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Whole house surge suppressors

 
 
Mike Tomlinson
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Posts: n/a
 
      07-16-2004
In article <(E-Mail Removed)>, Chris Lewis
<(E-Mail Removed)> writes

>a nail pounded into the floor (or
>your head)


One can but hope.

--
A. Top posters.
Q. What's the most annoying thing on Usenet?

 
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daestrom
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Posts: n/a
 
      07-17-2004

"Steve Alexanderson"
<Idon'tlikegreeneggsandspamIdon'tlikethemsamIamsal (E-Mail Removed)>
wrote in message news:40f80155$(E-Mail Removed)...
> 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/finehomebuild.../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.
>

<snip>
> >
> > > 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.



Seems quite clear to me that the ground lug is only there to provide a
grounding for wire sheathing. The NID is meant to be used for wire that has
a metallic shield -or- a non-metallic cover. When a metal shielded cable or
support wire is used, it is connected to the ground lug of the NID and the
NID lug must be grounded. But if the phone drop does *not* use a support
wire or shielded cable, there is nothing connected to the ground lug inside
the NID. If you want to ground it, you are essentially running a ground
wire to a terminal that is connected to *nothing*.

Some may argue that having a grounded lug within an inch or so of the phone
wires provides *some* kind of protection by allowing direct lighning surges
to jump the small gap. But a voltage level needed to jump such a gap would
destroy all the phones in your house. And it would be much higher than the
protection devices at the pole would allow. So such a 'gap' argument is
silly as it is no protection at all.

Grounding the NID lug is only significant *if* the incoming phone drop uses
shielded wire or support wire that needs to be grounded. They don't have
internal surge-suppression/lightning protection. The use of the ground lug
varies from one phone company to the next. It even varies within the same
service area. The NID is designed for use with either type of phone drop
(one with a metallic shield or without). But like many devices, this
'feature' (the ground lug) isn't always used. It is only there for
grounding the shield or non-circuit metallic components. If you have
unshielded, tempered phone drop, there is no non-circuit metallic components
to ground.

daestrom


 
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w_tom
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Posts: n/a
 
      07-18-2004
This protector as defined in the 1997 Demarcation Point
Order was discussed in FCC Docket in 2000 in the paragraph
entitled "Safety Concerns Regarding the Placement of the
Demarcation Point Away from the Building". Petitioners were
AT&T, GTE, Southwestern Bell (SBC), and TIA. Concerned was
that, "locating the demarcation point a substantial distance
from the building in which telephone wire is located could
raise safety concerns."

Petitioners further noted "that the National Electrical Code
(NEC) requires the placement of surge protection at or near
the building, these petitioners concluded that if a network
protector is placed by the carrier at a demarcation point near
the property line, and that demarcation point is a significant
distance from the building, a second network protector should
be installed where the wire enters the building."

So what are they discussing if the protector does not exist
or is not required? The protector is required by code as
noted earlier AND the code even states how short a wire from
protector must be connected to earth ground. Even the FCC
states how close the protector must be to where wire enters
building.

daestrom wrote:
> Seems quite clear to me that the ground lug is only there to provide a
> grounding for wire sheathing. The NID is meant to be used for wire that has
> a metallic shield -or- a non-metallic cover. When a metal shielded cable or
> support wire is used, it is connected to the ground lug of the NID and the
> NID lug must be grounded. But if the phone drop does *not* use a support
> wire or shielded cable, there is nothing connected to the ground lug inside
> the NID. If you want to ground it, you are essentially running a ground
> wire to a terminal that is connected to *nothing*.
>
> Some may argue that having a grounded lug within an inch or so of the phone
> wires provides *some* kind of protection by allowing direct lighning surges
> to jump the small gap. But a voltage level needed to jump such a gap would
> destroy all the phones in your house. And it would be much higher than the
> protection devices at the pole would allow. So such a 'gap' argument is
> silly as it is no protection at all.
>
> Grounding the NID lug is only significant *if* the incoming phone drop uses
> shielded wire or support wire that needs to be grounded. They don't have
> internal surge-suppression/lightning protection. The use of the ground lug
> varies from one phone company to the next. It even varies within the same
> service area. The NID is designed for use with either type of phone drop
> (one with a metallic shield or without). But like many devices, this
> 'feature' (the ground lug) isn't always used. It is only there for
> grounding the shield or non-circuit metallic components. If you have
> unshielded, tempered phone drop, there is no non-circuit metallic components
> to ground.
>
> daestrom

