[Cheeseboy]

Over Christmas my electrician installed two dedicated AC lines to be used for my Audio System and Video System.   There was no room in the current breaker box and so an auxillary box was installed.  It appears to be a grounding problem.  It is intermittent.  Three minutes on and 30 seconds or so off.  On the Audio AC line one just needs to turn on the amp and get a loud humming noise from the speakers.  On the other line, the Video line one gets the same humming from the audio speakers in the TV and the ocasional purple strip across the top of the TV screen. 

The house I bought is wired differently upstairs than downstairs yet they share the same box.  Downstairs is 3 wire romex and the upstairs is the old two wire type of set up. 

The electrician is coming back Tuesday night to look and repair.  What should he be looking for in this application?

I can't tell you how concerend I am about this problem.  I just finally got this system sounding very good and now this set back. 

Help!

Steve

[jneutron]

It is intermittent.  Three minutes on and 30 seconds or so off. 
Steve

I'm just dying to know what in your house is on 3 minutes then off 30 seconds.

You have a sump pump perhaps?

jn

[dBe]

Some of your problem is more than likely due to the mixing of the 2 wire and 3 wire formats.  More than likely you have items in the 2-wire side of things upstairs where ther is a mixing of hot and neutral sides plugged into devices that want to see the common side observed...  too easy to do with nonpolarized plugs.  Try unplugging some TV's, electric blankets, etc. upstairs and see if you can find the culprit(s).

Like Mr. Neutron said - what cycles on and off at your house?

Also, check the cold water bond of the ground and see if there is oxidation there.

I hate hums........................

Dave

[jneutron]

  There was no room in the current breaker box and so an auxillary box was installed.

The electrician is coming back Tuesday night to look and repair.  What should he be looking for in this application?

I assume both circuits originate at the aux box.  If not, that may be better.

Within the box where both circuits originate, ask him if it is legit to wrap both grounds up to the buss, so that there is no loop between the bare copper wires.  Some other device's hot conductor may be coupling to the ground.

Ask him if the bond between ground and neutral is open in the box.  Only in the main panel should they be common, in the aux box neutral and ground should be independent. (code is diff in places, so ask nicely..)  the bonding conductor is not supposed to carry current normally, and if they are connected both at the main and at the aux, then neutral and ground will share the neutral current.

If you've connected this to an incoming cable, have him check the bonding of the cable at the entrance to the house.  If that is not done properly, then the cable wire could be bringing that hum in from one of your neighbors.

Maybe they have a sump pump??

That's all I got....I'm tapped.

Wait...do you or one of your neighbors have domestic water fed from a well? 

jn

[Cheeseboy]

I'm just dying to know what in your house is on 3 minutes then off 30 seconds.

You have a sump pump perhaps?

jn

It is not exactly on time just an aproximation of time.  We are on city water. 

[Cheeseboy]

Some of your problem is more than likely due to the mixing of the 2 wire and 3 wire formats.  More than likely you have items in the 2-wire side of things upstairs where ther is a mixing of hot and neutral sides plugged into devices that want to see the common side observed...  too easy to do with nonpolarized plugs.  Try unplugging some TV's, electric blankets, etc. upstairs and see if you can find the culprit(s).

Like Mr. Neutron said - what cycles on and off at your house?

Also, check the cold water bond of the ground and see if there is oxidation there.

I hate hums........................

Dave

We are hum haters!  Yayaa.  I have gone through the house looking for those culprits.  Electric blankets, small heaters and other such products.  I unplugged them and then powered up to see if they were causing this.  I just installed one of your Uber Buss with a Mongo AC cable on the Audio side of Things.  In your owners manual you mention GFI circuits.  There are many downstairs and a few upstairs in the house.  Nun are on these circuits that are new.  Is there a posibility these are a problem from somewhere else in the house.  Love the Uber by the way.  Antimode/Uber combo took my system to the moon.  Now this.

Steve

[srb]

We are on city water.

The sump pump they're referring to has nothing to do with your water supply, but is a float switch actuated pump in the lowest part of a basement where water that leaks in may collect and be pumped into a drain or elsewhere.

Steve

[Cheeseboy]

Thanks srb.  J asked about a neighbor with a well.  That was my response.   We do not have a sump pump on the property.   Septic Tanks don't have a pump do they?

