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Ground Loop with 2 ground rods

6K views 44 replies 12 participants last post by  spkr 
#1 ·
Hi


I recently had an electrician install circuit breakers that replaced fuse based breaker. I now have a ground loop in my audio gear and speakers. What he did was install a new ground rod. He also has a copper wire running to my water pipe. So 2 copper wires running to circuit breaker.


My question is, does having 2 grounds, like he setup (an earth ground rod and ground wire to water pipe in essense 2 grounding spots), cause ground loops? Is this my problem?


thanks
 
#2 ·
Rewiring the box probably changed the ground system as well. It may have nothing to do with the two grounding points from the box.

Do you have a cable or satellite box? If so, I would unhook the cable from it to the wall and see if that breaks the loop. That would be my first suspect. If so, an RF isolator is a pretty cheap fix.

If you have gear plugged into different outlets, it is possible they are now on different breakers and/or have different ground paths.

You might also see if the electrician will help. Some may know more than others about things like ground loops...
 
#3 ·
Rewiring the box probably changed the ground system as well. It may have nothing to do with the two grounding points from the box.

Do you have a cable or satellite box? If so, I would unhook the cable from it to the wall and see if that breaks the loop. That would be my first suspect. If so, an RF isolator is a pretty cheap fix.

If you have gear plugged into different outlets, it is possible they are now on different breakers and/or have different ground paths.

You might also see if the electrician will help. Some may know more than others about things like ground loops...
Thanks DonH50


I do not have a cable box hooked up to the speakers and still have the hum. Even radio boxes I have in other rooms have this hum.
 
#4 ·
My question is, does having 2 grounds, like he setup (an earth ground rod and ground wire to water pipe in essense 2 grounding spots), cause ground loops?
It can. There's no reason why the service entrance should be grounded in two places. It was common in the days of fuse boxes to use the water supply pipe coming into the house as the grounding point for the box, because the pipe was there. That practice was ended when code mandated that a ground rod be used. He should have just used the rod. I can't think of why he left the ground attached to the pipe too, but electricians aren't typically schooled in the ins and outs of ground loops.
Get an outlet tester to test all of your outlets, disconnect the wire to the pipe, test the outlets to be sure they're OK. Hopefully that will cure the problem.
 
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#5 ·
I am not sure why radio boxes in other rooms not connected to the main system would hum. I wonder if one or the other of the grounds was improperly wired, or if the box was properly installed.

Like Bill said, you should not need two grounds. The electrician may have felt one would back up the other. If both grounds go to the service box, that should still be one ground to the rest of the outlets, unless there is another ground someplace. Something seems a little strange... Do you have ore than one service (fuse/breaker) box?

Can you list the components of your system? Is everything plugged into the same outlet?

You can buy a cheap outlet tester from Wal-Mart, Home Depot, etc. that will show a light if the outlet is not wired properly.
 
#6 · (Edited)
I am not sure why radio boxes in other rooms not connected to the main system would hum. I wonder if one or the other of the grounds was improperly wired, or if the box was properly installed.

Like Bill said, you should not need two grounds. The electrician may have felt one would back up the other. If both grounds go to the service box, that should still be one ground to the rest of the outlets, unless there is another ground someplace. Something seems a little strange... Do you have ore than one service (fuse/breaker) box?

Can you list the components of your system? Is everything plugged into the same outlet?

You can buy a cheap outlet tester from Wal-Mart, Home Depot, etc. that will show a light if the outlet is not wired properly.
Hi Don


The components of my system are Oppo 105d, going to Marantz 8801, to ATI 6005 signature series amp. All hooked up via XLR. I use 2 outlets for these components; amp in one the pre pro and Oppo in the other. Checked outlets all checked out. That's why I thought it had to be the 2 grounds. Ill check this and report back. have no florescent lights and no light dimmers etc. And I only have 1 circuit breaker. I took components to friends house, hum goes away.


I just checked and there are 3 copper ground wires connecting to circuit breaker. I think he said there was a ground rod in, but he was going to install another one just in case now that I think about it, plus the ground going to water pipe. (one copper wire hooked up to circuit breaker, the others clamped onto that copper wire)
 
#8 ·
Do you hear a hum in a portable radio, not plugged in to any power or connected to anything else?
There could be a bad connection on any one of the grounds, and any ground current might be causing a "buzzing" kind of arcing noise.
 
#9 ·
My home has two grounds, the old water pipe way and two ground rods six feet apart. Luckily, I have no hum problems.
 
#10 ·
Multiple ground rods are supposed to be bonded. If you have a ground rod (properly installed), there's no need to use a cold water pipe.

IMHO, contact the electrician to assist and resolve the issues that didn't exist before the work the done.

Just curious... was a "permit" obtained to perform this work?
 
