bad ground = phone hum?

[[email protected]]

There is a heavy wire running from the outside phone box (company side)
to a big spike in the ground. I clipped that with hedge clippers some
years ago, then I repaired the break merely by twisting the ends back
together and that worked okay for many years..

Today there is a bad, constant hum on all phones. When I plugged a
phone into the outside box jack, the hum was the same. It has also been
raining for several days.

Can a bad ground cause a hum? Vigorously shaking the ground wire caused
no static. What should I expect if I disconnected the ground entirely?
(As I write this, I'm thinking maybe with corrosion the path to ground
is now non-existent.)

Also, there was a wasp nest in the customer side of the outside box
(but not in the company side). The nest didn't seem to create any
obvious destruction, though. If I connect a phone to the jack on the
customer side, then the nest seems to have no involvement anyway since
the terminals on that side become irrelevant - but you never know.

 

[Dr. Anton T. Squeegee]

There is a heavy wire running from the outside phone box (company side)
to a big spike in the ground. I clipped that with hedge clippers some
years ago, then I repaired the break merely by twisting the ends back
together and that worked okay for many years..

Not good. At the very least, you need to use an appropriate wire
nut rated for outdoor use. Simply twisting the ends together is not
enough.

Today there is a bad, constant hum on all phones. When I plugged a
phone into the outside box jack, the hum was the same. It has also been
raining for several days.

Can a bad ground cause a hum? Vigorously shaking the ground wire caused

Not quite. What CAN cause the hum you describe is a partial ground
on one side or the other of the line. Since the noise is present
directly at the box, you need to call your local phone company to make
repairs.

no static. What should I expect if I disconnected the ground entirely?

NO! NONONONONONONONOOOO!!!! Let the phone co. re-do the ground.
Disconnecting it and leaving it that way is a violation of Natl.
Electrical Code, and can get you in dutch with the telco if they find
out you had an accident with it with your hedge trimmer.

Best thing to do is simply get your telco repair person out.
They'll see the ground, but you can simply say something like "Huh?
What's a 'ground wire?'" and they have no way to prove you messed with
it. They'll fix it, along with your hum problem, and all should be well.

Also, there was a wasp nest in the customer side of the outside box
(but not in the company side). The nest didn't seem to create any
obvious destruction, though. If I connect a phone to the jack on the
customer side, then the nest seems to have no involvement anyway since
the terminals on that side become irrelevant - but you never know.

Warn the tech about that before s/he starts work. The nest may be
dead at this point (it is, after all, getting into winter), but they
appreciate knowing about such things.

Keep the peace(es).

 

[Alan 'A.J.' Franzman]

There is a heavy wire running from the outside phone box (company side)
to a big spike in the ground. I clipped that with hedge clippers some
years ago, then I repaired the break merely by twisting the ends back
together and that worked okay for many years..

Today there is a bad, constant hum on all phones. When I plugged a
phone into the outside box jack, the hum was the same. It has also been
raining for several days.

Can a bad ground cause a hum? Vigorously shaking the ground wire caused
no static. What should I expect if I disconnected the ground entirely?
(As I write this, I'm thinking maybe with corrosion the path to ground
is now non-existent.)

Also, there was a wasp nest in the customer side of the outside box
(but not in the company side). The nest didn't seem to create any
obvious destruction, though. If I connect a phone to the jack on the
customer side, then the nest seems to have no involvement anyway since
the terminals on that side become irrelevant - but you never know.

Phone lines are not (supposed to be) grounded, and generally are not shielded
either - being run as twisted pairs is all the noise protection they usually
need. The ground wire you cut is for lightning protection.

When you tested at the customer-side jack in the NID (Network Interface
Device) box and still heard hum, was this with all lines leading into the
house disconnected? (Usually the same jack that you tested at will have a
plug in it that connects/disconnects all inside lines.) If not, check it
again with inside lines disconnected and see if that makes a difference. If
disconnecting your house lines doesn't clear up the hum, it's the phone
company's problem.