 
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zxcvbob
Guest
Posts: n/a
 
      07-24-2004
w_tom wrote:
> This protector as defined in the 1997 Demarcation Point
> Order was discussed in FCC Docket in 2000 in the paragraph
> entitled "Safety Concerns Regarding the Placement of the
> Demarcation Point Away from the Building". Petitioners were
> AT&T, GTE, Southwestern Bell (SBC), and TIA. Concerned was
> that, "locating the demarcation point a substantial distance
> from the building in which telephone wire is located could
> raise safety concerns."
>
> Petitioners further noted "that the National Electrical Code
> (NEC) requires the placement of surge protection at or near
> the building, these petitioners concluded that if a network
> protector is placed by the carrier at a demarcation point near
> the property line, and that demarcation point is a significant
> distance from the building, a second network protector should
> be installed where the wire enters the building."
>
> So what are they discussing if the protector does not exist
> or is not required? The protector is required by code as
> noted earlier AND the code even states how short a wire from
> protector must be connected to earth ground. Even the FCC
> states how close the protector must be to where wire enters
> building.
>
> daestrom wrote:
>
>>Seems quite clear to me that the ground lug is only there to provide a
>>grounding for wire sheathing. The NID is meant to be used for wire that has
>>a metallic shield -or- a non-metallic cover. When a metal shielded cable or
>>support wire is used, it is connected to the ground lug of the NID and the
>>NID lug must be grounded. But if the phone drop does *not* use a support
>>wire or shielded cable, there is nothing connected to the ground lug inside
>>the NID. If you want to ground it, you are essentially running a ground
>>wire to a terminal that is connected to *nothing*.
>>
>>Some may argue that having a grounded lug within an inch or so of the phone
>>wires provides *some* kind of protection by allowing direct lighning surges
>>to jump the small gap. But a voltage level needed to jump such a gap would
>>destroy all the phones in your house. And it would be much higher than the
>>protection devices at the pole would allow. So such a 'gap' argument is
>>silly as it is no protection at all.
>>
>>Grounding the NID lug is only significant *if* the incoming phone drop uses
>>shielded wire or support wire that needs to be grounded. They don't have
>>internal surge-suppression/lightning protection. The use of the ground lug
>>varies from one phone company to the next. It even varies within the same
>>service area. The NID is designed for use with either type of phone drop
>>(one with a metallic shield or without). But like many devices, this
>>'feature' (the ground lug) isn't always used. It is only there for
>>grounding the shield or non-circuit metallic components. If you have
>>unshielded, tempered phone drop, there is no non-circuit metallic components
>>to ground.
>>
>>daestrom



Since the local building inspector agreed with the telephone company
(even though I quoted section 800 of the NEC in my letter), should I
just drop the issue? That's really not my style. Would I contact the
state building inspector or the public utilities commission or the FCC?

I suspect that none of them will want to get involved.

Thanks again,
Bob
 
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Floyd L. Davidson
Guest
Posts: n/a
 
      07-24-2004
zxcvbob <(E-Mail Removed)> wrote:
>
>Since the local building inspector agreed with the telephone
>company (even though I quoted section 800 of the NEC in my
>letter), should I just drop the issue? That's really not my
>style. Would I contact the state building inspector or the
>public utilities commission or the FCC?
>
>I suspect that none of them will want to get involved.
>
>Thanks again,
>Bob


Your suspicions are probably correct.

The FCC has nothing to do with it, so the state building
inspector and the public utilities commission are your only
choices.

I'm not sure I see much point in doing that.

I don't recall now just what the original interaction with the
telco was, but the *first* thing one wants to do is thoroughly
exhaust all avenues with the telco. I seem to recall it was one
outside plant installer with an imagination who conjured up a
story that was total bullshit, but to him sounded pretty good,
that was the last contact?

You need to discuss this with supervisors and engineers, and
make repeated efforts at it, until you have nobody else you can
pester. Keep logs of *exactly* who you talk to (the date, the
time, and who they are and a short description of what they
say). And make it obvious that you are keeping track too (they
are also logging it, so don't worry about upsetting anyone).

As long as you get unsatisfactory answers, demand to speak to
someone who has more knowledge or authority. Be courteous,
professional, and do not bluff anyone with anything.

If you get to the point where you've talked to everyone who is
anyone, *then* take the entire log to the PUC. What happens at
that point depends very much on where you are. Some regulatory
agencies are virtual rubber stamps, and will do *nothing*.
Others will demand a _certified_ response from the telco
guaranteeing that no rule or regulation is going to continue to
be broken. (If you are the first, nothing else happens; but if
they just certified the same thing six months ago, all Hell will
break loose.)

At no point do you want to hold your breath waiting for
justice...

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) http://www.velocityreviews.com/forums/(E-Mail Removed)
 
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MC
Guest
Posts: n/a
 
      08-05-2004
Had an unterminated arial phone line running parallel below power lines for
about 300 feet. Did not know was not connected, went to investigate open end
dangling on power pole and got knocked off my feet!

