Water Main Ground EMF

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Sammy555

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Ny
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Hi guys
A few people mentioned you guys might help.

I'm getting a terrible buzzing through all of my guitars - on a spectrum analyzer it's centered mainly around 2.5 khz - I've ruled out everything in the house I've turned off all Breakers but one and then I've tried multiple outlets in the house and I have this one spot, where I have to record, in the middle of my recording room where I'm getting this terrible buzzing, while in other rooms, except the joining room, I don't get it at all(I've moved my setup to various rooms & outlets and using a long guitar cable, the noise still happens in the recording room. If I point my guitar humbucker right down to the floor the buzz increases dramatically. Underneath me is the basement and I found a ground wire running on the basement joists that leads to the water main and it comes from the main breaker box, and even with the mains power off in the house, the ground wire's the only thing that's admitting any EMF so those magnetic readings coming from there with my guitar plugged in and only one Outlet on in the entire house, it still buzzes in that room. It buzzes really loud exactly where this line is & it goes across another room in the house I brought the guitar in there and it buzzes dramatically when I put it to the floor there too, so it seems like magnetic interference is coming through the floor. I shielded the inside of the guitar with copper foil but I'm told magnetic interference is different than electrical Etc? (don't know). I've tried so many things I'm not sure if this is exactly what is happening but is there any way to Shield that wire downstairs because I can't move it - or I should say I'm afraid to mess with it (I've rebuilt amplifiers and repaired circuit boards but I only have a layman understanding)

I just wanted to add. After reading a thousand websites I did find people that had this ENF actually through all their plumbing pipes making the entire house a buzz trap for their guitars. They fixed it with a dielectric union but mine is just, seemingly, the ground wire.

Thanks for taking the time read
 
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You need a professional to troubleshoot this. Don’t do anything yourself as it could be very dangerous.
It sounds like you have current flowing on the grounding electrode conductor (GEC) even with your main shut off. If so, you may be conducting one of your neighbor’s neutral current through the municipal water system and then your EGC. It could be a problem with either that neighbor or even the utility’s wiring.
 
This is not a DIY forum, and the moderators will shut this thread down if it veers in a DIY direction. General 'what is going on' and what should I tell an electrician questions are generally allowed.

What you describe strongly suggests current flowing on that 'ground wire'. You've been using your guitar to measure the magnetic field around that wire. Messing with this wire is specifically a job for an electrician for a major safety reason: while this wire is intact it is at very low voltage, but since current is flowing if you cut the wire one end of the cut might jump to a dangerous voltage.

Current flowing on metal water pipes has been known to shock plumbers when they cut the pipes. The current flow on the wire is certainly leading to current flow on a pipe somewhere.

Fixing this problem will probably require both an electrician and a plumber. The electrician needs to figure out the source of the current on the pipe/ground wire, and the plumber might need to change piping to avoid some otherwise required 'grounding'.

-Jonathan
 
Anytime there is a common metal underground water pipe that serves multiple buildings the neutral is required to be bonded to the water pipe at each building. This places the metal underground water pipe in parallel with the neutral and there will always be neutral current on this parallel path. It is not uncommon to have 25% or more of the neutral current on the water pipe system. With the current codes, the only way to eliminate this current flow at your building is to make changes in the underground water pipe that serves your building. You need to replace it with non-metallic piping, or insert some type of dielectric fitting in the underground water pipe to prevent this code required parallel path for neutral current.
 
winnie said:
This is not a DIY forum, and the moderators will shut this thread down if it veers in a DIY direction. General 'what is going on' and what should I tell an electrician questions are generally allowed.

What you describe strongly suggests current flowing on that 'ground wire'. You've been using your guitar to measure the magnetic field around that wire. Messing with this wire is specifically a job for an electrician for a major safety reason: while this wire is intact it is at very low voltage, but since current is flowing if you cut the wire one end of the cut might jump to a dangerous voltage.

Current flowing on metal water pipes has been known to shock plumbers when they cut the pipes. The current flow on the wire is certainly leading to current flow on a pipe somewhere.

Fixing this problem will probably require both an electrician and a plumber. The electrician needs to figure out the source of the current on the pipe/ground wire, and the plumber might need to change piping to avoid some otherwise required 'grounding'.

