Whole house surge suppressors

[Tom MacIntyre]

You are providing a great deal of misinformation to this
group, intentionally or not. A close lightning strike can
and WILL cause a large transient that can damage
electronic components. Please refrain from posting
until you have researched the subject thoroughly.

I have seen a horizontal yoke on a 27" TV arcing, which took out the
mainboard in the shop PC (8 or so feet away), and temporarily
scrambled the LED display on the Sencore oscilloscope nearby,
requiring it to be reset. A lightning strike would have much more
energy than that.

Tom

 

[Tom MacIntyre]

Hi

Maybe we should remove this thread from the A+ newsgroup. Although somewhat
interesting it is really not related to A+. You should start your own group,
Lightning and its effects.

Chris

Well, the first post was here, it's been here from the start, but it
appears that I am the only regular here who has been posting to the
thread.

Tom

 

[Tom MacIntyre]

A small van der graf generator producing a wimpy 50Kv can light
up fluorescent bulbs within a few feet. That sort of voltage
difference (at least 60-70 volts with enough current to produce
visible light) is ample to destroy electronics (ie: punch a hole
through a MOS gate).

There's an A+ question right there. I think the accepted answer is 30
volts.

Tom

 

[AG]

[snip]

The repairman (a different guy than last week) came out this morning and
said he talked to his supervisor and it's the customer's responsibility
to ground the NID (!) I pointed out that the ground connection is
inside the telco half of the box and customers don't have access to the
ground terminal. He said if the customer has a ground wire sticking out
of the wall when they install the NID they hook it up, otherwise they
leave it disconnected. He said the phone cable is low-voltage so the
national electric code doesn't apply -- the NFPA *thinks* it applies,
but Qwest has a lawsuit or something where they are challenging it.
Sounds like bullshit to me.

I didn't argue with the guy; I asked him if he could unscrew the box so
I could attach an earth wire without having to cut the box open. He
unscrewed the fancy-headed locking screw and showed me where to attach
the wire and to make sure I tighten the customer-side screw when I was
done to keep the weather out. I have a 1000' roll of #12 green wire
that I'll never use up, and I've fished the end of it through the siding
and exterior wall already. It'll take me less than 15 minutes to finish
the job this evening.

Next time I see my friend who's a supervisor at the city's building
safety office I think I'll mention this and see what he says. It's
disturbing that Qwest's policy is to install aerial phone lines without
earthing them at all. And I assume they only connect buried cable's
metal shield to the ground block and don't connect it to the building's
ground electrode system.

Best regards,
Bob

I had been hoping that this thread would die but DAMN that is STUPID. There
is a Telco ground at the pole on every one where their service comes off to
the house. I know I just about broke a lawnmower blade on one a few years
ago.
These guys are asking for a law suite when someone is killed by a lightning
strike and their on the phone.
AG

 

[Dbowey]

AG posted:

The repairman (a different guy than last week) came out this morning and
said he talked to his supervisor and it's the customer's responsibility
to ground the NID (!) I pointed out that the ground connection is
inside the telco half of the box and customers don't have access to the
ground terminal. He said if the customer has a ground wire sticking out
of the wall when they install the NID they hook it up, otherwise they
leave it disconnected. He said the phone cable is low-voltage so the
national electric code doesn't apply -- the NFPA *thinks* it applies,
but Qwest has a lawsuit or something where they are challenging it.
Sounds like bullshit to me.

I didn't argue with the guy; I asked him if he could unscrew the box so
I could attach an earth wire without having to cut the box open. He
unscrewed the fancy-headed locking screw and showed me where to attach
the wire and to make sure I tighten the customer-side screw when I was
done to keep the weather out. I have a 1000' roll of #12 green wire
that I'll never use up, and I've fished the end of it through the siding
and exterior wall already. It'll take me less than 15 minutes to finish
the job this evening.

Next time I see my friend who's a supervisor at the city's building
safety office I think I'll mention this and see what he says. It's
disturbing that Qwest's policy is to install aerial phone lines without
earthing them at all. And I assume they only connect buried cable's
metal shield to the ground block and don't connect it to the building's
ground electrode system.

If you will email me your phone number and what state you live in, I will talk
with the RIGHT person to get this resolved. We can post results here later if
you wish.

Don

 

[Chip Orange]

File a complaint with your state's public utilities commission.

 

[Bonehenge]

I had been hoping that this thread would die but DAMN that is STUPID. There
is a Telco ground at the pole on every one where their service comes off to
the house. I know I just about broke a lawnmower blade on one a few years
ago.

