I do not dispute your references at all. All I stated was that was
what our employer required us to do. His inspectors even sent us back
to sights which failed their inspections.
We had several at the pitch of three story or greater apartment
buildings that were as long as the building is tall.
We were post wiring 12 to 50 unit structures.
This is all well and good, but does not change the fact of what they
had us doing. I am sure they have modified their practices since
I do not disagree.
I totally agree. Asshole installers from all involved walks of life
cut corners when the real work requisite faces them.
No shirt Shitlock.
I watched my cable internet speed drop overnight after a cable
installer "worked" inside our lockbox.
The original installer said my signal was GREAT. and my cable speed
reflected that 7Mb/s in and 0.5 out. After the "phone guy" changed
out the port taps in our lock box, I got 5Mb/s in, and was getting
failures on outgoing packets. I am sure the signal strength has
dropped, and would bet so. Now, it likely has spurs.
To this day it has never been the same, but Cox did "upgrade us
all", and now I get 10Mb/s in and my old 0.5 out, but it still hiccups
a lot on the out side, which is an ATM link, differing from the
incoming transport mechanism.
So I have seen where the cable co can screw up even one's "digital
reception" for one's internet link by no more than a few poorly cut
His problems, however, do point toward a house wiring issue, and
other did have the same feeling. Sure it is quite possible that it is
the cable co, but if they come out and read his attenuation level at
his end of line, and it is OK, then it is NOT the cable co. It COULD
be the cable modem.
Your position reveals a failure to train and supervise on the part of
Warner Amex CUBE system. The National Electric Code and all of the
local codes that are based on it requires that separate grounding
electrodes be bonded together into a single grounding electrode system.
Cable installers working on buildings rather than poles or hand holes
are not exempt from that requirement. Every one of those separate rods
is a destructive surge path waiting to happen.
Well we aren't no thin blue heroes and yet we aren't no blackguards to.
On Sat, 06 Jan 2007 22:15:29 GMT Thomas D. Horne, FF EMT
| JoeBloe wrote:
|> Gave us:|> |>> Verify that the ground block at the cable entry is connected to the |>> grounding system for the power. It can't (in the US) just be connected |>> to its own ground rod.|> |> |> Not true. We were REQUIRED to drive OUR OWN 8 ft rod whenever we|> did a post wire on an apartment complex. |> |> This was Time Warner (Warner Amex CUBE system at the time)|> |> Single home drops MAY be attached at the house tie point, or a ground|> rod CAN be driven. It is for lightning protection, and the problems|> being discussed in this thread are not related to that.|> |> That alone points toward the issue being with HIS power wiring, and|> NOT the cable system.
| Your position reveals a failure to train and supervise on the part of
| Warner Amex CUBE system. The National Electric Code and all of the
| local codes that are based on it requires that separate grounding
| electrodes be bonded together into a single grounding electrode system.
| Cable installers working on buildings rather than poles or hand holes
| are not exempt from that requirement. Every one of those separate rods
| is a destructive surge path waiting to happen.
I Agree 100% with Tom's position. I also have to admit that despite so
many other failures and lack of training among Comcast technicians or
their managers, and the company in general, this (connecting all the
ground rods solidly together) happens to be one thing they got right.
The previous cable system operator here didn't do it right, and that's
one of the things Comcast is working on now, for almost the entire
system, re-wiring every home to get the grounding correct. They are
just not putting enough manpower into it. But at least they know how
it's supposed to be wired.
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
It sounds like you might have a bad neutral (grounded conductor)
between the power company transformer and the power entrance into the
house. Either a bad connection or the wire itself is bad. That wire
carries current just like the "hot" wires do.
The current can't flow on the neutral so it's trying to follow your
coax instead. It's trying to flow back to the utility's transformer.
It's a dangerous condition if my guess is right. Time for an
electrician unless you're familiar with such things.
You might ask the electrician about a 4 wire service from the
utility's transformer to your house. It's a safer set up.
Yours is the post that makes the most sense to me. I'm not an
electrician, but if I understand correctly, the ground exists in case
there is a problem with the neutral - that way the current has a way
out other than through me or something else I don't want current
flowing through. So if the neutral is bad, the current is looking for
a way out, and some of it is finding the incoming coax when it's
connected and going out that way.
So assuming that the neutral could be bad, it could either be a bad
connection or wire inside my house, or could it be the feed from the
power company to my house? For obvious reasons, I'd prefer the power
company to come out and fix something outside my house rather than me
paying an electrician to fix something inside.
If it probably is inside my house, what would I look for in tracking it
down? It's in all the outlets, so it has to be at the main service
panel somehow, right? Making it either the power company's feed or
something bad inside the fuse box, if I'm guessing right.
Thanks alot for your help.
Not quite. The ground rods at a house are there mainly for
lightning protection. If the neutral (grounded conductor) between the
house and utility is bad, a bit of current can flow through the ground
rod, through the soil and back to the utility company's transformer.
Some could be flowing through your coax now. The rest could flow through
a person given the right circumstances. Current will flow through all
available conductors, not just the one with the least resistance.
That's why this could be dangerous.
More likely from the house to the utility. The neutral (grounded
conductor) and equipment ground are connected together in your panel.
All three wires going from the house to the utility actually carry
current. A problem downstream of your panel would probably cause a
light or something to not work. It shouldn't cause stray voltage
because the neutral and equipment ground are separate downstream of the
The problem might be the neutral connection as it enters the
panel. I would suggest not messing around in the main panel. It
would be too easy to make a mistake. There is also an arc or flash
hazard in addition to the electrocution hazard. I think burns cause
more injuries to electricians than the shocks do. My memory fails me
right now at what voltage the flash hazard starts.
