Hi and thanks. The way that was written made it sound like I turned the main off to protect myself. That was not the case. I wanted it off to make sure the hum wasn't coming because of a current draw from the house. At that time, I was no aware that the hum was not evident from outside. Maybe because of area noise. Anyway, I was surprised when I did grab the neutral and the mains, separately, and they were vibrating they way they were. Not a casual vibration. I called PECO and they said it was arcing, which it is not. All 3 connections are tight and secure, tape still in excellent condition, and no signs of heat. They said, if it was not arcing, then it was my problem.

PS: I did remove the 60 amp and install the 200 amp service myself those years ago. Changed the meter box and made the temporary connections until PECO inspected and resealed the meter.

This doesn't sound like an electrical problem to me. Is your service drop taut? Have you tried adding some slack?

I was able to move it enough to slip a piece of rubber hose between the strap holding the cables and the hook screwed into the house frame. Didn't help but it's not so tight that it can't be moved. Thanks

PECO came out and installed a plastic hook to screw into the house to hold the cable. They also lengthened the cable a bit. 99% of the vibration and hum is now gone. It was shaking so much both men said they had never seen it before and mentioned the transformer is most likely the cause.

Thanks for the update. Never heard of a plastic service hook. I meant to ask if there was a transformer on your pole. Strange that it could cause enough vibration to travel down the drop to your house - you would think you would have been able to hear it standing in the street under it.

Sounds like a temporary fix what will happen to that plastic hook if ice buildup or a tree falls onto the utility wires? Quite obvious it will rip that plastic hook right out of wherever they screwed it into the house. I would recommend a whole house surge protector installed in the main breaker panel to protect electronics and appliances and a rigid riser pipe connection to the utility grid wires.

Useful information would include frequency of the vibration. Using an E-M meter to measure field intensity. And examining for harmonics on AC power. Latter could indicate a future failure that is best averted today.

Apparently wires are vibrating due to an EM field. That field typically would not vibrate aluminum or copper wires. A very strong magnet (ie found inside disk drives - most other magnets are not strong enough) could identify a potentially magnetically vibrated material. Apparently wire is resonant with frequency of that EM field. Plastic hook would change that frequency (not solve a problem) just like fingers on a guitar.

As for the hook, they referred to it as a plastic hook but also mentioned that it had metal threads for securing it to the house. I did not get to see it but overall, I believe it was a combination of both the plastic style hook replacing the all metal hook, and the increased slacking of the wires. They did say the wires looked tight and could of been the result of work done on a neighbors home making mine a little tighter. My bottom line is that since they have done it, the vibration is still there but I can no longer heart it or feel it without the use of a cup to the wall. A good point to make here is that when the unhooked the ground wire securing strap, from the hook that was hooked to the house, the noise was completely gone. Not even a cup to the wall heard it. At one point they talked about using a weatherproof 3/8" nylon cord as a method of securing the ground to the house instead of the metal loop strap.

Glad you cant hear it anymore. I think after a week of not thinking about it you wont notice it. I have a radon fan in my attic I did significant tweaks to get rid of noise and can only hear it directly underneath it if I try to hear it. When you are listening for it you hear it more.

G thom you may be on to something there. When dealing with soundproofing in general, managing the frequencies within the heard level is key. If you change the frequency to something not heard easily then that could do the trick.

Check principle 2 here.

Again, no magnetic material should be in any of those cables. Using the magnet was important. To locate any wire that contains magnetically attractive material - that should not be there.