--
--------------------

Alan "A.J." Franzman

Email: a.j.franzman [ A T ] verizon [ D O T ] net

--------------------

 

[Ross Herbert]

There is a heavy wire running from the outside phone box (company side)
to a big spike in the ground. I clipped that with hedge clippers some
years ago, then I repaired the break merely by twisting the ends back
together and that worked okay for many years..

Today there is a bad, constant hum on all phones. When I plugged a
phone into the outside box jack, the hum was the same. It has also been
raining for several days.

Can a bad ground cause a hum? Vigorously shaking the ground wire caused
no static. What should I expect if I disconnected the ground entirely?
(As I write this, I'm thinking maybe with corrosion the path to ground
is now non-existent.)

Also, there was a wasp nest in the customer side of the outside box
(but not in the company side). The nest didn't seem to create any
obvious destruction, though. If I connect a phone to the jack on the
customer side, then the nest seems to have no involvement anyway since
the terminals on that side become irrelevant - but you never know.

The 'ground' connection is most likely associated with a lightning
surge protection device if you are in an area prone to lightning. In
normal circumstances a phone line which isn't prone to lightning will
not have a lightning protector and therefore no 'ground' connection.
It is simply a 'protective ground' for this purpose.

Having said that, if there is a protector and it has received a
'splat', it may have broken down and caused one or both legs of the
telephone line to become low insulation to earth, which will cause hum
on your line.

If there is a protector I would try disconnecting it (temporarily) so
that the incoming line pair is connected straight through to the
phone. If hum is still present then you need to do some further
analysis since the fault could be internal to your house telephone
wiring or external to the house in the incoming telco cable. If you
can disconnect your internal cabling from the external cabling jury
rig your phone instrument to the incoming telco pair and then see if
the hum is still present. If it is then the fault is either in your
instrument or in the telco line. Only a known good instrument (or
buttinski) will determine which of the latter two cases it is.

Of course, you may not be allowed to play with your telephone cabling
depending upon your telco regulations so I leave it up to you to
determine. After testing is completed make sure that you restore
everything to the way it was or you might incur the wrath of the telco
if you weren't supposed to be playing with the line.

 

[w_tom]

As others have noted, grey telephone box (NID) contains a surge
protector that is effective if earthing connection exists. Phone will
work with or without earthing wire. But without that wire, then human
and transistors are both at risk and phone installation violates code.
Telephone installations must have that 'whole house' type protector and
earthing. Earthing wire must be continuous, no splices, not bundled
with other wires, short (ie 'less than 10 feet'), and connected to same
earthing electrode used by AC electric and cable company ground wire.
As others noted, you want that earthing wire corrected - and without a
splice.

Hum may be from a partially damaged surge protector inside NID.
Determine whether hum is inside house or in NID box. By doing as Alan
has recommended, open 'Customer access' side where your wire connects
to their box via RJ11 phone plug. Simply disconnect your wire and plug
a telephone directly into that phone jack. If hum is heard, then
problem is on telco and they pay. Otherwise problem is on your wires
and you pay (or fix it yourself).

That 10 AWG earthing wire (they are responsible for it) must be
fixed. But first determine where problem exists - on your side or
theirs.

 

[[email protected]]

As others have noted, grey telephone box (NID) contains a surge
protector that is effective if earthing connection exists. Phone will
work with or without earthing wire. But without that wire, then human
and transistors are both at risk and phone installation violates code.
Telephone installations must have that 'whole house' type protector and
earthing. Earthing wire must be continuous, no splices, not bundled
with other wires, short (ie 'less than 10 feet'), and connected to same
earthing electrode used by AC electric and cable company ground wire.
As others noted, you want that earthing wire corrected - and without a
splice.

Hum may be from a partially damaged surge protector inside NID.
Determine whether hum is inside house or in NID box. By doing as Alan
has recommended, open 'Customer access' side where your wire connects
to their box via RJ11 phone plug. Simply disconnect your wire and plug
a telephone directly into that phone jack. If hum is heard, then
problem is on telco and they pay. Otherwise problem is on your wires
and you pay (or fix it yourself).

