EMF's in my panel

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electricalperson

electricalperson

Senior Member
Location
massachusetts
i went to my panel in my house and i had a very high EMF reading on my gaussmeter. the panel is a 100 amp 120/240 volt challenger main panel.

the service is grounded only at the water pipe inside. the water pipe coming into the house is copper and its all grounded properly and i dont have ground rods.

i measured current on phase A and B i had 0.5 amps on one phase and 5 on the other. i had a ~4.2 amps on the neutral and .3 on the GEC.

i believe all is normal and the EMF's are coming from the net current produced by unbalanced neutral current because some of it is going down the water pipe.

am i correct with this? just trying to see if i understand everything properly
 
electricalperson

electricalperson

Senior Member
Location
massachusetts
i forgot to add that when i encircled the SEU cable with my amprobe it did have a net current of .3. the GEC is right near the SEU so i removed staples and encircled both the SEU and the GEC and had a reading of 0.0
 
electricalperson

electricalperson

Senior Member
Location
massachusetts
Pierre C Belarge said:
That is really high. Are you sure you are using this correctly?

Are there any flourescent fixtures nearby or other electronic devices?
Click to expand...

i will try to post pictures tommorw. the readings will be different but you will see the gauss range. im sure im using the gaussmeter correctly. i get very high milligauss readings off of the service drop coming down the house
 
W

wptski

Senior Member
Location
Warren, MI
electricalperson said:
i went to my panel in my house and i had a very high EMF reading on my gaussmeter. the panel is a 100 amp 120/240 volt challenger main panel.

the service is grounded only at the water pipe inside. the water pipe coming into the house is copper and its all grounded properly and i dont have ground rods.

i measured current on phase A and B i had 0.5 amps on one phase and 5 on the other. i had a ~4.2 amps on the neutral and .3 on the GEC.

i believe all is normal and the EMF's are coming from the net current produced by unbalanced neutral current because some of it is going down the water pipe.

am i correct with this? just trying to see if i understand everything properly
Click to expand...
I didn't get the MSI-95 kit , only the M95 sensor itself, cord and Riley's book. I get high EMF at my PB too. You have a mass of neutral wires and hot wires close together. Your picking up a neutral from a different hot. I think that it's normal.

Ever try to measure EMF on the circuit that has a motor on it like a furnace blower motor? See what you get if that circuit has some receptacles on it, right at the receptacle. You can even tell if it the end of the line by the difference from top to bottom on the duplex. Nothing in the book at all about types of loads.

Use the sensor on a scope and you'll see the linear/non-linear load waveforms.
 
electricalperson

electricalperson

Senior Member
Location
massachusetts
ok guys heres pictures from today. sorry for the bad quality i taken it on my cell phone. the readings might be a little off because i have the dryer running but you get the gist of it.


this is the EMF reading with the MSI 95 and the meter it came with.
gauss2.jpg



this is the current on the GEC. varied from .1 - .3
GEC.jpg



this is the neutral current
neutral.jpg



here is one of the phases
phase1.jpg



heres the other phase
phase2.jpg



zero sequence on the SEU
zeros.jpg



zero sequence with the GEC and SEU
zerogec-1.jpg
 
electricalperson

electricalperson

Senior Member
Location
massachusetts
peter d said:
I would expect the panel to have a high amount of EMF because of the concentration of all the current on the system and the relative separation of the busbars and wiring in the panel, which doesn't completely cancel out the EMF.
Click to expand...

good point. similar to how knob and tube produces a high amount of emf because its seperated

i also get a high emf off of the SEU outside my house
 
brian john

brian john

Senior Member
Location
Leesburg, VA
What's the reading a 1', 2', 3', and 4'?

Is the panel in the basement?

What's above the panel? What's behind the panel?

Is the panel near any utilized living spaces?

Have you read other residential panels?
 
electricalperson

electricalperson

Senior Member
Location
massachusetts
brian john said:
What's the reading a 1', 2', 3', and 4'?

Is the panel in the basement?

What's above the panel? What's behind the panel?

Is the panel near any utilized living spaces?

Have you read other residential panels?
Click to expand...

the panel is in the basement and the living room is right above it. behind the panel is foundation and dirt after that. the SE cable comes out and goes right into the meter socket and is covered by a big sill plate
the gauss readings go down at the varying distances. i believe its unbalanced emf's caused by the copper water being in paralell with the neutral conductor. all the houses have metal water pipes so current is going anywhere it can
 
Last edited:
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
One idea for an experiment: disconnect the water-pipe ground temporarily and repeat the measurements. That should force all service currents to remain in the cable.
 
electricalperson

electricalperson

Senior Member
Location
massachusetts
when i replace the SEU cable i will route the neutral with the ungrounded conductors. maybe that will help minimize the emf's. i wonder if i replace the meter socket outside with a meter/breaker combo and run an EGC to the panel and bond the water pipeto that the EMF's will be eliminated?
 
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