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  1. #1
    Fred Warner's Avatar
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    Default 120 volt line-to-line dwelling wiring system

    I have been asked to comment on a case where a person is claiming hypersensitivity to normal house current and wants to have his/her dwelling wiring done as a system similar to what is permitted in Article 647 with 60 volts to ground and 120 volts line-to-line. I realize the code only permits this type of installation for commercial and industrial applications, but this person is applying for a variance.
    I have concern over the voltage drop with regard to resistance and impedance and as to whether the overcurrent protective devices will open properly.
    Any one on this forum with expertise in this area? Please comment. Thanks.

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    Default Re: 120 volt line-to-line dwelling wiring system

    I would require an investigation or documentation that all neutral to neutral and neutral to ground faults were corrected. These are located with the assistance of a gauss meter. This may also change the need for the balanced voltage system. If not consider the variance. I wouldn't worry about the voltage drop because the conductor length and loads are not changing and the voltage is the same...The operation of the overcurrent devices would have to be evaluated because you would end up with primary overcurrent devices with no direct connection to the secondary..

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

  3. #3
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    Default Re: 120 volt line-to-line dwelling wiring system

    Quote Originally Posted by Fred Warner View Post
    I have been asked to comment on a case where a person is claiming hypersensitivity to normal house current and wants to have his/her dwelling wiring done as a system similar to what is permitted in Article 647 with 60 volts to ground and 120 volts line-to-line. I realize the code only permits this type of installation for commercial and industrial applications, but this person is applying for a variance.
    I have concern over the voltage drop with regard to resistance and impedance and as to whether the over current protective devices will open properly.
    Any one on this forum with expertise in this area? Please comment. Thanks.
    Fred

    I mostly agree with Roland but I also have to add this.

    Before the case went or goes forth is anyone trying to prove or disprove the outlandish complaint.

    Its not like this person is living under power lines holding up florescent bulbs and glowing.

    Has her or his home been tested for possible flaws in installation and many improperly grounded devices.

    I cannot believe this is going forward at all. There is just about no evidence that normal houise wiring and current has any real affects on anyone that I can find.

    Forgive me for the reply but I cannot even start thinking about what the person wants with out thinking that their own wiring is a little screwed up. I think they need a human rewire job, not the wiring in there home.

    Just my opinion. Sometimes it is best if I just read and shake my head.


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    Default Re: 120 volt line-to-line dwelling wiring system

    Quote Originally Posted by Fred Warner View Post
    I have been asked to comment on a case where a person is claiming hypersensitivity to normal house current and wants to have his/her dwelling wiring done as a system similar to what is permitted in Article 647 with 60 volts to ground and 120 volts line-to-line. I realize the code only permits this type of installation for commercial and industrial applications, but this person is applying for a variance.
    I have concern over the voltage drop with regard to resistance and impedance and as to whether the overcurrent protective devices will open properly.
    Any one on this forum with expertise in this area? Please comment. Thanks.
    Hello Fred,

    I'm not sure I fully understand the situation. Is this in litigation as suggested by Ted or is this a situation that a person has a medical condition and is attempting to make their home comfortable?

    You indicated they are looking for a variance. I assume this means from the local AHJ ?

    If this persons needs a special electrical system for their residence, it should be designed by a qualified design professional such as a P.E. that specializes in electrical systems. It should be installed by qualified installers, tested and signed off by the P.E. Under these conditions, I would think the variance would be granted.

    That's my take on it.

    Sincerely,

    Corey


  5. #5
    Fred Warner's Avatar
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    Default Re: 120 volt line-to-line dwelling wiring system

    Quote Originally Posted by Corey Friedman View Post
    Hello Fred,

    I'm not sure I fully understand the situation. Is this in litigation as suggested by Ted or is this a situation that a person has a medical condition and is attempting to make their home comfortable?

    You indicated they are looking for a variance. I assume this means from the local AHJ ?

    If this persons needs a special electrical system for their residence, it should be designed by a qualified design professional such as a P.E. that specializes in electrical systems. It should be installed by qualified installers, tested and signed off by the P.E. Under these conditions, I would think the variance would be granted.

    That's my take on it.

