
>and one landlord insisted that a microwave oven that stopped working was because
>of a surge. She wouldn't even talk to the manufacturer about a warranty
>claim. So she bought a surge protector, and expects the tenants to remember
>to turn it off when not in use. Of course, that would be a good level
>of protection... if surges were actually the problem... and people remember
>to turn it off.
>
>I look at all the appliances that don't break, and wonder why a surge would
>target one and not the other dozen?

Because, for example Whirlpool power supplies in their washers are a series switcher
chip straight from the mains that will blow up on a surge.
Depends on the mains group / phase it is on too, if the neighbor is
using his electric drill or whatever

>I also have a charm against alligators. The entire time I've worn this charm,
>I've been safe from alligators. There are people in Florida who don't have
>them and have been attacked by alligators. Pretty good proof they work,
>no?

I don't have one, but the alligators that I keep just under the trapdoor
at the front door are so fat now from burglars they cannot be bothered.

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

On 1/9/2023 3:36 AM, Martin Brown wrote:
>> 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.

I think our below grade services make the sorts of "cruft" you'd
encounter with flying wires much less severe. We've been here ~30 years
and I've never had a problem (and I don't unplug stuff during storms).

And, the only outages we've had have been due to equipment failures.
(transformers are daisy-chained together so the primary conductor
exists in "segments". when a segment fails, everything downstream
from it gets dumped. and, everything upstream sees that dump!)

She's looking for something along the lines of: "If you buy one
of these (cheap!) outlet strips, your TV, hifi, DVR, etc. will
all be 'protected'". As if that means she'll never lose one
to a line disturbance. :-/

[*I* sure as hell am not going to give her that impression!
There's ALWAYS a bigger transient that can eat your lunch!]

> 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.

One of the homes I'd occupied got struck, while I was off at work.
I kept trying to reach my other half (I was working late) and the
phone was perpetually busy: "Who the hell can she be talking to
for all this time??"

Turns out, the strike had fried the phones so they were off-hook.
She was near tears because she couldn't call out to get in touch
with me.

[Losing power is <shrug>. Losing natural gas supply raises
eyebrows. Losing phone service (decades ago) is unheard of!]

Also managed to "magnetize" the (CRT) TV! Took a gazillion
power-on degaussing cycles before the color came back to normal.

In article <tpg9j4$3qo0$1@dont-email.me>, blockedofcourse@foo.invalid
says...
>
> 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 under say $ 20 strips are not very good.

I had a couple of the $ 50 or so protectors on the TV and some other
equipment. The transformer that fed my house exploded during a storm.
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.

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. .

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

On Mon, 9 Jan 2023 12:18:57 -0500 (EST), Martin Rid
<martin_riddle@verison.net> wrote:

>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.

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

This is wired into the power panel of the house, and is physically
huge compared to those little surge protectors in power strips, and
provides warning that the protector is no longer effective (worn out).

I have one in my house. They were pioneered in Florida and Texas,
which are flat and very prone to thunderstorms.

In theory this should be installed by an electrician, but I installed
mine many years ago. Hmm. May be time to replace it.

I don't know what the EU/UK versions of this are called.

Joe Gwinn

On 1/9/2023 7:52 AM, Ralph Mowery wrote:
> The under say $ 20 strips are not very good.
>
> I had a couple of the $ 50 or so protectors on the TV and some other
> equipment. The transformer that fed my house exploded during a storm.

Do you have overhead power? Was the damage to the transformer due to
a lightning strike?

> 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?

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!

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

> This is wired into the power panel of the house, and is physically
> huge compared to those little surge protectors in power strips, and
> provides warning that the protector is no longer effective (worn out).
>
> I have one in my house. They were pioneered in Florida and Texas,
> which are flat and very prone to thunderstorms.
>
> In theory this should be installed by an electrician, but I installed
> mine many years ago. Hmm. May be time to replace it.
>
> I don't know what the EU/UK versions of this are called.
>
> Joe Gwinn

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.

--
Regards,
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 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

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

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?
>

They are useless against high energy events but can have a place in
protecting against the much more frequent low energy transients from
contacts arcing and switching inductive loads. Those transients often
arise from appliances within the building or even same room. Typically
they gradually eat away at the metalization of film cap droppers.

piglet

On 1/10/2023 3:06 AM, Martin Brown wrote:
> 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.

We live by a wash, down low wrt the rest of town. Our domestic
water is sourced from wells scattered around town. Being near a wash,
there's a well located ~100 yds from here.