I never ran across this on short runs and most are terminated on one end or
the other so did not think to check things out first.

Anyway did not have a meter with at the time to see what the potential was ?
I wonder how much current could be sinked from that source ?
If I ever get a chance to find another situation like that, think I will do
some testing to see.



"Chris Lewis" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> According to w_tom <(E-Mail Removed)>:
> > We knock down that field generated voltage with an NE-2 neon
> > glow lamp because the current associated with a long wire
> > antenna (ie telephone line) is quite small. I ask this
> > question repeatedly and never receive appropriate numbers.
> > Where is the massive current from a long wire antenna that is
> > not and cannot be earthed by telco's 'whole house'
> > protector? If the long telephone wire creates a massive
> > surge, then what are the numbers that overwhelm a protector?

>
> You don't seem to understand RF frequencies very well. At the slew rates
> and frequencies present in lightning strikes, you can very easily
> have the ends of a few feet of wire at potential differences
> of thousands of volts.
>
> Heck, we routinely see people in this newsgroup using high impedance
> DVMs reading dozens of volts on disconnected wires simply thru
> inductive/capacitive effects from adjacent line power. Even the 62V
> someone reported yesterday would be enough to destroy some semi-conductor
> circuitry. Imagine what those voltages would be like during a nearby

strike.
>
> A house is equivalent to a coil, with many separate windings.
> Some effectively grounded at both ends, some at one end, and some
> not at all. A nearby lightning strike can induce thousands of volts
> onto some of those "windings", grounded or otherwise.
>
> Indeed, the field generated voltage that a NE-2 glowlamp shorts out
> (60-90V) _is_ high enough to destroy some electronics.
>
> Even if your house is protected with a whole-house filter, an induced
> voltage on the house wiring can destroy "nearby" electronics _before_
> the overvoltage even gets to the whole-house filter. Read up on
> slew rates and cable impedance.
>
> > I can appreciate the theory of electromagnetically generated
> > transients. Now lets see numbers applied to that theory.
> > Experience repeatedly says the direct strike is so
> > destructive. If nearby strikes were so destructive, then car
> > radios would often be damaged due to nearby strikes. Radios
> > designed to concentrate electromagnetic fields onto sensitive,
> > low voltage RF transistors are still not damaged by
> > lightning's electromagnetic fields.

>
> Radios use low impedance devices (ie: bipolar transistors) on their
> front ends with lots of effective grounding for high voltage yet
> low amperage transients (ie: shunt coils, caps etc). If they were
> FET semiconductors with no upstream circuitry/shunts, it'd be a
> whole different ballgame. They go poof if a dry cat brushes by
> the antenna. Computer input circuitry is more like that than
> radio input circuitry.
> --
> Chris Lewis, Una confibula non set est
> It's not just anyone who gets a Starship Cruiser class named after them.



 
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Beachcomber
Guest
Posts: n/a
 
      08-05-2004
On Wed, 4 Aug 2004 21:05:34 -0400, "MC" <(E-Mail Removed)> wrote:

>Had an unterminated arial phone line running parallel below power lines for
>about 300 feet. Did not know was not connected, went to investigate open end
>dangling on power pole and got knocked off my feet!
>
>I never ran across this on short runs and most are terminated on one end or
>the other so did not think to check things out first.
>
>Anyway did not have a meter with at the time to see what the potential was ?
>I wonder how much current could be sinked from that source ?
>If I ever get a chance to find another situation like that, think I will do
>some testing to see.
>
>

In some very remote parts of the world, parallel conductors are run
for moderate distances along the right-of-way of high voltage
transmission lines. The small amount of power from this linear,
inductive tap is used to feed the power needs of small villages.

Apparently, this is a cost-effective alternative to a substation.

Beachcomber


 
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Chris Lewis
Guest
Posts: n/a
 
      08-05-2004
According to MC <(E-Mail Removed)>:
> Had an unterminated arial phone line running parallel below power lines for
> about 300 feet. Did not know was not connected, went to investigate open end
> dangling on power pole and got knocked off my feet!


> I never ran across this on short runs and most are terminated on one end or
> the other so did not think to check things out first.


> Anyway did not have a meter with at the time to see what the potential was ?
> I wonder how much current could be sinked from that source ?
> If I ever get a chance to find another situation like that, think I will do
> some testing to see.


The above is probably not related to my previous comments about induced
voltages.

An open (on hook) telco circuit often has, if I recall correctly, about 48VDC
on it. Not a lot of amps (it's only 26ga or so after all...).

When the phone rings, you're getting AC at 90V or even more. Which is why
the old telephone set bell units work so nicely on 120V. It's close-enough
voltage matched to ring without frying anything. Similarly, not much in the
way of amperage.

