Grounding/Bonding with respect to ElectroMagnetic Field issues....

[jango]

Are there any special scenarios that are acceptable with respect to the standard electrical service grounding (continuous conductor from service to ufer (ground rod to water service pipe entrance) and bonding (hot-cold-gas) that would make any differences regarding the concerns that people have about the EMF effects. Also, are there any recommended websites regarding the whole issue of EMF and residential electrical wiring method recommendations to minimize the potential effects of EMF?

 

[SG-1]

Go to Mike Holts Home Page > Go to the left side and click on Technical > Click on Electromagnetic Fields under Subject Topics.

NEC compliant grounding will not produce electromagnetic fields unless fault current is flowing or the wiring installation is faulty, like a regrounded neutral.

 

[gndrod]

Are there any special scenarios that are acceptable with respect to the standard electrical service grounding (continuous conductor from service to ufer (ground rod to water service pipe entrance) and bonding (hot-cold-gas) that would make any differences regarding the concerns that people have about the EMF effects. Also, are there any recommended websites regarding the whole issue of EMF and residential electrical wiring method recommendations to minimize the potential effects of EMF?

Karl Riley's book TRACING EMF'S has examples and illustrations concerning induced energy fields that show where adjustments from analysis can eliminate detrimental conditions found in electrical system flaws. Karl is one of the MH moderators on this forum. rbj

 

[don_resqcapt19]

....
NEC compliant grounding will not produce electromagnetic fields unless fault current is flowing or the wiring installation is faulty, like a regrounded neutral.

I don't agree. There are cases where the code required grounding results in parallel paths for the neutral current and an increase in the electromagnetic fields under normal conditions.

 

[SG-1]

I don't agree. There are cases where the code required grounding results in parallel paths for the neutral current and an increase in the electromagnetic fields under normal conditions.

Don, please educate me. Are you thinking about ground loops in IT or audio applications where equipment is powered from different branch circuits ?

 

[Smart $]

Don, please educate me. Are you thinking about ground loops in IT or audio applications where equipment is powered from different branch circuits ?

Grounding to metal water supply lines, where the metal is electrically continuous to neighboring service(s) also grounded to the water supply. This makes parallel path(s) back to the source for neutral current.

 

[SG-1]

Grounding to metal water supply lines, where the metal is electrically continuous to neighboring service(s) also grounded to the water supply. This makes parallel path(s) back to the source for neutral current.

Thanks, I was not thinking about a common water pipe. Would there not have to be mis-wiring or a fault to cause current in the water pipe or at a well casing ? Or is the neighborhood imbalance flowing all the time through the plumbing system ?

 

[nakulak]

Are there any special scenarios that are acceptable with respect to the standard electrical service grounding (continuous conductor from service to ufer (ground rod to water service pipe entrance) and bonding (hot-cold-gas) that would make any differences regarding the concerns that people have about the EMF effects. Also, are there any recommended websites regarding the whole issue of EMF and residential electrical wiring method recommendations to minimize the potential effects of EMF?

As indicated by answers above, there are known practical and accepted methods for minimizing EMFs in wiring installations. However, reduction of EMFs, while sometimes a byproduct of best practice installations, is not necessarily a product of an NEC compliant installation, nor is it specifically mandated by the NEC. Furthermore, there is abundant speculation as to the level of EMFs that affect humans and animals, and although some research has been done, not enough research,agreement, or standardization has been accomplished (in my opinion). So "the concerns that people have about the EMF effects" will continue unabated, in the absence of any significant standardization toward the development of industry standard practices for abatement or mitigation, regardless as to current best practice or code minimum installation practices (in my opinion).

 

[don_resqcapt19]

Thanks, I was not thinking about a common water pipe. Would there not have to be mis-wiring or a fault to cause current in the water pipe or at a well casing ? Or is the neighborhood imbalance flowing all the time through the plumbing system ?

In this type of installation the water pipes and the service grounded conductor are in parallel and part of the normal neutral current will be flowing on the water pipe. It is not unusual to have 20% or more of the grounded conductor current on the water pipes. Another case where we have the same issue is cable TV were the shield is bonded to the electrical grounding system at each house creating another parallel path.
In the case of just a well casing there will not be near as much current as in the case of a common metal underground water piping system. With the well casing the earth itself is the parallel path, but with the common metal water piping system the metal piping is the parallel path.

 

[suemarkp]

Are there any special scenarios that are acceptable with respect to the standard electrical service grounding (continuous conductor from service to ufer (ground rod to water service pipe entrance) and bonding (hot-cold-gas) that would make any differences regarding the concerns that people have about the EMF effects. Also, are there any recommended websites regarding the whole issue of EMF and residential electrical wiring method recommendations to minimize the potential effects of EMF?

Isn't the main issue keeping all the conductors of a circuit together? That will occur in modern wiring methods. But the old knob-and-tube can have neutrals on one side and ungroundeds on the other. Also, retrofit grounds taking some arbitrary path to a water pipe could also play a part.

I don't tihnk we can do much about what is upstream of the main disconnet (water pipe and dirt paths).

 

[SG-1]

I don't tihnk we can do much about what is upstream of the main disconnet (water pipe and dirt paths).

A dielectric union or PVC will take care of the water pipe. The dirt is another story.

 

[SG-1]

Thanks Don, for keeping me straight. I realized later after giving more serious thought that some part of the neutral current had to be circulating because of the POCO primary neutrals. I now have an idea of the amount.

With a metal well casing would not there have to be an uncleared fault ?

 

[M. D.]

Here is a link
http://www.who.int/peh-emf/about/en/

 

[don_resqcapt19]

Thanks Don, for keeping me straight. I realized later after giving more serious thought that some part of the neutral current had to be circulating because of the POCO primary neutrals. I now have an idea of the amount.

With a metal well casing would not there have to be an uncleared fault ?

Even with the well casing there will be current flow under normal conditions, but it will be limited by the impedance of the path. You would have to do a ground resistance test of the casing to get an idea of how much current will flow, but it will divide based on the relative impedance of the paths. The casing will likely have a path impedance hundreds of times greater than that of the service neutral conductor.

 

[al hildenbrand]

With a metal well casing would not there have to be an uncleared fault ?

Actually, no. See, the amount of current in the earth between the well casing and the ground connection at the local supply transformer is current subtracted from the service neutral conductor.

If all of the occupancy load unbalance current (neutral current) were only in the service neutral conductor, then the load created net magnetic field around all of the service entrance conductors will be zero.

Except. . . and this is a real wild card. . . for the PoCo primary side neutral currents. And, since most PoCos have their distribution neutral solidly connected to the customer neutral because of the common ground at the pole or pad that the transformer is at, a neighbor, on a different transformer, with a failed neutral, under certain conditions, can have part of its unbalance current coming through this occupancy's neutral to get to the well casing.

Pulling a meter from the meter base won't interrupt all of the neutral current.

Other PoCo primary side currents will come from the distribution system currents, as well as the very Earth, itself.

 

[SG-1]

Thanks, Don & Al, I was not thinking about the metalic well casing being connected to the grounded conductor. Even with a PVC well casing the pump casing ( body ) is connected to the grounded conductor.

I see the path & what you are saying now.