That ground is not connected to anyone's phone. Both conductors of a
POTS line are wired all the way back to a ground at the central office
or the closest piece of loop electronics, A.K.A "SLC". Grounds on
poles are for repeater cases, terminal cases, CATV, or the electric
company. Many times, they aren't grounds at all, but guy wires
supporting the pole.

These guys are asking for a law suite when someone is killed by a lightning
strike and their on the phone.

The phone co. side of the NID needs to be grounded for the lightning
protectors inside the NID to work. These devices shunt overvoltages
to ground, and open if an overcurrent condition exists. There is
similar equippage at the other end of the wire, where it connects to
the central office or loop electronics. The customer side of the NID
needs no lightning protection, as that side is past the point where
lightning would enter the premise. A lightning strike along the wire
would invoke the protection, which usually leaves the line either open
or grounded, until a repair person replaces the protector(s).

Be careful mowing the lawn.

Barry

 

[Louis Bybee]

AG posted:



If you will email me your phone number and what state you live in, I will talk
with the RIGHT person to get this resolved. We can post results here later if
you wish.

Don

Please do!

Thank you.

Louis--
*********************************************
Remove the two fish in address to respond

 

[w_tom]

From the FCC Part 68 Connection of Terminal Equipment to
the Telephone Network:

 

[w_tom]

So lightning enters the building on AC electric (black hot
wire) seeking earth ground. It arrives at those three MOVs
(called a plug-in surge protector) adjacent to a computer.
Now where does lightning go. Through an MOV to a spike in the
floor? That spike is not well connected to earth. Instead,
those MOVs shunt (distribute) that lightning strike to all AC
electric wires. More wires to seek earth ground,
destructively, through the adjacent computer.

Some possible paths from computer to earth ground - phone
line through modem; serial port cable where it drapes over
baseboard heat; or out via network card. These are all
potentially computer destructive paths because 1) a superior
and single point earth ground was not utilized at the service
entrance ('whole house' protector) and 2) because the spike in
a floor only labeled as ground does not make a conductive
connection to earth.

Chris Lewis's assumptions might be valid for normal mode
protection. And that is what Chris Lewis has assumed all
surges are:

... when there are large voltage differences between the
conductors entering a device.

But just like the plug-in protector manufacturers, Chris
forgets that typically destructive surges are common mode.
That means no voltage difference between wires while a
destructive voltage difference exists between ALL wires and
earth ground.
Therefore the 'spike labeled ground' accomplishes nothing
and leaves electronics exposed to destructive transients.

Aircraft grounding is completely different and more
complex. If one does not even understand normal and
longitudinal transients, then one has no right trying to
complicate the concepts by discussing aircraft. We are
discussing terrestrial structures and destructive transients.
Any discussion about aircraft only confuses the issue made
complicated enough when Chris does not even understand the
transient that is typically destructive. Instead he assumes a
transient is only a voltage between two wires. There are
other and typically more destructive types of transients. And
no place are we discussing helicopters.

 

[Chris Lewis]

So lightning enters the building on AC electric (black hot
wire) seeking earth ground. It arrives at those three MOVs
(called a plug-in surge protector) adjacent to a computer.
Now where does lightning go. Through an MOV to a spike in the
floor?

No, silly. Thru the ground wire to the ground.

Some possible paths from computer to earth ground - phone
line through modem; serial port cable where it drapes over
baseboard heat; or out via network card.

If you had bothered to _read_ my posting, you would have seen
I said "the conductors entering a device". Last I heard,
phone lines, and network cables were "conductors".

These are all
potentially computer destructive paths because 1) a superior
and single point earth ground was not utilized at the service
entrance ('whole house' protector)

That superior and single point earth ground _was_ utilized. It
just doesn't necessarily have a "whole house" protector on it.

Chris Lewis's assumptions might be valid for normal mode
protection. And that is what Chris Lewis has assumed all
surges are:
But just like the plug-in protector manufacturers, Chris
forgets that typically destructive surges are common mode.

You're not paying attention. "conductors entering a device"
means _all_ of them. Including the ground wire (if any).

That means no voltage difference between wires while a
destructive voltage difference exists between ALL wires and
earth ground.

It doesn't matter. If none of the conductors entering
a device have destructive voltage differences, there is
no danger.