All the above means is that you can get a pretty compelling zap when you touch
one depending on how well you're grounded. Ie: an extra line drop that's
connected but not currently being used.

As I demonstrated to myself a few months ago after trying to splice an accidentally
severed phone wire while sitting on bare concrete... Not lethal this time,
but strong enough to make it impossible to ignore. The SO could hear me cursing
150' away thru two exterior walls

But, remember, under certain (albeit rare) circumstances, even 48V can be lethal.

That said, it is entirely possible that a phone line can become energized
to much higher potentials.

There's a story that went thru this group years ago about having phone
service to an area in the US failing, and phone service people finding
two smoking dead bodies underneath a severed phone trunk line.

There was a moderately high resistance power fault from a nearby HV
feeder into the trunk grounding sheath that was grounded well enough at
the other end of the trunk to not present phone problems, and the fault
wasn't big enough to trip the HV feeder's interrupter either.

Two thieves tried to steal the phone trunk cable (for copper scrap).
When they severed the cable and touched the trunk grounding sheath,
_they_ became the grounding path. They weren't as robust as the
grounding at the other end of the severed trunk line...

So, it pays to be very cautious about wires hanging down from power
poles, no matter what they look like.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
 
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Tom MacIntyre
Guest
Posts: n/a
 
      08-05-2004
On Thu, 05 Aug 2004 17:45:44 GMT, Michael <(E-Mail Removed)> wrote:

>Chris Lewis wrote:
>
>> The above is probably not related to my previous comments about induced
>> voltages.
>>
>> An open (on hook) telco circuit often has, if I recall correctly, about 48VDC
>> on it. Not a lot of amps (it's only 26ga or so after all...).
>>
>> When the phone rings, you're getting AC at 90V or even more.

>
>Yeah I got zapped when I was a kid. I'd rip electronics open and tinker
>with the circuitry. One day playing with a phone, a call must have come
>in and hit me with 90 volts. It was more of unexpected shock than any
>real pain. Had to be 90 V AC ring voltage cause I could feel the
>alternations versus 48 V DC. Funny thing is the phones didn't ring, I
>must have somehow sinked enough juice.
>
>On unterminated long wire antennas (and Beverages?) you can accumulate
>enough "static" charge to zap someone. Distant lightning storms or
>whatever cause this.
>
>michael


A friend brought an old crank generator/magneto in to school one day.
A bunch of us less sane ones (all male, of course) tooks turns giving
and receiving zaps. Remember Bob and Doug MacKenzie in "Strange Brew",
fighting over who would receive the electric shock therapy while in
the mental institution? Like that.

Tom
 
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Pop Rivet
Guest
Posts: n/a
 
      08-07-2004
Please set followups to your favorite group!
It's silly to cross post to so many groups, especially in
light of the misinformation presented here. Please refrain
from doing so in the future and become a good netizen.

You can look up any of the following at about any telco:
they're all onine.
Nor North America, Canada, Japan and a few other countries:
-- Ring Voltages: 70Vrms to 90Vrms, NOT 90V "or more".
The actual voltage will depend on the REN loading AND
distance from the telco where the ring generator is located,
plus any amplifiers in the line along the way to the
subscriber. If it cannot leave the telco at >90Vrms, be FCC
spec, it will never exceed that voltage anywhere along the
line.
-- Ring Voltage Current: Up to 100 mA by spec, on a short
line, up to 120mA emergency power. It IS LETHAL!
-- Ring Voltage Frequency: 20, 25, 30, 33, or 50 Hz,
+/-5Hz. Most of the US uses 20 Hz +/- 5 Hz and most
electronic telephone equipment is rated Class B, meaing it
will detect ANY ringing frequency that is to spec. Cheapie
crap only responds to about 12 to 28 Hz in my experience.
-- Ring Voltage Pattern: Normally 2 S on, 4 S off,
repeated. Other patterns widely used for special services.

Pop
---
Those who have nothing to say often say so.



"Alan Stiver, PE" <(E-Mail Removed)> wrote in
message news:41140c49$(E-Mail Removed)...
> And telephone ring voltage frequency is usually 20Hz,

which is almost
> low enough to count the cycles. Hurts, especially if you

accidentally
> get your ear close enough to a connecting block. A guy I

work with was
> stripping a piece of phone wire WITH HIS TEETH!! a couple

of years ago
> when someone rang that line. He'll never live that one

down!
>
> Chris Lewis wrote:
>
> >
> > When the phone rings, you're getting AC at 90V or even

more.
>
>
>
> -----= Posted via Newsfeeds.Com, Uncensored Usenet News

=-----
> http://www.newsfeeds.com - The #1 Newsgroup Service in the

World!
> -----== Over 100,000 Newsgroups - 19 Different Servers!

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