-Jonathan
Click to expand...
That only happens when the the service neutral is open or has a high resistance. The issue is that the neutral path via the common underground water piping system is often so good that no one knows that the service neutral has been compromised. With an open service neutral or a high resistance on the service neutral, when the plumber cuts the underground pipe the voltage across the ends of the pipe will be the line to neutral voltage of the system and be a serious shock hazard.

There is no easy way to know that this is an issue, so some plumbing contractors require their plumbers to install a jumper before cutting a metal underground water service pipe. You could use a clamp-on amp meter on the pipe, but even a number of amps of current on the water pipe does not mean there will be a shock hazard. Sometimes the resistance of the water pipe path is close to that of the service neutral and the two paths are a current divider.
 
Thanks guys
Amazing. I installed sprinkler systems when I was younger and I can't tell you how many times I cut right at that main water without ever realizing it could have voltage. I have also cut into pipes here to make repairs on the water heater & boiler away from the main.

As I heard it might not be safe to directly use my multimeter I didn't check with it but I did use a touchless voltage tester and EMF detector and only got magnetic readings on the emf. It's detectable on the pipes around the main water but seems to disappear the further along the plumbing pipes.

I'm was hoping there was a way to shield my recording room floor or the wire to divert it away. Thanks for the knowledge
 
An ordinary multimeter can be used to measure voltage or current. There is almost certainly very little voltage on those wires/pipes, and trying to measure this voltage is perfectly safe. However, to measure current you need that current to flow _through_ the multimeter, and that means breaking the circuit, and then sticking the multimeter into the circuit. This would be very much not safe in your situation!

Since it is the current that creates the magnetic field, you pretty much don't care about voltage, ergo a multimeter is a bad tool for your situation.

A different tool, sometimes combined with a multimeter, is a 'clamp on current meter'. This is just a sort of spring clamp that you put _around_ a wire. It measures the current flowing in the wire by measuring the magnetic field around the wire. Using one of these on your ground wire (or plumbing pipes if the jars are big enough) would be perfectly safe.

A sufficiently good conductor (read a superconducting material) will shield magnetic fields. Unfortunately this is not a practical solution for shielding your recording room.

You could certainly have an electrician replace the ground wire with one routed in a better path, something that avoids your recording area. But IMHO the best approach is to have the electrician try to figure out what the source of this undesired current flow is.

As @don_resqcapt19 states, this current could be from _normal_ operation. But given that you see this current even with most circuit breakers off, I suspect something is broken somewhere, possibly in a neighbor's house as @retirede suggests.
 
winnie said:
An ordinary multimeter can be used to measure voltage or current. There is almost certainly very little voltage on those wires/pipes, and trying to measure this voltage is perfectly safe. However, to measure current you need that current to flow _through_ the multimeter, and that means breaking the circuit, and then sticking the multimeter into the circuit. This would be very much not safe in your situation!

Since it is the current that creates the magnetic field, you pretty much don't care about voltage, ergo a multimeter is a bad tool for your situation.

A different tool, sometimes combined with a multimeter, is a 'clamp on current meter'. This is just a sort of spring clamp that you put _around_ a wire. It measures the current flowing in the wire by measuring the magnetic field around the wire. Using one of these on your ground wire (or plumbing pipes if the jars are big enough) would be perfectly safe.

A sufficiently good conductor (read a superconducting material) will shield magnetic fields. Unfortunately this is not a practical solution for shielding your recording room.

You could certainly have an electrician replace the ground wire with one routed in a better path, something that avoids your recording area. But IMHO the best approach is to have the electrician try to figure out what the source of this undesired current flow is.

As @don_resqcapt19 states, this current could be from _normal_ operation. But given that you see this current even with most circuit breakers off, I suspect something is broken somewhere, possibly in a neighbor's house as @retirede suggests.
Click to expand...
Even with the main off in your building, your service neutral and the GEC to your water pipe is still parallel path for all of the other service neutrals in the area that are connected to the same common underground metal water pipe system. The current will flow on all of the available paths. If it is more than an amp or two with your breakers off, then there could be an issue with a service neutral in anther building.
 
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