    Sincerely,

    Corey
    The person is claiming a special hypersensitivity to electrical current and wants his/her place wired in much the same way a recording studio is wired. They are seeking a variance to the 2002 NEC Article 647 which states that this type of wiring is only permitted for commercial and industrial occupancies. I serve as chairperson on this variance board and would like as much input as I could get prior to making any recommendations to fellow board members.
    We will require the services of a design professional, of course. I'm just looking for as much information as I can get prior to the hearing.
    Thanks to all of you, so far, for responding.
    For some reason, I'm of the opinion that voltage drop on a 60 volt branch circuit will seriously affect tripping of overcurrent devices. Please further enlighten.


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    Default Re: 120 volt line-to-line dwelling wiring system

    Quote Originally Posted by Fred Warner View Post
    The person is claiming a special hypersensitivity to electrical current and wants his/her place wired in much the same way a recording studio is wired. They are seeking a variance to the 2002 NEC Article 647 which states that this type of wiring is only permitted for commercial and industrial occupancies. I serve as chairperson on this variance board and would like as much input as I could get prior to making any recommendations to fellow board members.
    We will require the services of a design professional, of course. I'm just looking for as much information as I can get prior to the hearing.
    Thanks to all of you, so far, for responding.
    For some reason, I'm of the opinion that voltage drop on a 60 volt branch circuit will seriously affect tripping of overcurrent devices. Please further enlighten.
    Hi Fred,

    Now I understand.

    If it were up to me, if a P.E. would write a specification and confirm no unusual hazards would exist, I would be in favor of the variance.

    If this person is under medical care for this condition it seams to me that it is the duty of the AHJ to grant the permission provided the design professional can provide a safe system.

    Good luck in making your decision.

    Sincerely,

    Corey


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    Default Re: 120 volt line-to-line dwelling wiring system

    You still have 120 volts--on a standard receptacle for instance it would read the same on a voltmeter from line to neutral. It would however read 60 to ground from the neutral and 60 from the neutral side to ground. There would be no connection between the receptacle neutral and equipment ground. In essence there would be two hots such as with 220 volts..The problem then becomes providing enough current in an overload or fault condition to trip an overcurrent device since the source becomes the one-to-one transformer. So I am thinking there will have to be some supplemental fusing to make it work safely..

    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

  8. #8
    Fred Warner's Avatar
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    Default Re: 120 volt line-to-line dwelling wiring system

    Quote Originally Posted by Corey Friedman View Post
    Hi Fred,

    Now I understand.

    If it were up to me, if a P.E. would write a specification and confirm no unusual hazards would exist, I would be in favor of the variance.

    If this person is under medical care for this condition it seams to me that it is the duty of the AHJ to grant the permission provided the design professional can provide a safe system.

    Good luck in making your decision.

    Sincerely,

    Corey
    Thanks for your input.
    Just as soon as I'm convinced that the VD and OCPD mesh, I'll feel a lot better about it. I'm sure with an experienced P.E. the variance will go forward. The entire staff is leaning this way.


  9. #9
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    Default Re: 120 volt line-to-line dwelling wiring system

    As Roland is saying, you will not have a neutral as such, you will have (basically) a 240 circuit running at 120 volts with two ungrounded conductors, each of which (does not matter which) is 60 volts to ground.

    The electrical engineer is a must as one thing he would need to make sure of is that all equipment is rated for an intentional voltage neutral to ground, and that the rating for such intentional voltage is adequate.

    She may well be required to have special appliances which are designed to operate 60 volts above ground.

    Instead of using single pole breakers you will be using double pole breakers for all circuits, and both ungrounded conductors will be required to be opened at the same time.

    All two-prong polarized equipment is designed for the identified prong to be at (or very near) ground potential because it would be operating with that connected to the grounded conductor. Think of a hair dryer, now operating with that conductor at 60 volts above ground, electric shavers now operating with that conductor at 60 volts above ground, same for the can opener, mixer, etc., used in the kitchen near the sink.

    The electrical engineer would need to verify the listing and labeling of all equipment and the rating of the "grounded" conductor terminal operating at 60 volts above ground.

    Some serious consideration needs to be given this before its approval, however, if all questions raised where accounted for and addressed by the engineer, when the variance is given, I would require that ALL devices, ALL equipment and appliances, the electrical panel, etc., ALL be permanently marked and labeled with a warning that this structure is wired with that 60 volt / 120 volt wiring system and that all normally grounded conductors were 60 volts above ground.