The wells do some *limited* water treatment at the site (I think
mainly chlorination). Then, PUSH the water into the distribution
system directly. I.e., *my* water most likely comes from the
well nearby when its pumps are running -- because THAT water is on
its way past my house and *up* into the distribution system.

Of course, as demand has increased, the water mains largely have not.
So, to get more water, use more pressure.

>> 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.

Yes. We lost the flex line connecting the toilet (tank)
to the water supply one night. Thankfully, I caught it
almost immediately and shut off the water supply at the toilet.

About that time, the water department folks were doing some
work nearby. I asked to borrow their pressure gauge (it is
designed to screw onto a hose bibb for easy access to the
water lines at a residence).

Then, went out and bought a PRV and expansion tank.

[The PRVs have backflow valves that ensure the pressure
on the regulated side never exceeds the pressure on the
input side -- easily happens when folks don't have an
expansion tank! But, this effectively means the PRV doesn't
do anything for the max pressure you see domestically]

> 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.

All of my machines have their own UPSs. (Surplus UPSs are
essentially free -- cost of batteries being the only limiting
factor. But, even with a dead battery, they offer some
functionality as outlet strips, master on/off switches,
power consumption monitors, etc.)

> 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.

Yes, our (childhood) home was struck one night while I was watching TV.
At the time, I was playing the "every 5 seconds is a mile" game when
there was a *crack* and simultaneous flash. "Wow! That one was close!"

Next morning, I noticed a pile of bark on the ground by the walnut tree
adjacent to the house.

And, a large "stripe" going up to the top of the tree where the
bark had been "boiled off".

I suddenly knew just how close the strike had been!

On Monday, January 9, 2023 at 9:52:16 AM UTC-5, Ralph Mowery wrote:
> In article <tpg9j4$3qo0$1...@dont-email.me>, blocked...@foo.invalid
> says...
> >
> > 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 under say $ 20 strips are not very good.
>
> I had a couple of the $ 50 or so protectors on the TV and some other
> equipment. The transformer that fed my house exploded during a storm.
> 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.

How do you tell a "good one"? We all know you can pay a lot and still get crap.

MOV surge protectors have little real value. Their main limitation is that they are consumed by doing their job and no longer protect anything. That may very well be why some events are protected from (the MOV is still intact) and some events allow damage to the gear (MOV was sacrificed previously, but no one knew).

"Surge" protectors are rated by the energy they protect against, but you have no way of knowing what level of protection you are going to need. Is it protection against an elephant? Or just a squirrel? Elephant guns cost a lot more than squirrel guns.

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On Monday, January 9, 2023 at 10:18:25 AM UTC-5, upsid...@downunder.com wrote:
> 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.
I wonder how they test them in production? Most likely, not at all. That would cost money.

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Rick C.

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On Monday, January 9, 2023 at 6:21:39 PM UTC-5, Don Y wrote:
> On 1/9/2023 7:52 AM, Ralph Mowery wrote:
> > The under say $ 20 strips are not very good.
> >
> > I had a couple of the $ 50 or so protectors on the TV and some other
> > equipment. The transformer that fed my house exploded during a storm.
> Do you have overhead power? Was the damage to the transformer due to
> a lightning strike?

Lightning strikes to the lines are very rare. Typically a surge is from the induced current of a nearby strike. Very different. It's nearly impossible to protect against the power of a direct strike to a line coming into the house. Protecting against induced surges is another thing.

> > 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?

If you have a direct strike on a home is going to start a fire and your TV will be your least worry.

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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

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.

quote:
"MOV surge protectors have little real value. Their main limitation is that
they are consumed by doing their job and no longer protect anything. That
may very well be why some events are protected from (the MOV is still
intact) and some events allow damage to the gear (MOV was sacrificed
previously, but no one knew). "

per this article:
....
www.electronicdesign.com/power-management/article/21800530/select-the-right-varistors-for-overvoltage-circuit-protection
....
the degradation is in the form of an leakage current. As the MOV is tied
across the 120VAC or 240VAC, the power dissipation increases, so
the body temperature increases, I wonder if this temp-rise is reliable enough
to detect with a few inexpensive parts and alert the owner of impending risk.

I always wondered if a third "sense" terminal would be of any value.
If the damage leads to a change in internal impedance, then
the change in AC voltage level from the sense terminal could be
detected.

On Wednesday, January 11, 2023 at 5:38:11 AM UTC-4, erichp...@hotmail.com wrote:
> 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.

Really? You think a $10 outlet strip is tested? lol

--

Rick C.

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