How to test a house service for emf's

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hurk27

Senior Member
Do a search for Karl Riley as he has written many books on the subject and has posted many threads on the subject, and has even designed gauss meters to use to detect EMF's, he was also a moderator on here but hasn't been active since 2010, but if you PM him he might still get an e-mail message.

While I don't have allot to say about this subject it seems to crop up now and then, but detecting high EMF's can be a good way to find other wiring problems and can be a good trouble shooting tool.

now as far as having high EMF's when the main is off about the only way I can see this is if there is a problem with the utility's main primary neutral (MGN) or a high voltage drop on it and it is using the grounding of the buildings electrode system as a return path for primary neutral current, mainly a metal city water pipe if it is common to other services.

I would check to see if you have an abnormal amount of current on the GEC to the water pipe, if it is high I would avoid disconnecting it as you could raise the voltage to earth of all that is bonded to the grounding system of this building as could cause a fire of someone being electrocuted, also check with a DVM between something grounded to the electrical system and earth, just stick a screwdriver into earth and check to the meter case, if over 10-15 volts I would call the utility immediately, as this is a sign of a failed primary MGN and can be dangerous, not very common but it happens.

Generally high EMF's are caused when both the supply and return of a circuit is not kept together in the same pathway, if the hot to a load is run separately from the neutral return from the load it will cause high EMF's or a switch leg is run to a switch by one path and the return to the load is run in another path again it will cause high EMF's but there are code compliant installs that can cause EMF, like using a 14/2 travelers between 3-ways and 4-ways instead of using 14/3, mistakes in wiring are a common cause, I have had this in a office that had many CRT computer monitors that would distort and drive the workers nuts only to find that the electricians fed the lighting with the neutral coming from one 3-way switch box and the hot from the other 3-way switch box, two totally different paths, even in conduit it will still cause EMF but we don't see this problem much any more because not many still use CRT monitors and LED monitors are un affected by EMF, but still having a good gauss meter can be a good way to find miss wired circuits, and can be a good way to find troublesome AFCI's or GFCI's that are tripping because someone grabbed the wrong neutral in a junction box.

but my jury is still out on EMF causing health problems, and I don't get into that kind of issue, I will run test but id avoid making any judgment on the issue as that is beyond my scope of work, we have been living around EMF's for many years and electricians would be the highest people that would be exposed to it, well after 37 years I have never had a problem?

Karl Riley used to have a web page not sure if he still does, I tried to google it but it just turns up listings for his books and a few other sites on the subject, try googleing Karl Riley EMF and it should turn up many web pages on the subject.
 
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brian john

Senior Member
Location
Leesburg, VA
Simple answer.

With the power on perform a zero sequence reading on the mains service feeder, L1, L2, and Neutral simultaneously.

With the power on and if they have copper water service measure current on the incoming water main, then with all power off.

With power on measure current at the grounding electrodes and with the power off.

Are they under any power lines?

How do you know EMF is an issue?

Do you have a gauss meter?
 
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