| Author |
Message |
11
Guest
|
 Posted:
Thu Feb 10, 2005 6:18 pm Post subject:
problem between power and communication cable |
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I have problem with access to internet.
My line card (modem) was several times burned out.
Maybe the problem is because of EMC between power and communication cable.
Please, tell me does the communication cable from computer to
telecommunication outlet must be separated from
power cable Computer-electrical outlet (and power cable of heating system
2 kW), what is max. length of this cable, what safety instruction must we
made. And according to what standard.
Thanks.
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Dale Farmer
Guest
|
| Posted:
Thu Feb 10, 2005 10:38 pm Post subject:
Re: problem between power and communication cable |
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11 wrote:
| Quote: | I have problem with access to internet.
My line card (modem) was several times burned out.
Maybe the problem is because of EMC between power and communication cable.
Please, tell me does the communication cable from computer to
telecommunication outlet must be separated from
power cable Computer-electrical outlet (and power cable of heating system
2 kW), what is max. length of this cable, what safety instruction must we
made. And according to what standard.
|
Buy a good grade of UPS with good power protection in it. Run the phone
line through the provided phoneline jacks on it. Burning out of modems is
usually from nearby lightning strikes. Replace the surge suppresser annually,
as the protection devices get used up.
--Dale |
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Lucas Tam
Guest
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| Posted:
Fri Feb 11, 2005 1:26 am Post subject:
Re: problem between power and communication cable |
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Dale Farmer <dale@cybercom.net> wrote in news:420B9C51.97255903
@cybercom.net:
| Quote: | Replace the surge suppresser annually,
as the protection devices get used up.
|
Or just buy a non MOV based surge protector (more expensive, but they won't
wear out).
--
Lucas Tam (REMOVEnntp@rogers.com)
Please delete "REMOVE" from the e-mail address when replying.
http://members.ebay.com/aboutme/coolspot18/ |
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w_tom
Guest
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| Posted:
Fri Feb 11, 2005 2:21 am Post subject:
Re: problem between power and communication cable |
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|
Other responders have assumed a myth: "surge protector =
surge protection". They have assumed a protector will stop,
block, or absorb transients. For generations, such solutions
have never been effective. Generations ago, we routinely
suffer no damage because we don't even try to stop, block, or
absorb transients. We use what Ben Franklin demonstrated in
1752.
Protection is not the protector. Protection is earth
ground. A protector is effective IF it connects a transient
'less than 10 feet' to the protection - earth ground. Those
other recommendations don't even discuss earthing. Rather
embarrassing.
A figure from the NIST (National Institute of Standards and
Technology) may demonstrate your problem. The fax machine is
damaged because protection is not properly located and
installed:
http://www.epri-peac.com/tutorials/sol01tut.html
Protection is not those protectors - power strip or UPS. In
the NIST figure, the protection on each incoming utility wire
is not the same single point earth ground. That single point
is one essential requirement of effective protection. Every
incoming utility wire (including communication and power -
whether buried or overhead) must enter a building earthed to a
single point. An earthing connection must be via surge
protector (AC electric and phone) or using a hardwire (CATV
which requires no surge protector to make that connection).
Phone lines typically have a 'whole house' protector
installed for free by the telco. Why? 'Whole house'
protectors are so inexpensive and so effective. But that
'whole house' protector - again - will only be as effective as
the earth ground provided by your building. That NIST figure
demonstrates why.
If all incoming utilities are earthed (via protector or hard
wire) to the single point earthing point, then no voltage
gradient exists inside your line card to cause damage. If all
inputs are raised to 10,000 volts simultaneously, then there
is no voltage transient to damage transistors.
Again, we don't stop, block, or absorb surges - such as that
UPS recommendation implies. How would that UPS stop what
miles of sky could not? It's manufacturer does not even claim
that ability. He simply hopes others will promote a myth -
that the plug-in UPS provides protection from the other
typically destructive transient. Create equipotential so that
the line card is not damaged. Plug-in protectors cannot do
that.
The most common source of modem damage is AC electric. In
fact a most common damaged part is the PNP transistor that
drives the off hook relay. Why? The PNP transistor conducts
the transient when both AC electric and phone line are not
earthed to the same single point earth ground. Others who did
not learn how damage occurs will still recommend useless
plug-in protectors.
Again, phone lines already have an effective 'whole house'
protector. But AC electric is the one utility that connects
wires highest on the utility pole (most often struck) directly
into modem. Furthermore, an adjacent protector can even make
this damage easier.