Electricians are cheap compared to doctors. Good luck.
Measuring voltage cannot tell you where the electricity is coming
from. You know this. There is a 5 to 13 volt difference between cable
and AC electric. Why? This must not happen because cable and AC
electric must share a common earthing electrode. AC electric at the
mains breaker box and cable must be at 0 volts. Again, this because
cable shield and breaker box ground wire both meet at a common earthing
The purpose of that electrode serves many functions as defined by so
many. It is for safety from a failed neutral. For safety so that a
human is not electrically shocked. For surge protection.
Therefore inspect the cable where it enters the building. A
grounding block (or splitter) is wired to the earthing rod. A thicker
bare copper wire leaves breaker box to connect to that same earthing
Although not related to your problem, that earthing rod is solid
(cannot be shaken) and is 8 feet into earth. Put up on it and the rod
should not rise.
Cable cannot be earth via a water pipe (or faucet) connection. It
must be earthing where AC electric and telephone are also earthed; a
rod that you (or your agent the electrician or builder) should have
Now, implied is that voltage is in modem. Therefore you can measure
voltage between modem and cable center conductor? You can measure same
voltage from modem to cable shield connector? You can measure same
voltage from modem to ground screw on wall receptacle? You can measure
the same voltage from modem to cold water pipe? Based upon how I read
your posts, all reading should be that same voltage.
A bad neutral must not create the problem you are seeing because
(again) all three utilities (as demanded by code) must connect to the
same earthing electrode.
OK, let's say all utilities do connect to the same electrode. This
experiment is best done with an extension cord or some other long wire.
Measure voltage from modem direct to the earthing electrode. Does a
voltage exist? Do same from cable center conductor (the end that would
connect to modem) to earthing electrode. Any voltage? Cable shield to
electrode. Voltage? Grounding screw on wall receptacle to earthing
electrode. Voltage? In each case, no voltage (less than 1 volt)
should appear. For more thorough responses, list what each voltage
Back to that neutral wire problem. If problem exists, then
incandescent bulbs change intensity as major appliances power on and
Matt, one thing to consider is that your voltmeter may be reading RF rather
than AC particularly if it is a $3 drugstore special.
if this is the case there may be nothing intrinsically wrong with you house
wiring or grounding.
you might try repeating the measurements with a .01 uF (or thereabouts)
capacitor across the meter and see if it makes a difference.
if so a different approach may be called for.
i cannot speak for all cable installers, however the ones who wired one of
my facilities were completely and totally incompetent. it took many months
and many calls to get most of the issues resolved and the modems to be
generally reliable. after switching to TI and turning off cable life was
my recommendation is to politely but firmly and repeatedly insist on an
inspection by the "head end technician". this is what the cable industry
calls the chief engineer. with luck this will be an experienced and
knowledgeable individual armed with advanced test equipment. if he says
everything is OK from our end there is nothing more we can do then you can
procede with troubleshooting the house grounding/electrical system.
in the end you may have to use a 'cable ground loop isolator' but see what
the head end tech recomends first.
On 1/2/07 1:19 PM, in article
email@example.com, " firstname.lastname@example.org"
Without fully understanding your problem, I have some suggestions.
1. Run your modem power through an isolation transformer.
2. Run your signal through a line transformer.
That is, avoid your problems with multiple grounds rather than track them
-- Fermez le Bush
On 1/3/07 5:12 AM, in article email@example.com,
I cannot because I am not up on the subject. There certainly are broadband
(pulse) transformers available with much greater bandwidth than is required
for typical DSL. Transformer exist that use transmission line transformers
for high frequencies that simultaneously use iron cores to support low
-- Fermez le Bush
Chances are it's not your wiring and there's something wrong with at
the cable company or with their equipment. Here's a summary of the
problems I've encountered in the last few years:
I had a cousin who had a DSL problem. Her ISP said it was her computer.
I told her it wasn't and she probably had a bad modem. The problem went
on for weeks while they were giving her the run around. Finally she
called them and told them she was canceling her account. They came to
her house and replaced the modem and everything was fine.
I have an ex-son-in-law who's been going round and round with his cable
company for weeks because his television only worked good
sometimes--mostly at night. Actually, he had the same problem several
months before that and a serviceman had fixed it. Anyway they had him
trying everything and changing cables and promising someone would come
out, etc. When the serviceman finally arrived, he told him the problem
was because he was using RG-59 instead of RG-62, but actually it turned
out the signal coming into his apartment was too weak.
I used to have DSL and came home one day from my daughter's house after
a huge thunderstorm--one of the worst ones I've ever seen. Fortunately,
everything still worked because now days most equipment has built-in
surge protection. Everything still worked, that is, except my DSL
connection. Upon taking a close look at the modem, I noticed it lacked
a "CE" mark and, therefore, probably didn't have good surge protection.
My ISP had me jumping through hoops for 3 weeks talking to their
service center in India. Finally, a guy came out and replaced the
modem. By then, though, I was so damned mad I canceled the service and
went with a fiber optic connection. I had to buy my own modem, but they
gave me a recommended model number (a Wireless - B Linksys).
Everything worked fine for a couple of weeks until I decided to
download some music from Napster. Then I would always get disconnected
for some mysterious reason. I called my ISP and they told me to call
Napster. I did and Napster told me to contact my ISP (again). After
that my ISP ran some tests and said everything was fine, but of course
it wasn't. Finally, on about my 4th call a guy asked me what kind of
Modem I had and then told me I needed to switch to a Wireless - G
Linksys. That solved the problem.
Anyway, good luck. I hope you get it fixed soon.
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