    Actually complying with requirements of 647 will be difficult, such simple things as plugging a table lamp into a receptacle outlet will not be permitted, to wit:
    - 647.7 Receptacles.
    - - (A) General. Where receptacles are used as a means of connecting equipment, the following conditions shall be met:
    - - - (1) All 15- and 20-ampere receptacles shall be GFCI protected.
    - - - (2) All receptacle outlet strips, adapters, receptacle covers, and faceplates shall be marked with the following words or equivalent:
    - - - - - - - WARNING TECHNICAL POWER
    - - - - - - Do not connect to lighting equipment.
    - - - - - - - For electronic equipment use only.
    - - - - - - - - - - - 60/120 V. 1ac
    - - - - - - - - - - - GFCI protected
    - - - (3) A 125-volt, single-phase, 15- or 20-ampere-rated receptacle having one of its current-carrying poles connected to a grounded circuit conductor shall be located within 1.8 m (6 ft) of all permanently installed 15- or 20-ampere-rated 60/120-volt technical power-system receptacles.
    - - - (4) All 125-volt receptacles used for 60/120-volt technical power shall have a unique configuration and be identified for use with this class of system. All 125-volt, single-phase, 15- or 20-ampere-rated receptacle outlets and attachment plugs that are identified for use with grounded circuit conductors shall be permitted in machine rooms, control rooms, equipment rooms, equipment racks, and other similar locations that are restricted to use by qualified personnel.

    I would think that it would be better and simpler to provide shielding for each circuit and leave the wiring method as -0- volts neutral to ground and 120 volts ungrounded conductor to grounded conductor.

    I can see all kinds of complications with this 60 volt / 120 volt wiring being done in a house where the use is by unknown and untrained persons.

    Jerry Peck, Construction / Litigation Consultant
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  10. #10
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    Default Re: 120 volt line-to-line dwelling wiring system

    I really hate to open this up but I am still curious as to why the board is entertaining this idea.

    Did this individual come to the board with , well, a doctors note?? May sound stupid but that would be my first attempt to ascertain that there is actually a reason for doing this. These folks will more than likely not live in this home for ever and one would think there would be a need for permanent placards to be placed to identify the changes to the electric system. I can see the future home owner wanting to make some basic changes and screw things all up.

    Just curious Fred. This whole thing for making such decisions is generally based on the need. Not just someone walking in off the street and saying they have a hypersensitivity to household wiring.

    Any variance I have ever seen given as far as even entertaining the idea of a variance is to give reason for the variance with something more than basically an "I have an allergy to household wiring" without something to back it up. I don't need to know specifics. I would just like to know if someone could even get a doctor to write this down. Not a psychiatrist

    Not questioning you directly Fred but again I am trying to absorb the reasoning.


  11. #11
    Fred Warner's Avatar
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    Default Re: 120 volt line-to-line dwelling wiring system

    Quote Originally Posted by Roland Miller View Post
    I would require an investigation or documentation that all neutral to neutral and neutral to ground faults were corrected. These are located with the assistance of a gauss meter. This may also change the need for the balanced voltage system. If not consider the variance. I wouldn't worry about the voltage drop because the conductor length and loads are not changing and the voltage is the same...The operation of the overcurrent devices would have to be evaluated because you would end up with primary overcurrent devices with no direct connection to the secondary..
    Roland: Wouldn't there be a normal 120/240 volt panelboard with normal 15 and 20 ampere double-pole breakers installed on the secondary side of the x-fmr ?


  12. #12
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    Default Re: 120 volt line-to-line dwelling wiring system

    Quote Originally Posted by Ted Menelly View Post
    Fred

    I mostly agree with Roland but I also have to add this.

    Before the case went or goes forth is anyone trying to prove or disprove the outlandish complaint.

    Its not like this person is living under power lines holding up florescent bulbs and glowing.

    Has her or his home been tested for possible flaws in installation and many improperly grounded devices.

    I cannot believe this is going forward at all. There is just about no evidence that normal houise wiring and current has any real affects on anyone that I can find.

    Forgive me for the reply but I cannot even start thinking about what the person wants with out thinking that their own wiring is a little screwed up. I think they need a human rewire job, not the wiring in there home.

    Just my opinion. Sometimes it is best if I just read and shake my head.
    Ted, sorry for the delay in answering your post. The Board will certainly recommend a survey of existing magnetic field conditions. Before any consideration should be given to allowing a balanced voltage system at 60/120 to replace what is essentially a balanced voltage system at 120/240 at the point of source, a thorough examination of all interior wiring should be conducted. All switch loops and MWBC's should be discontinued and a host of other remedies, as well.


