emf problem

[Trouyano]

A customer of mine bought a emf meter and believes there house is hurting them. the source of the emf seems to be the cable. i turned off the power to the whole house, same problem. i disconnected the cable from the house the problem still exists. i removed the water meter and jumper, the problem disappears. they sell couplers that isolates the house from the meter, but that is a hazard. any ideas?

that you alex

 

[petersonra]

A customer of mine bought a emf meter and believes there house is hurting them. the source of the emf seems to be the cable. i turned off the power to the whole house, same problem. i disconnected the cable from the house the problem still exists. i removed the water meter and jumper, the problem disappears. they sell couplers that isolates the house from the meter, but that is a hazard. any ideas?

that you alex

What cable are you talking about? Cable TV?

I am suspicious of the idea that low level EMF fields can be harmful. There is little in the way of actual evidence to support that contention.

It may be that the EMF is coming from an unbalanced neutral where some neutral current is flowing through the jumper and/or water meter housing. I am not real sure there is anything you can do about it, but you may be able to invoke 250.6(B).

 

[charlie b]

any ideas?

Just one, and it is going to come across as being disrespectful of your customer. Please forgive that. My idea is to tell "Chicken Little" to get rid of the EMF meter; the sky is not, in fact, falling down.

 

[charlie b]

There is little in the way of actual evidence to support that contention.

OK. He said it nicer than I did. :smile:

 

[Trouyano]

i ordered a good quality emf meter , but i think the problem is rf.

 

[don_resqcapt19]

The field is because the cable shield is required by the code to be connected in parallel with the grounded service conductor. This results in some grounded conductor current flowing on the cable shield and generates the EMF.

 

[stepke]

Hi,

you should also switch off every cell phone, take out the batteries of cordless telephones, switch off the main circuit breakers so that the whole house is off energy.

If you still receiving a signal look outside, if there`s a neighbour who does amateur radio or if there`s a police/fire station who uses radio.

Sometimes a high voltage power line above the house also can cause such signals.

Regards

Stepke

 

[hbiss]

Stepke, this is EMF not RF and Don is right on target.

This exact subject was discussed several years ago in a thread started by our resident EMF authority (his name escapes me). I don't remember whether or not we came up with a code compliant way to isolate the coax grounds to eliminate the parallel current flow.

I too agree that it's much to do about nothing, but if you insist try searching for that thread.

-Hal

 

[drbond24]

...and believes there house is hurting them.

I'm curious...what damage do they think it is doing to them?

 

[petersonra]

I'm curious...what damage do they think it is doing to them?

There is a lot of hokum out there about a lot of things.

 

[gar]

080707-1347 EST

So what is the definition of EMF and what does this EMF meter read?

From Wikipeda as a convenient source:
Electromagnetic field, a physical field
Electromotive force, a term used to characterize electrical devices

Note: for example, counter EMF is the induced voltage in a rotating DC motor armature.

Radio frequencies, infra-red, visible light, ultra violet, and x-rays are all electromagnetic fields. So why is RF excluded in one of the above comments?

So what frequency band is this EMF detector covering, and what is its sensitivity?

If I put this meter in an electric only field, or magnetic only field does it read anything?

If I go out in the middle of a farmers field, no power lines or radio transmitters near by, does it read anything? Next transmit from a 2 meter 5 W transmitter with a 1/4 wave monopole antenna 10 ft from the EMF device what does it read?

Four references:
http://en.wikipedia.org/wiki/EMF
http://en.wikipedia.org/wiki/Electromagnetic_field
http://en.wikipedia.org/wiki/Electromotive_force
http://en.wikipedia.org/wiki/Counter-electromotive_force

.

 

[drbond24]

There is a lot of hokum out there about a lot of things.

Oh, I know.

You just need to tell them that in order to protect themselves, they should construct a hat as seen below and wear it at all times while inside their house. This also has the added benefit of keeping the aliens out of their heads.

 

[stepke]

Posted from gar :From Wikipeda as a convenient source:
Electromagnetic field, a physical field
Electromotive force, a term used to characterize electrical devices

Note: for example, counter EMF is the induced voltage in a rotating DC motor armature.

Radio frequencies, infra-red, visible light, ultra violet, and x-rays are all electromagnetic fields. So why is RF excluded in one of the above comments?


to gar: Thanks.

I just wanted to give some details. EMF can have a lot of reasons and don`t wanted to critize anybody here in this forum.

I?ve been working 7 years as Technical Supp. Eng. for a companies who develops and manufatures overvoltage and lightning protection devices. This includes also emf in all its facets. I egineered a lot overvoltage protection from residential to commercial buildings. Everytime we also gave advises for the right way of grounding shields.

 

[electricalperson]

you should buy karl rileys book on EMF. very interesting. i bought the gaussmeter he reccomended and i have about 5milligauss right where i put my head down to sleep :grin: its due to the service drop on the outside wall

 

[Dennis Alwon]

you should buy karl rileys book on EMF. very interesting. i bought the gaussmeter he reccomended and i have about 5milligauss right where i put my head down to sleep :grin: its due to the service drop on the outside wall

You need to do something about those 5 mg-- not good. I believe 2 is considered safe but it depends on the distance it is from you.

Karl Riley is the name that was escaping Hal--- 5 mg is alot and I would bet if Karl Riley chimed in, his opinion on Emf's would not be as relaxed as you guys are about it.

There has been some very valid info lately on high emf's and childhood lukemia. Perhaps you all want to risk that with your child but I definitely would not want my child at risk.


I don't see where the cable is causing this problem. I thought the op said he disconnected the cable to no avail.

i disconnected the cable from the house the problem still exists.

 

[Dennis Alwon]

Here is one thread on EMF and plumbing pipes

Here is another thread on EMF's-- Karl chimes in around post 30 and on with a link to a study , etc.

 

[gadfly56]

Here is one thread on EMF and plumbing pipes

Here is another thread on EMF's-- Karl chimes in around post 30 and on with a link to a study , etc.

That link is busted. Any idea where the study is living now?

 

[Dennis Alwon]

That link is busted. Any idea where the study is living now?

Try This

http://www.bioinitiative.org/

 

[hbiss]

Ah yes! Karl Riley was the name.

So why is RF excluded in one of the above comments?

Because he was using a gaussmeter looking for magnetic fields. Correct me if I'm wrong, but I believe they are relatively insensitive to RF.

I also believe the OP said that when he disconnected the cable drop (I assume at the ground block) the reading went away. If this is the only source then it may be an easy matter to relocate the ground block and ground wire as well as the current carrying portion of the coax (that between the ground block, up the side of the house and out to the pole) farther away from areas of the house where occupants spend a great deal of time.

-Hal

 

[Dennis Alwon]

Hal -- here is part of the op statement

i turned off the power to the whole house, same problem. i disconnected the cable from the house the problem still exists.