 

[w_tom]

The assumption: a nail pounded in the floor that is a good
earth conductor, and all incoming conductor first connecting
to that nail. This system work assuming the building was
constructed to make that room a 'building within the
building'. Same technique is used in skyscrapers to make all
electronics on one floor protected. But the nail into a
wooden floor or a nail only inches into a concrete floor is
not sufficient protection. Good luck trying to retrofit that
room after the building is constructed. Yes, it can be
accomplished. Yes that nail firmly attached to a conductive
earth ground can also become the third layer of protection
(after primary utility and secondary 'whole house'
protection). But notice the numerous special considerations
that are required to make that system effective. Once we
apply reality, then a nail is not a good earth ground and not
everything entering the room can first connect to that nail.
Have you included the wall paint in your list of conductors?
That too must connect to the nail.

In my post, even the serial port cable from computer to
'nail' can easily compromise a protection system via a
conductor that is not connected to the nail - ie baseboard
heat. This complexity is why we, instead, install a simpler
protection system - the 'whole house' system with a short
distance to the superior earthing conductor and wire
separation to the electronics. That wire separation (between
room and central earth ground) becomes part of the protection
system that is simpler to install and more reliable.

In short, the 'nail in the floor' protection system is
subject to potential weaknesses made unnecessary by a 'whole
house' system and a superior building wide earthing system.
It can be accomplished, but only if additional complications
are first addressed.

The nail must not just be the center point junction. It
must also be the best conductor to earth ground in that room.
That made necessary by the compromises created by building
materials and standard construction practices.

Not only must the nail in the floor system be carefully
implemented, but the far less expensive 'whole house'
protector system and existing protection inside appliances
makes that nail redundant - an unnecessary expense.

 

[zxcvbob]

From the FCC Part 68 Connection of Terminal Equipment to the
Telephone Network:

I wrote to the local electrical inspector, explained the whole thing
(with a full orchestration and 5-part harmony and stuff like that) and
told him I was contacting him first because FCC Part 68 "Connection of
Terminal Equipment to the Telephone Network" gave him jurisdiction, and
this seemed like a dangerous public safety issue he needed to be aware
of. Here's his response:

The NID (network interface device) does not have gas discharge
devices, it is strictly a disconnecting means. The telephone company
is required, if you request, an accessible Network Interface Device.
The ground wire typically only protects the enclosure or the wire
sheathing, which in this case is plastic for the NID, and
non-existent in the drop. The exception would be if the aerial drop
to the property is using a messenger to carry the weight, most drops
do not use a messenger, the drop is actually tempered wire. Most
phone companies now protect the lines at the pole or at the
underground splice box at the edge of the property, not at the
entrance to the unit and it is not designed to protect your
equipment. Your conclusions about lightning damage are right on the
money. There is not inspection of utilities as they are regulated by
the Public Utilities Commission on a state level and the FCC on a
national level. The utilities will not hook up the ground if there
is not an accessible ground point adjacent to there equipment.

You are also correct about damage to your equipment from spikes and
lighting damage. Since the Telecommunication Act in the 1980’s it is
by and large your responsibility to provide your own protection of
your equipment on and in your property. There is some good
protection equipment on the market but it is not installed or
provided by the telephone company. There is some whole house
protection that may be available from an electrical or phone systems
contractor. Many will not know what you are talking about.

Maybe I should have included the "27 8x10 color glossy photographs, with
circles and arrows, and a paragraph on the back of each one, explaining
what each one was to be used as evidence..." (it's kind of scary that I
can quote old Arlo Guthrie material from memory)

Best regards,
Bob

 

[Steve Alexanderson]

The presence of the ground lug indicates that some type of arrester is
involved, even if it's just a gap. See
http://www.taunton.com/finehomebuilding/pdf/Lightning.pdf

He is right that his department and the NEC doesn't apply to utilities. The
code in question is the NESC, and among its requirements is one stating that
arresters that require grounding be grounded, and another stating that
accessible communication equipment subject to overvoltage be protected
against overvoltage.

 

[Floyd L. Davidson]

The presence of the ground lug indicates that some type of arrester is

As far as I know, that is *absolutely* correct.

involved, even if it's just a gap. See
http://www.taunton.com/finehomebuilding/pdf/Lightning.pdf
....

It does in fact have some form of surge protection.

That is not strictly true, though it nearly is. It does *not*
protect "the wire sheathing" in any case. It is true that it is
there to protect the telco equipment, and if that happens to
accidentally protect the customer's equipment, it is indeed just
and accident. The problem for the customer is that virtually
anything, other than a relatively old telephone, normally
connected to the line is going to be *much* more sensitive to
surges than the telco's equipment.