  13. #13
    Fred Warner's Avatar
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    Default Re: 120 volt line-to-line dwelling wiring system

    Quote Originally Posted by Ted Menelly View Post
    I really hate to open this up but I am still curious as to why the board is entertaining this idea.
    Ted, The Board must review all applications for variances.

    Quote Originally Posted by Ted Menelly View Post
    Did this individual come to the board with , well, a doctors note?? May sound stupid but that would be my first attempt to ascertain that there is actually a reason for doing this. These folks will more than likely not live in this home for ever and one would think there would be a need for permanent placards to be placed to identify the changes to the electric system. I can see the future home owner wanting to make some basic changes and screw things all up.
    Yes. There is a clear medical need. A covenant would be written into the deed that would require restoration to normal 120/240 volt wiring upon sale or transfer. All other code matters would be complied with except those that would be varied by the Board.

    Quote Originally Posted by Ted Menelly View Post
    Just curious Fred. This whole thing for making such decisions is generally based on the need. Not just someone walking in off the street and saying they have a hypersensitivity to household wiring.

    Any variance I have ever seen given as far as even entertaining the idea of a variance is to give reason for the variance with something more than basically an "I have an allergy to household wiring" without something to back it up. I don't need to know specifics. I would just like to know if someone could even get a doctor to write this down. Not a psychiatrist

    Not questioning you directly Fred but again I am trying to absorb the reasoning.
    Not a problem. Petitioner is legit.


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    Default Re: 120 volt line-to-line dwelling wiring system

    "Wouldn't there be a normal 120/240 volt panelboard with normal 15 and 20 ampere double-pole breakers installed on the secondary side of the x-fmr ?"

    Fred--the only systems I have see and am familiar with are for hospital operating rooms. The Isolation transformer and the overcurrent devices and well as some alarm and instrumentation were all contained in one unit. I know this is a common installation for professional recording studios but am not familiar with it. Sorry


    "Get correct views of life, and learn to see the world in its true light. It will enable you to live pleasantly, to do good, and, when summoned away, to leave without regret. " Robert E. Lee

  15. #15
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    Default Re: 120 volt line-to-line dwelling wiring system

    Would it not be cheaper to convert the home from AC TO DC. And just replace all the appliances ?

    Then if the ower moves they can just take everything to the new home.

    Best

    Ron


  16. #16
    Fred Warner's Avatar
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    Default Re: 120 volt line-to-line dwelling wiring system

    Quote Originally Posted by Ron Bibler View Post
    Would it not be cheaper to convert the home from AC TO DC. And just replace all the appliances ?

    Then if the ower moves they can just take everything to the new home.

    Best

    Ron
    There have actually been some meaningful discussions with regard to this idea.


  17. #17
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    Default Re: 120 volt line-to-line dwelling wiring system

    Does electricity know the color of the wire insulation? Or, is it somehow more dangerous if it's in a wire of the 'wrong' color?

    I ask these questions, because it helps illustrate a point. The only reason that, say, using a green wire as a 'hot' is dangerous is because we have a convention, a common practice, that we follow. Vary from this practice, and you introduce an element of uncertainty, and set the stage for creating a hazard.

    As fot the topic of the post ... yes, there is some value is checking to make sure that everything is done properly to begin with.

    Even more valuable is telling this nut-job to go pound sand. His 'sensitivity' is purely imaginary, and it serves him ill to cater to his psychosis. You are also setting the stage for creating very real danger to everyone who may work on the system.

    There is absolutely no evidence to support his claims .... if he is so 'sensitive,' cut the power and cook with wood!


  18. #18
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    Default Re: 120 volt line-to-line dwelling wiring system

    Quote Originally Posted by John Steinke View Post
    As for the topic of the post ... yes, there is some value in checking to make sure that everything is done properly to begin with.

    Even more valuable is telling this nut-job to go pound sand. His 'sensitivity' is purely imaginary, and it serves him ill to cater to his psychosis. You are also setting the stage for creating very real danger to everyone who may work on the system.

    There is absolutely no evidence to support his claims .... if he is so 'sensitive,' cut the power and cook with wood!
    Here is an excerpt from an interesting article:

    So what exactly is "dirty electricity"?

    The electricity produced by power stations which is delivered to your home wall outlets is designed to be at low frequencies, typically 50 or 60Hz depending on which country you live in. The frequency in North America is 60Hz, whilst in the United Kingdom it is 50Hz, for example. At this frequency, relatively low levels of electromagnetic pollution radiates from wires and electrical equipment.