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#11 ·
Multiple ground rods are supposed to be bonded. If you have a ground rod (properly installed), there's no need to use a cold water pipe.

Now that you jogged my memory, my ground rods are bonded. I used these things that we used to bond wire to railroad tracks. Damn if I can remember what they're called. You put these little cups of powder on top of the rod and wire and light them on fire. Permenant weld.
 
#14 ·
Agreed. My grandparents wanted me to rewire their old house. I looked at some of the wires, tube and knob plus ratty old cables with the insulation falling apart, and it was just scary. I graduated instead and moved out. I suspect that was always their real plan... :) They moved out a few years later and the buyer gutted much of the place and rewired it in the process, also replacing the old furnace and (steam radiator) heating system.
 
#16 ·
also replacing the old furnace and (steam radiator) heating system.
My house had an oil fired furnace that was originally coal fired. It sat in the basement under the living room, with a grate in the floor. Pure convection, no fans, no ducts, no radiators. And no heat in the basement, it all rose straight up into the living room. I managed with it for the first winter, by the second winter it was long gone.
 
#15 ·
The licensed electrical contractor that performed the work and the electrical inspector should be able to work out the OP's issues according to the local electrical codes. Assuming they applied for the proper permit. :)
 
#20 ·
The electrical code is for safety, not performance. Ditto for permits. Audio hum falls in the category of performance. If there were other failures in the house then that would matter.

Here is the description of NEC: http://en.wikipedia.org/wiki/National_Electrical_Code

"The National Electrical Code (NEC), or NFPA 70, is a regionally adoptable standard for the safe installation of electrical wiring and equipment in the United States. It is part of the National Fire Codes series published by the National Fire Protection Association (NFPA), a private trade association.[1] Despite the use of the term "national", it is not a federal law. It is typically adopted by states and municipalities in an effort to standardize their enforcement of safe electrical practices.[2] "

Since OP has already tested the outlet and the connections are right, permitting, etc. is not going to be a productive path.

He is also using balanced connections which should do away with ground loop issues.
 
#17 ·
AFAIK they went straight from coal to gas (no oil). Still had a coal bin in the basement and coal shoot to dump a load from the outside. Great fun to play around when I was a kid, except for the blackened clothes, and of course the old boiler and all the pipes that hissed, moaned and snapped was very scary to young kids. For "older kids", leaky pipes were no fun, nor the corroded relief valve that decided to snap off and go through the ceiling.

On-topic: What Ratman said, except my experience with electricians and ground loop issues has been mixed. Not all of them understand the issue and thus things could become frustrating for all.

If there is no satellite/cable connection to the system (per the OP) and all components are plugged into the same outlet, now and before the ground rod was added (not sure that was answered?), still hard to see where a loop is being formed. The hum from other radios is also perplexing if they are completely independent. That is what I find concerning; maybe a ground was not properly wired or a more fundamental problem exists. Like improperly wired outlets. Either way the advice to recall the electrician to take a look would be my first step.
 
#18 · (Edited)
On-topic: What Ratman said, except my experience with electricians and ground loop issues has been mixed. Not all of them understand the issue and thus things could become frustrating for all..
Experienced is not always best (experience is what you think you know... until there's a problem). Licenced helps. Also, obtaing a permit to perform the work is good for both the contractor and the client.

The problem didn't exist prior to the work performed.
So, who's at fault? The client, the contractor or the inspector?

IMHO... a reputable electrician would be willing to resolve the issue.
 
#26 ·
I had a little chuckle about this comment, but I did see it happen. (The Shock)
 
#24 ·
Mine too, but contractors buried the main house rods when we added a shed and they trenched for the power feeds; the rods got covered when they back-filled the trench. It happens.

The cuter one I have seen is when the service ground was run in the walls to a ground rod in the basement, also in the walls... Pretty sure that one is against code!
 
#31 ·
I don't really understand your point, but... if all my gear worked/sounded just dandy PRIOR to the "electricians" work, I'd ask the "electrician" before I'd buy new stuff. ;)
 
#33 ·
Here is the best thing you can do to troubleshoot this problem: call Jensen Transformers: http://www.jensen-transformers.com/contact/

This is what they do day in and day out. And no one I have seen has a better grasp of equipment hum than Bill Whitlock. Yes, they might try to sell you a transformer but what they build is first class and will be a cheap solution. Bill understands both equipment side and equipment issues so if he by chance responds do you, you will be in excellent hands. Create a block diagram and connectivity of your gear before you contact them as that is the first thing they will ask for.

They also sell/give away at conferences this little RCA termination that you can use with a clever process to pinpoint the exact piece of audio gear that is causing the hum.

The proper way to analyze the problem requires a couple of instruments that unfortunately sets you back $500+ (sensitive AC current leakage meter and high-end outlet tester that measures the voltages under full load). I have these and they are quite eye opening the first time you use them. And the above mentioned input terminator. Without them, your best bet is to get expert advice per above and take advantage of their wisdom and countless experience.
 
