Hi guys, I didn't see anything on this problem already. I just bought a new clothes dryer and when it is running it causes loud hum in my subwoofer amp and my mains amp. This only happens when it is running. I'm not sure what direction to take to resolve this since it isn't a component causing the hum.

Does anyone have an idea? I just spent a fortune on the new washer and dryer, my wife does laundry every evening while we watch movies. Not good!

Any advice? I have a Monster power strip that is supposed to condition as well. I spent like $250 on it, not sure what model but I can get more info. I'm willing to spend $$ on gadgets to eliminated this problem.

Darren

Update, shortly after posting this I disconnected my HD satellite ground at the splitter. Hum from the dryer is now gone.

Any idea's where the loop could be from? It was grounded properly to the house ground that connects to the gas pipe and eventually terminates at the ground rod the house panel connects to.

First up remove the washer and dryer from your home theater room. Or, leave them in and the noise of the machines will mask the hum.

:rolleyes:

Try looking in this thread:

http://www.avsforum.com/avs-vb/showthread.php?t=322698

It was grounded properly to the house ground that connects to the gas pipe...

You have to be kidding!

BOOM!!!

Get that resolved ASAP. That by no means is a "proper" ground.

Update, shortly after posting this I disconnected my HD satellite ground at the splitter. Hum from the dryer is now gone.

Any idea's where the loop could be from? It was grounded properly to the house ground that connects to the gas pipe and eventually terminates at the ground rod the house panel connects to.

The cable guy who seems to be a fixture in the area told me two of the major reasons for rolling a truck are poor signal or hum due to bad connections. Bad f connectors or bad connections from the grounding block to the clamp on the grounding rod, water/gas pipe. He routinely backs off and then retightens every cable connection (that he can see) from the grounding block to the last device as well as each of the grounding connections from the cable grounding block to the final grounding clamp on the gas pipe or grounding pipe.

Bad f connections can be due to age, but the most likely cause is owner error—using screw on connectors or installing crimp or compression connectors improperly.

One of the other techs out here usually just installs a new wire from the cable ground block to the grounding point and doesn’t bother to check the old connections. If you haven't already done so you might want to check those connections in your system.

You have to be kidding!

BOOM!!!

Get that resolved ASAP. That by no means is a "proper" ground.

Actually no, there is no boom. It is very common in WA to ground non-powered items in this fashion. IE: water heater, cable, water pipes...

Try looking in this thread:

http://www.avsforum.com/avs-vb/showthread.php?t=322698

Yup, been reading that but didn't seem to pertain to my problem but now that I isolated it to the cable grounding block it is starting to apply.

Actually no, there is no boom. It is very common in WA to ground non-powered items in this fashion. IE: water heater, cable, water pipes...
Cold water pipe... perhaps in older installs.

http://www.inspect-ny.com/electric/Electrical_Ground_Inspection.htm

Yup, been reading that but didn't seem to pertain to my problem but now that I isolated it to the cable grounding block it is starting to apply.

I wouldn't have expected it to discuss hum/grounding problems caused by a clothes dryer, but the thread IS about hum problems and how to cure them .... ;)

Water pipes yes, gas pipes NEVER.

Update, shortly after posting this I disconnected my HD satellite ground at the splitter. Hum from the dryer is now gone.

Any idea's where the loop could be from? It was grounded properly to the house ground that connects to the gas pipe and eventually terminates at the ground rod the house panel connects to.

Actually no, there is no boom. It is very common in WA to ground non-powered items in this fashion. IE: water heater, cable, water pipes...That's probably perfectly acceptable from a safety stand point, but not so great from an electrical stand point, at least where the power needs of an audio/video system are concerned.

There's a good chance you can fix this problem by bypassing the water pipe system and sending the satellite ground directly to the ground rod. Many, if not most ground loops end up being cause by dumb stuff like corrosion build up at the termination point, a loose screw, etc. things that add resistance and prevent a good, secure ground connection between the item being grounded and the rod.

Bypassing the water pipe system just seems like a good idea to me. Who knows how many corroded junctions there are, meandering all through the house, between the point where the sat splitter grounds to the pipe and the ground rod outside the house? Any or all of them can be, and probably are, adding resistance to the sat ground, while the electrical circuits are directly grounded to the rod with no corrosion-resistance factor. That difference in potential between the two is probably what is causing the ground loop.