CATV and phone lines already (should) have effective
earthing connections as even required by National Electrical
Code (you should verify this). But AC electric is not
required to provide transistor protection. The homeowner must
install a 'whole house' protector on AC mains (at a cost of
less than $1 per protected appliance). Numerous 'whole house'
protectors are available from Leviton, Siemens, Square D,
Furse, etc. One is sold in Home Depot is Intermatic IG1240RC.
No effective protectors are sold in Lowes, Sears, Kmart,
Walmart, Staples, Office Max, etc. How do you know? Two
simple rules: 1) the protector does not have a dedicated
connection to earth ground AND 2) the manufacturer (ie that
recommended UPS) does not even discuss essential earthing.
The bottom line: A surge protector is only as effective as
its earth ground. No earth ground means no effective
protection. Modem damage is so easily avoided as to be
considered directly traceable to human failure - such as those
who recommend plug-in protectors.
11 wrote:
| Quote: | I have problem with access to internet.
My line card (modem) was several times burned out.
Maybe the problem is because of EMC between power and communication
cable. Please, tell me does the communication cable from computer
to telecommunication outlet must be separated from power cable
Computer-electrical outlet (and power cable of heating system
2 kW), what is max. length of this cable, what safety instruction
must we made. And according to what standard. |
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Watson A.Name - \"Watt Su
Guest
|
| Posted:
Sun Feb 13, 2005 5:07 am Post subject:
Re: problem between power and communication cable |
|
|
"Dale Farmer" <dale@cybercom.net> wrote in message
news:420B9C51.97255903@cybercom.net...
| Quote: |
11 wrote:
I have problem with access to internet.
My line card (modem) was several times burned out.
Maybe the problem is because of EMC between power and communication
cable.
Please, tell me does the communication cable from computer to
telecommunication outlet must be separated from
power cable Computer-electrical outlet (and power cable of heating
system
2 kW), what is max. length of this cable, what safety instruction
must we
made. And according to what standard.
Buy a good grade of UPS with good power protection in it. Run the
phone
line through the provided phoneline jacks on it. Burning out of
modems is
usually from nearby lightning strikes. Replace the surge suppresser
annually,
as the protection devices get used up.
|
Hah-hah-hah! Used up! That's like the guy at MIT who borrowed the
screwdriver, and shorted out a bus bar in the computer with it, taking a
bite-sized chunk out of its blade when it arced. When he brought it
back, he said it was "used up"! :-P
> --Dale |
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Watson A.Name - \"Watt Su
Guest
|
| Posted:
Sun Feb 13, 2005 5:09 am Post subject:
Re: problem between power and communication cable |
|
|
"Lucas Tam" <REMOVEnntp@rogers.com> wrote in message
news:Xns95F99D01CD48Cnntprogerscom@140.99.99.130...
| Quote: | Dale Farmer <dale@cybercom.net> wrote in news:420B9C51.97255903
@cybercom.net:
Replace the surge suppresser annually,
as the protection devices get used up.
Or just buy a non MOV based surge protector (more expensive, but they
won't
wear out).
|
Or better yet, don't waste your money on ineffective surge protectors
that are built into the power strips. They depend on an excellent
ground, which most dwellings don't have. Put the surge protector on the
main breaker panel where it belongs. That's where the lightning surges
come from.
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Watson A.Name - \"Watt Su
Guest
|
| Posted:
Sun Feb 13, 2005 5:26 am Post subject:
Re: problem between power and communication cable |
|
|
"w_tom" <w_tom1@hotmail.com> wrote in message
news:420BD059.2299ED11@hotmail.com...
| Quote: | Other responders have assumed a myth: "surge protector =
surge protection". They have assumed a protector will stop,
block, or absorb transients.
[snip] |
| Quote: | Others who did
not learn how damage occurs will still recommend useless
plug-in protectors.
|
I'll agree with that 100 percent!
[snip]
| Quote: | The bottom line: A surge protector is only as effective as
its earth ground. No earth ground means no effective
protection. Modem damage is so easily avoided as to be
considered directly traceable to human failure - such as those
who recommend plug-in protectors.
|
I've just removed some of his verbiage that tends to turn people off
after reading the first sentence.
Bottom line is that the $3 power strip with 50 cents of worthless parts
in it, sold as a $30 to $50 surge protector, is _pure_profit_ for those
radio scrap and best buy stores out there that sell you one of those
with your computer system.
| Quote: | 11 wrote:
I have problem with access to internet.
My line card (modem) was several times burned out.
Maybe the problem is because of EMC between power and communication
cable. Please, tell me does the communication cable from computer
to telecommunication outlet must be separated from power cable
Computer-electrical outlet (and power cable of heating system
2 kW), what is max. length of this cable, what safety instruction
must we made. And according to what standard. |
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