Thanks to all who replied. I did do as you say, on the first day. The
hum was the same when plugged into the NID. I called the telco while
outside in the drizzle, and still plugged into that NID jack. The
customer rep told me that someone would arrive the next day, and if
they plugged into the outside jack and there was no hum, I'd get
charged $99 for the visit. I said that the problem might be gone the
next day, which was forecasted to be dry and sunny - so I told her not
to send anybody.

That decision saved me the $99. By 11am the next day, the hum was gone.
But the day after that was rainy again, and the hum was back. I
disconnected and reconnected the ground, which had no effect
whatsoever. Next, I fiddled with the wires inside the NID. Then the
phone was clear. A half hour later, the hum was back. I removed the
plug and sprayed electronic cleaner into the jack. (Note that wasps had
made a nest inside, since abandoned - but there could be some fine
organic material all over.) The noise came and went with no rhyme or
reason on that day, but was gone the following day.

There have been some slight rains since, with no hum. I guess I have to
wait for bad rains, and try to schedule a visit while it is still in
the rain period. It's a crap shoot.

In the meantime, where could I get the exact same grey wire that the
telco uses for ground?
I don't want to one day have them show up and charge me a small fortune
to redo it. Thanks.

 

[jakdedert]

Thanks to all who replied. I did do as you say, on the first day. The
hum was the same when plugged into the NID. I called the telco while
outside in the drizzle, and still plugged into that NID jack. The
customer rep told me that someone would arrive the next day, and if
they plugged into the outside jack and there was no hum, I'd get
charged $99 for the visit. I said that the problem might be gone the
next day, which was forecasted to be dry and sunny - so I told her not
to send anybody.

That decision saved me the $99. By 11am the next day, the hum was gone.
But the day after that was rainy again, and the hum was back. I
disconnected and reconnected the ground, which had no effect
whatsoever. Next, I fiddled with the wires inside the NID. Then the
phone was clear. A half hour later, the hum was back. I removed the
plug and sprayed electronic cleaner into the jack. (Note that wasps had
made a nest inside, since abandoned - but there could be some fine
organic material all over.) The noise came and went with no rhyme or
reason on that day, but was gone the following day.

There have been some slight rains since, with no hum. I guess I have to
wait for bad rains, and try to schedule a visit while it is still in
the rain period. It's a crap shoot.

In the meantime, where could I get the exact same grey wire that the
telco uses for ground?
I don't want to one day have them show up and charge me a small fortune
to redo it. Thanks.

I had a problem last week with my NID. Water got inside and corroded
some of the connections. This caused the line to hang itself up after
on incoming calls after the first ring.

Tightening all connections and cleaning out the corrosion fixed it.
I'll check the gasket when I have more time, and spray some Water
Displacement (40) around inside....

jak

 

[w_tom]

Grounding wire is typically gray or green. If green, then 10 AWG is
in Home Depot, Lowes, or any electrical supply company. But that
ground wire is their responsibility. You don't pay anything for them
to fix their ground wire. However verify or install an 8+' earthing
rod before they fix their wire. That 8 foot electrode (or network of
electrodes) should make a 'less than 10 foot' connection to NID as well
as to breaker box and cable TV. You provide a preferred earthing
electrode that already earths AC breaker box.

Sometimes a telco lineman can detect failures with a tester. Problem
that would not be apparent on your phone (during dry days) can
sometimes appear as leakage to earth on his tester. Business office
will recite reams of rules such as who pays that $99. But a lineman is
typically good about finding a problem even when noise does not exist
today. Good as long as he gets details from you and not from the
business office. Generally, a lineman will inspect your wire back to
the CO even if reason for noise is not apparent. Some problems can
only be located by inspection.

However some telcos are now instituting cost controls. If a lineman
gets the call too late in his day, he may simply declare the wire good
without inspecting. Executives give him hell for doing overtime to
complete a job. Therefore he may sign off on the job early. This
problem created when business school trained managers (who never worked
as linemen) know better.

Sounds like water is dripping into a splice somewhere back towards
the CO. All wires should enter a junction box by dropping down below,
then rising up from beneath. If not, then even a taped wire will
conduct water 'hum destructively' into a splice. Verify that every
wire into that NID comes up from below. Verify that no tapes over
wires are exposed to the weather.