Which is to say the telco is not providing protection adequate
for modern customer equipment.

That is not true. There is often *no* protection, other than
properly grounding the cable sheath, at the point where the drop
is connected to the cable. That is more likely to be true with
aerial drops than with buried cable.

Yep.

....

Yep (several times over, as all of that is true).

Ack! You must be a commie!

 

[Dbowey]

zxcvbob posted:
<<

From the FCC Part 68 Connection of Terminal Equipment to the
Telephone Network:

I wrote to the local electrical inspector, explained the whole thing
(with a full orchestration and 5-part harmony and stuff like that) and
told him I was contacting him first because FCC Part 68 "Connection of
Terminal Equipment to the Telephone Network" gave him jurisdiction, and
this seemed like a dangerous public safety issue he needed to be aware
of. Here's his response:

The NID (network interface device) does not have gas discharge
devices, it is strictly a disconnecting means. The telephone company
is required, if you request, an accessible Network Interface Device.
The ground wire typically only protects the enclosure or the wire
sheathing, which in this case is plastic for the NID, and
non-existent in the drop. The exception would be if the aerial drop
to the property is using a messenger to carry the weight, most drops
do not use a messenger, the drop is actually tempered wire. Most
phone companies now protect the lines at the pole or at the
underground splice box at the edge of the property, not at the
entrance to the unit and it is not designed to protect your
equipment. Your conclusions about lightning damage are right on the
money. There is not inspection of utilities as they are regulated by
the Public Utilities Commission on a state level and the FCC on a
national level. The utilities will not hook up the ground if there
is not an accessible ground point adjacent to there equipment.

You are also correct about damage to your equipment from spikes and
lighting damage. Since the Telecommunication Act in the 1980’s it is
by and large your responsibility to provide your own protection of
your equipment on and in your property. There is some good
protection equipment on the market but it is not installed or
provided by the telephone company. There is some whole house
protection that may be available from an electrical or phone systems
contractor. Many will not know what you are talking about.

Maybe I should have included the "27 8x10 color glossy photographs, with
circles and arrows, and a paragraph on the back of each one, explaining
what each one was to be used as evidence..." (it's kind of scary that I
can quote old Arlo Guthrie material from memory)
Much of what the inspector said to you is either flat wrong, or is distorted
due to his/her lack of knowledge. I won't detail the pieces here.

QWEST, the object company of the OP post, in their Network Interface
disclosure, list three generic types of Network Interface Devices (NID) that
they use. Each one of these contains high-voltage protection elements,
requiring a ground connection. The ground wire connection is *required*. As I
recall, there are cases where the premises owner must provide the ground wire.

Willy-nilly speculation about the issue is not only counter-productive, it
leads to misunderstanding.

I volunteered to run this to the ground at QWEST, but the OP did not respond
with the info I would need to do it correctly. Lacking that support by the OP,
I believe this thread should die.

Don

 

[Chris Lewis]

The assumption: a nail pounded in the floor that is a good
earth conductor,

Stop there.

I've come to the conclusion that you're a computer program, generating
randomly perturbed iterations of the same misrepresentation at random times.

Noone has claimed that a nail pounded into the floor is a good earth
conductor.

Just that if all of the conductors into a device are OVP'd to a single
point, whether it be a real ground, a nail pounded into the floor (or
your head), or a wire splice in mid-air, protects that device from
voltage spikes.

Indeed, given standing wave effects, inductive/capacitive pickup,
and a whole host of other RF considerations, the _closer_ the OVP is
to the protected device, the better. It's called "minimizing the
effective antenna".

Or do I have to tell you the story about how moving the OVP 4 inches
along a conductor made all the difference between a microprocessor
fry and non-fry? Be careful what you wish for...

 

[ImhoTech]

Maybe I should have included the "27 8x10 color glossy photographs, with
circles and arrows, and a paragraph on the back of each one, explaining
what each one was to be used as evidence..." (it's kind of scary that I
can quote old Arlo Guthrie material from memory)

Best regards,
Bob

Nah...that part was one of the most interesting things posted here in a long
time. The fact that its from one of my 13 year old's favorite songs (for
about 3 years) is a bit scary..or not..heh.

 

[Mike Tomlinson]

a nail pounded into the floor (or
your head)

One can but hope.

 

[t gilb]

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