bad ground = phone hum?

In article , herb snipped-for-privacy@mail.com (known to some as herb snipped-for-privacy@mail.com) scribed...

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.

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! 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.

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).

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.

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.

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 earth> There is a heavy wire running from the outside phone box (company side)

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

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 dripp> Thanks to all who replied. I did do as you say, on the first day. The