[dBe]

We are hum haters!  Yayaa.  I have gone through the house looking for those culprits.  Electric blankets, small heaters and other such products.  I unplugged them and then powered up to see if they were causing this.  I just installed one of your Uber Buss with a Mongo AC cable on the Audio side of Things.  In your owners manual you mention GFI circuits.  There are many downstairs and a few upstairs in the house.  Nun are on these circuits that are new.  Is there a posibility these are a problem from somewhere else in the house.  Love the Uber by the way.  Antimode/Uber combo took my system to the moon.  Now this.

Steve

Well, I always look on the simple side of things when hunting down hums.  Too bad that didn't fix it.  Thanks for the comments on the Uber and Mongo.  I like it when people are happy.

I think Mr. Neutron has covered most of what is left... he was very thorough.

One other thing to look at would be the video side of the equation.  Cable installers are notorious for sloppy grounds and the hums they create.  Try unhooking the cable or satellite RG6 connection and see if that helps at all.

HUMMMMMMMMMMMMMMsssssssss suck.

Dave

[Cheeseboy]

The cable comes in on the same wall.  It is a brand new installation.  Should I disconnect on the outside or just in the inside will do?  My cable box has always hummed.

[dBe]

The cable comes in on the same wall.  It is a brand new installation.  Should I disconnect on the outside or just in the inside will do?  My cable box has always hummed.

Just there at your indoor receiver.  All you want to do is lift the cable ground from the system.

Dave

[golfugh]

Try running everything off of one line.  Solved my hum problem.  I also have 2 dedicated lines but can only use 1.

Mark

[DaveC113]

/\ Yes

[mcgsxr]

I know a lot of folks run their system off 1 dedicated line, and perhaps that does make it easier.

I currently have 8 of them to a pony panel in my media closet.  4 of them are used for audio, the other 4 for video and future fun (PJ and potential for powered screen).

I was careful with the phase of the ones I use for audio, and use the others for the video and future use.

It should certainly be possible to run 2 dedicated lines with no hum.

What does your sparky think it could be?

[Cheeseboy]

Mark,

Mr. Sparky (Love that) thinks it is a grounding problem and just has to look and find things.  I'm cutting and pasting suggestions to him in emails as they come up here. 

[Folsom]

Is everything connected to your system on the new service panel?

It seems the most common thing is when is when safety and circuit ground are looping all the way to the panel. Try touching the amplifier with a hand, and then other devices, see if the hum changes. That'll confirm that issue.

[Cheeseboy]

I'll try that tonight when I get home.

If I can start to make music that way then We're onto something. 

[MarkM]

Did the electrician run two separate lines or run a three wire and share the neutral?  I have had to deal with this issue a few times over the years.  Cured it at times with putting the dedicated circuits on the same leg in the panel, other times equipment wanted to be on opposite legs when dealing with multiple dedicated circuits.  Conductor routing?

Cable and satellite installs, poor bonding and grounding electrode conductors at the service equipment, inductive loads and dimmers all have the potential to wreak havoc for us wanting to enjoy our hobby in silence.  It is best if cable, satellite and telephone (intersystem bonding termination) are all bonded at the same point.

You could also shut circuits off one by one to see if it clears.  Good luck.

[pansixt]

Many people use amplifiers (signal boosters) for their Cable or SAT service. This amp has it's own power pack (usually a wall wart converting it to DC Volts) plugged into an AC receptacle somewhere in the home with a coax cable back to the SAT or Cable splitter.

When these power packs are bad, I have heard an audible hum from the TV and seen Hum Bars on the screen.
If you have one of these, unplug it temporarily. Of course when you do,your TV pictures will be bad and your Internet may go down,
but if it solves the hum then you need your service provider back there and not Sparky.

Cable, SAT and Phone should all be co-bonded to the homes power ground like Mark stated. If this ground connection is loose or non-existent, it could cause the same issues.

Can't wait to hear the solution.

James

[DaveC113]

I know a lot of folks run their system off 1 dedicated line, and perhaps that does make it easier.

I currently have 8 of them to a pony panel in my media closet.  4 of them are used for audio, the other 4 for video and future fun (PJ and potential for powered screen).

I was careful with the phase of the ones I use for audio, and use the others for the video and future use.

It should certainly be possible to run 2 dedicated lines with no hum.

What does your sparky think it could be?

True, if the subpanel is close to the system then there isn't likely to be an issue.