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- Licensed Electrician
A three point fall of potential is what's recommended but that's expensive and not going to solve anything.
What is this stray voltage problem you are having?
Utilities Transformer Ground Connection
- Thread starter Joseph P.
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A three point fall of potential is what's recommended but that's expensive and not going to solve anything.
What is this stray voltage problem you are having?
kwired
Electron manager
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- NE Nebraska
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- EC
He mentioned stray voltage problem in OP. But driving more rods probably only masks the real problem.
mbrooke
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True, and I've even heard that it can make it worse- though not sure how to be honest.
mivey
Senior Member
Three point.
The clamp is prone to error and unverifiable without a different test. It is not a stand-alone solution.
mivey
Senior Member
You da man!
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- Placerville, CA, USA
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- Retired PV System Designer
But for ground electrodes extending over a large area, such as a UFER, the three point test involves clear distances that may not accessible in most installations.
A house in the middle of a several acre lot with no metallic conduit or water or sewer lines might qualify.
It literally has to "stand alone". :angel:
mobile
Joseph P.
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- Long Beach, NY USA
I am trying to reduce the high EMF field in the house due to the Romex wiring. Near having to live off the grid due to nerve damage from Lyme disease. The engineer who has been advising me said, first to get the ground system below 5 ohms if you can, this will help reduce the EMF field in the house and all the shielding products used need a low ohm ground to work well. It cut the EMF approx. 75%, which was good, but still need to do more. I checked the utilities ground while I had the meter and it was 470 ohms. Separate from our system, I feel it would be good if not just for the surge protection, for the utility's ground system to be at least near what Mike Holt said the NEC urges you to shoot for when burying ground rods.
- Location
- Placerville, CA, USA
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- Retired PV System Designer
For the very specific goal of reducing environmental electric and msgnetic fields the twisting of wires into supply/return pairs is cheaper and easier than trying to shield isolated wires.
A good single point connection between EGC and GES networks will do far more to help you than getting a low resistance earth (dirt) connection.
A UFER ground gives you the added benefit of an equipotential plane under the house.
Twisting Romex (NM) when installing is a lot easier than trying to retrofit the twist. Ordinary electricians who achieve perfect aesthetics by keeping their NM flat are doing you a disservice.
mobile
A good single point connection between EGC and GES networks will do far more to help you than getting a low resistance earth (dirt) connection.
A UFER ground gives you the added benefit of an equipotential plane under the house.
Twisting Romex (NM) when installing is a lot easier than trying to retrofit the twist. Ordinary electricians who achieve perfect aesthetics by keeping their NM flat are doing you a disservice.
mobile
Joseph P.
Member
- Location
- Long Beach, NY USA
I do a body voltage test, where you plug the black lead of the meter into a ground, set the meter to AC volts and hold the red lead in your hand, while you yourself are insulated from the ground. What ever the voltage the meter is reading from the field near you should skim off to zero when you ground yourself. It does that near the house, but as you get closer to the utility pole which has the transformer on it, (within 15 feet) if you do the same test, when you ground yourself, the voltage doubles. This was happening closer to the house until the house ground system's ohms were lowered from 215 ohms to 5 ohms. No one would usually care about this unless they have EMF sensitivity like I do. Lowering the resistance on the house's ground system reduced the EMF field in the house by approx. 75%.
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- Placerville, CA, USA
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- Retired PV System Designer
Congratulations on this experiment.
I think that a UFER ground, even without a reduction in earth resistance would have a similar effect if you are on a concrete slab.
mobile
I think that a UFER ground, even without a reduction in earth resistance would have a similar effect if you are on a concrete slab.
mobile
mbrooke
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I hate to say it but it will not reduce any EMFs in home wiring. In fact the magnetic fields may go up inside your home around the service because POCO neutral current now has a new low impedance path through the earth back to the substation- which will be using your grounding system and service neutral- both of which are next to your home.
If you want to reduce magnetic fields in home wiring there are 4 major factors:
1. By far the biggest and most major contributors to EMFs are wiring errors. Making sure neutrals are not crossed between circuits and that there are no standing neutral to ground faults on circuits will slash magnetic fields by 95% easily.
2. Magnetic fields can further be reduced by running twisted current carrying conductors. Running MWBC will further help. This of course must be done during new construction or renovations.
3. Static fields can be reduced by using metal conduit or steel armored cable. This is of course new construction/renovation to implement.
4. Killing power from the circuit breaker panel to general use circuits when not being used.
mbrooke
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Was the reduction in static or magnetic fields? How are you measuring them?
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- Licensed Electrician
Call me skeptical. The most important thing in keeping low levels of EMF in a house is making sure there are no net currents, this is achievable with Romex and properly wired circuits. What goes on out by the transformer is low impact compared to the inside of the house.
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- Licensed Electrician
I agree.
In regards to Romex, twisting the wires is ideal but the construction of regular Romex keeps the conductors close enough to each other that twisting isn't a dramatic improvement in reduction of magnetic fields.
mbrooke
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FIFY :thumbsup::thumbsup: Although last time I handled 14-3 and 12-3 a lot of it looked like 14-2 and 12-2 :rant:
peter d
Senior Member
- Location
- New England
:happyno::happyno:
3/C NM cable is no longer twisted, it is parallel construction with the jacket extruded over just like regular 2/C cable. Only MC and other armored cable is still twisted construction.
mbrooke
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There is a lot of fiction regarding EMFs out on the net which covers up fact. Some of it is the byproduct of ignorance, some of it people trying to sell products, others trying to cover up truth. To the people who really have electromagnetic hyper sensitivity are left swimming in an ocean of fluff and placebo.
- Occupation
- Licensed Electrician
No. I meant that regular 14 2 doesn't need twisting to reduce magnetic fields.
kwired
Electron manager
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- NE Nebraska
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- EC
I assume when you say plug one lead into a ground - you are talking about connecting it to a grounded conductor of the wiring system.
If so you are reading voltage drop on the grounded conductor along with capacitively coupled voltage between you (which you are and extension of the grounded conductor, and earth. Reduce the amount of voltage drop imposed on the grounded conductor and your measurements will reduce as well - but the problem is the voltage drop might be an issue with POCO's MGN and not a problem with your service.
Because they use a MGN system you will likely always see some voltage here, their MGN is bonded at the transformer that supplies your service to the secondary neutral of that transformer, any voltage drop on the MGN is passed on through and is present on everything connected to the grounded service conductor - which includes all equipment grounding conductors and frames of equipment and appliances in your home.
mbrooke
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And you are confirming what I just said- yet shaking your head as though I was incorrect :blink:
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