    Unfortunately, the electricity supply is reportedly becoming contaminated more and more by higher frequency, higher energy electromagnetic fields (EMF's). It is this contaminated electricity that is referred to as dirty electricity.

    Dirty electricity comes from a number of different sources. It can be picked up by the power lines delivering electricity to your home from the utility. Electrical devices in your own home can also generate substantial amounts of dirty electricity. According to www.dirtyelectricity.ca, computers, TVs, florescent and halogen lighting and virtually all of today's energy-efficient electronic devices generate high levels of high frequency electromagnetic fields. Much of this dirty electricity is a result of transformers converting the low frequency AC current from the outlet to the low voltage DC power used to power all of our electronics. So unfortunately, although modern electronic devices are increasingly energy efficient, they also generate high levels of dirty electricity with potential harmful consequences for our health.

    The dirty electricity produced by the multitude of electronic devices in our homes and in public buildings can then be conducted throughout these building's electrical wires and devices. These high frequency EMF's are much more dangerous than your home wiring's low frequency (50/60Hz) EMF's because they can actually radiate out from the wires in the form of a radio wave. They can extend into radio frequencies above several megahertz (1 MHz = 106 Hz) and can often get into the microwave range of the electromagnetic spectrum, it has been reported.

    Dirty electricity containing high frequency radio frequency surges can carry hundreds, even a thousand, times the energy of the standard low frequency electrical supply. Due to the high frequencies, this energy can penetrate the human body and potentially cause a lot of harm.

    Other sources of electromagnetic pollution include ground current and radio frequency radiation. Ground current is the result of utility companies neutral wires not having the capacity to carry the electricity back to the power plant after it has passed through the power grid and your home's wiring. If you can remember your school physics classes, you might remember that for electricity to flow a complete circuit is needed. The circuit therefore needs to return to the power station after it passes through your home. Nowadays the wires returning to the power stations can't carry all the electrical current that they need to so the current instead passes through the surface of the Earth. This electrical energy which likely already contains high frequency contamination can pick up more as it goes along and may enter the wiring system of your home and other buildings. This adds to the dirty electricity already present there. In addition to the radio frequency EMF's generated by dirty electricity as described above, a growing number of electronic devices use RF energy directly to fulfill their purpose. These devices include cell phones, cordless home phones, and wireless internet equipment, contributing to the electromagnetic pollution already present in the home, school or office.

    In 2005 a press release issued by the World Health Organization announced that Electrical Hypersensitivity (EHS) is a "growing worldwide [COLOR=#009900! important][COLOR=#009900! important]health [COLOR=#009900! important]concern[/COLOR][/COLOR][/COLOR]". As noted by the author of this latest article from Trent University, EMF's have also been linked to diseases such as diabetes, multiple sclerosis , ADD/ADHD, [COLOR=#009900! important][COLOR=#009900! important]depression[/COLOR][/COLOR] and chronic fatigue syndrome, as well as to many of the sleep disorders plaguing western society. The effect is thought to depend on an individual s sensitivity, as well as the magnitude, duration of exposure, and path the waves take through one's body.

    What are Graham-Stetzer filters and how can they help?

    GS filters are the most common tools used to reduce dirty electricity in buildings. These filters are based on 100 year old electromagnetic theories and power engineering principles and are designed to filter out harmful high frequencies from the power supply, essentially cleaning the electricity. The filters work by providing high frequency electrical currents with a direct low resistance path from the live wire to the neutral wire. This prevents dirty electricity from entering the buildings wiring system and being amplified by electronic devices. GS filters are most effective at reducing dirty electricity in the frequency range of 4kHz to 100kHz.

    Dr. Havas reports that GS filters have been fitted in many schools in Canada and most have reported widespread improvements in the health of students. In particular, symptoms of asthma and ADD/ADHD have shown large improvements. It has also been reported that general school performance of students as a whole has increased, with increased attention and concentration, although this is obviously anecdotal at this point. Having said that, the schools used GS meters to measure electromagnetic pollution levels both before and after installation of GS filters in the buildings, so this makes a strong case for widespread health improvements being due to the reduction in dirty electricity.