Regards,
Wayne A. Pflughaupt

...and newer homes/developments use plastic water service lines to the home. For older homes, water service lines (outside the home) may have been "upgraded" to plastic which can no longer provide a ground.

One cannot assume that copper cold water pipes inside the home means your service feed is copper.

Water pipes yes, gas pipes NEVER.

Sorry, but the doubters are wrong. Every home I've owned or remodeled has been this way. The new shop I'm building will be this way by code. It is perfectly acceptable and harmless... You HAVE to ground gas pipes and by nature, they are already grounded since they are burried before they come into the house. Grounding the water heater and cable etc... to the gas pipe changes nothing.

I'm guessing the two sources of ground are the gas pipe vs the electrical and I should run the cable ground wire to the electrical ground as mentioned above.

That's probably perfectly acceptable from a safety stand point, but not so great from an electrical stand point, at least where the power needs of an audio/video system are concerned.

There's a good chance you can fix this problem by bypassing the water pipe system and sending the satellite ground directly to the ground rod. Many, if not most ground loops end up being cause by dumb stuff like corrosion build up at the termination point, a loose screw, etc. things that add resistance and prevent a good, secure ground connection between the item being grounded and the rod.

Bypassing the water pipe system just seems like a good idea to me. Who knows how many corroded junctions there are, meandering all through the house, between the point where the sat splitter grounds to the pipe and the ground rod outside the house? Any or all of them can be, and probably are, adding resistance to the sat ground, while the electrical circuits are directly grounded to the rod with no corrosion-resistance factor. That difference in potential between the two is probably what is causing the ground loop.

Regards,
Wayne A. Pflughaupt


I think you are definitely on to something with this. I'm gonna try running a new ground wire from the satellite splitter to the electrical ground on the side of the house.

I guess you didn't read the link provided about bonding multiple ground points.

Grounding to "pipes" willy-nilly (just because they are underground) and a single earth ground is not the same.

You can ground any pipe you like... it shouldn't be considered an earth ground.

Good luck with your ground loop. ;)

We have lots of issues here:

a) Gas pipes! Black pipe and a four letter acronym for a corrugated SS pipe that I don't remember. Black pipe may be grounded but should never be used as a conductor for the electrical ground system. The SS pipe has recent safety issues with new rules.

b)Clothes dryers. Electric clothes dryers often get wired wrong, especially when wired by the delivery people.

I guess you didn't read the link provided about bonding multiple ground points.

Grounding to "pipes" willy-nilly (just because they are underground) and a single earth ground is not the same.

You can ground any pipe you like... it shouldn't be considered an earth ground.

Good luck with your ground loop. ;)

I did read that and you can tell by my response. I identified the gas pipe as the second ground.

We have lots of issues here:

a) Gas pipes! Black pipe and a four letter acronym for a corrugated SS pipe that I don't remember. Black pipe may be grounded but should never be used as a conductor for the electrical ground system. The SS pipe has recent safety issues with new rules.

b)Clothes dryers. Electric clothes dryers often get wired wrong, especially when wired by the delivery people.

It isn't being used for the electrical ground system. I double checked the dryer wiring and it is good. I'm pretty sure it was the double ground of the gas pipe and the satellite. It has nothing to do with the dryer, it just brought the problem to light. They should have grounded the satellite splitter to the electrical ground and not the gas ground to avoid the double ground issue.

OT:
The gas pipe with possible safety issues is "CSST"

Any time you use piping of any kind connected to any type of electrical device it IS a grounding conductor that MAY carry current in a fault mode. As most gas feeds to homes are now plastic from the street, there is no earth connection of the gas line in the house, therefore is does not provide any safe or reliable means of grounding. It is not now and never was permitted to use a gas pipe as a service ground to the load center. Water supply lines are now frequently in the same boat as most new service is PEX or PVC and not conductive.

Ground connections in the load center and NOT part of the ground /neutral loop. These grounds are primarily for spurious induced voltages on the neutral buss.

The whole house protection system is the best way to start controlling surges, but the hum the OP was speaking of is most likely a harmonic on the phase side, not the ground side.

The very best but albeit not the simplest method to totally isolate everything is to use an isolation transformer to power the entire system. These are not cheap or light, but they DO isolate noise inducing motors etc from the sound system supply.

These noise issues can also frequently be solved by installing clamp-on ferrite "filters" on the power cables.