#34 ·
Here is the best thing you can do to troubleshoot this problem: .
IMHO, The best thing to diagnose the issue (problem) is to contact the "electrician" before going to extra effort and/or expense.

Throwing money at a "problem" is not always the right answer. But I will admit... you are a persistent young fella. :)

Today: No problem
Tomorrow: "electrician" creates problem

Makes one question. ;)
 
#38 · (Edited)
I can agree that there may have been (or still is) a "grounding problem". Nonetheless... why is it so much of a probelm to call the electrical contractor to evaluate the situation?

Also... why would a competent/licenced electrical contractor install 3 grounds? Are they bonded?
Also... no one asked about the wiring the home. Is it all copper romex? Is there aluminum wiring? Is there knob and tube...,..... etc.

Anyone can mask a problem with gadgets, but let's get to the potential issues that may need to be addressed.

Everyone has stated over the years that using a 3 prong to 2 prong adapter is not recommended, but... no one questions the competency of the "electrician" that replaced a "fuse panel" with a "breaker panel" and may not have properly grounded the new work?:eek:

Today: MY house exists
tomorrow: MY house has burned down

EDIT:
Unless I missed a post, the OP never stated whether the "electrician" was licenced nor whether permits obtained. Anyone can buy the materials to change out a fuse box and replace with a breaker box and drive a rod into the earth. That doesn't necessarily denote that the work has been performed properly and according to code.
 
#39 ·
I can agree that there may have been (or still is) a "grounding problem". Nonetheless... why is it so much of a probelm to call the electrical contractor to evaluate the situation?
For the same reason that when you call tech support for anything related to your computer or Internet, they ask you to reboot your machine. It is busy work unrelated to the nature and cause of the problem.

I have tried to explain this to you but you seem unwilling to listen. So I will be more specific but holding little hope that it will make any headway.

The word "ground" in ground loop has nothing, let me repeat, nothing to do with the ground coming into your building. It refers to ground pin of the input on your audio equipment. It is that ground, which if at a different level than the source equipment, will cause the hum or "ground loop."

The ground in your breaker panel is there to shunt external surges (like the infamous "lighting") to the ground. It is also there as the third leg in your outlet as to eliminate the safety risk of your metal encased equipment becoming energized, causing a potentially lethal shock. Its purpose is not to reduce noise, get rid of hum, etc. no matter how much you want it to be associated with that. OP's house has the right ground connection for its intended purpose. Safety.

There is a complex connection between your electrical system and how consumer audio gear works that can cause hum to all of a sudden appear. Or disappear. Without instrumentation you will not know why is there.

Also... why would a competent/licenced electrical contractor install 3 grounds? Are they bonded?
He can put a thousand grounds there. It has nothing to do with the topic at hand. Go and hang out in electrician and building inspector forums and ponder about it there. As I explained, there is only one ground in the building which is the requirement for safety.

Also... no one asked about the wiring the home. Is it all copper romex? Is there aluminum wiring? Is there knob and tube...,..... etc.
You can have systems with no hum using any kind of wiring. If you think otherwise, you need to explain.

Anyone can mask a problem with gadgets, but let's get to the potential issues that may need to be addressed.
No. Putting a transformer does not "mask" the problem. It removes it. It isolates the ground connection between two pieces of gear as it should have been day one in consumer audio. Equipment should tolerate differing ground potentials but depending on the design, it may not do so or do a borderline job. Since you can't change the design of your equipment or keep rewiring the building hoping you get lucky, the transformer provides an appropriate solution. If you don't like that option, sell the gear and buy something else that works better.

Everyone has stated over the years that using a 3 prong to 2 prong adapter is not recommended, but... no one questions the competency of the "electrician" that replaced a "fuse panel" with a "breaker panel" and may not have properly grounded the new work?:eek:
Once again, OP used an outlet tester and showed correct wiring. Nothing else in his home is having a problem. You can imagine all that you want about this situation but that is not how we assess and solve problems like this.

Today: MY house exists
tomorrow: MY house has burned down
If having audio hum causes safety issues that cause fire, it would be in the code.

You are barking up the wrong tree Rat. Countless people have proper and safe wiring, buy a new piece of equipment, get cable, dish service, etc. and get hum. Then move wires around, or some other random thing and hum gets less loud, louder, or goes away. All again, in a home that is wired safely.

EDIT:
Unless I missed a post, the OP never stated whether the "electrician" was licenced nor whether permits obtained. Anyone can buy the materials to change out a fuse box and replace with a breaker box and drive a rod into the earth. That doesn't necessarily denote that the work has been performed properly and according to code.
Yup. And a drunk sailor may have made the circuit breakers in your home so let's worry about it catching on fire too....
 
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