    At present the health effects of dirty electricity and electromagnetic pollution are unclear, but an increasing number of people appear to be affected by the electrical devices that surround us. It is therefore good to know that Dr. Havas and other researchers are taking notice and calling for more research in this area. Environmental illnesses such as fibromyalgia and chronic fatigue syndrome appear to result from the body being overwhelmed by environmental stressors, and electromagnetic pollution could very well be one of these. The anecdotal reports of success using GS filters in Canadian schools and elsewhere offer promise for those afflicted by health issues related to this pollution. It would therefore seem worthwhile to have your home and/or work environments assessed for electromagnetic pollution using GS meters or similar equipment, and have filters installed if the results call for it.


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    Default Re: 120 volt line-to-line dwelling wiring system

    Fred,

    Seems simple enough for those high frequency problems to simply install a low pass filter which, say, allows frequencies of under 100 Hz to pass and attenuates down frequencies above 100 Hz, that would also reduce problems with harmonics, which is another problem caused by all of the electrical and electronic equipment in use today in homes, businesses, schools, and other places.

    Because of the nature of filters and their effect bandwidths, etc., it may take a collection of connected low pass filters to first allow low pass of 10 kHz, a subsequent filter allows a low pass of 1 kHz, then a final low pass filter allows for a low pass of 100 Hz.

    I've been out of the electronics field for about 40 years, but we could have done that back then, so I'm sure it would be even easier to do today.

    Heck, I worked in a "clean room" which was enclosed with gold strand screening (yes, the screening was made from 24 kt gold wire strands) such that the inside of the room was "clean" (without interference noise) for testing sensitive electronic equipment. Don't get me wrong, not saying one would have to protect an entire house that way, but when extreme measures are needed, extreme measures are available.

    For "dirty electricity", seems like a simple set-up of low pass filters would do very nicely, and very inexpensively.

    If extreme measures were needed, she/he could have a "clean room" constructed within the bedroom so he/she could sleep and have a place to sit, read, etc., without having to deal with the hypersensitivity to electro-magnetic fields.

    Years ago there was concern raised over LF EMF and ELF EMF (Low Frequency EMF and Extremely Low Frequency EMF, ELF = 30-300 Hz, not sure that LF and ELF ever had 'standardized frequency ranges) and for which there was research supporting both the pro and con sides of the issue.

    I had a triaxial milligauss meter, not sure where it went, but I still have my single axis milligauss meter somewhere (saw it not too long ago). A triaxial meter is best and most efficient when trying to measure EFL EMF (not even sure they make a single axis meter anymore).

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  20. #20
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    Default Re: 120 volt line-to-line dwelling wiring system

    Lived in a house with this type of wiring. Both wires were black and I wondered which was neutral and found out the hard way that the answer was neither. It was also knob and tube wiring (was it ever referred to as ring and pin?).


  21. #21
    Fred Warner's Avatar
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    Default Re: 120 volt line-to-line dwelling wiring system

    Just thought I'd let posters know more about the matter. I'm no longer serving on the Board having retired in November of '09.

    Here it is:

    Discussion Regarding Balanced Voltage.

    This is a letter I wrote to my fellow Board members discussing a hearing before us regarding a person's extreme sensitivity to the presence of voltage:

    In theory, a code-compliant balanced-voltage technical power system could be safe in a dwelling, but the proper design and installation would be of paramount concern. As an example, a standard 120-volt load becomes a 'line-to-line' load rather than 'line-to-neutral' load and requires a double pole switch. Further, switch 'loops' become a nightmare when wiring for convenience using this method since all the switches are required to be double pole. Multiwire branch circuits could not be used and devices that require a grounded conductor for safety, such as a screw-shell lamp holder would not be permitted. Many common appliances would not be suitable.

    It will be beneficial to educate petitioner on the difference between current which causes magnetic fields and voltage which causes electric fields and to direct petioner's focus on correcting current issues prior to correcting voltage possibilities. Unbalanced current caused by wiring errors and code violations are probably the most significant contributing factor. Having electric fields and magnetic fields present can be minimized to safe levels by repairing problems of unbalanced current flow. For example: There is case history of a person being sensitive to magnetic fields over 2 mG who would not use the lights in her bedroom or bathroom because she was disturbed by the effect. An electrical engineer found levels as high as 30 mG in those areas. It was determined, by having a master electrician present with the engineer, that the cause of the excessive fields was the branch-circuit power source supplying the bathroom light switch box was "jumped" from a receptacle circuit, but only the ungrounded ("hot") conductor was used. The reason for this was determined to be that the original branch circuit supplying this area had an ungrounded conductor ("hot") damaged by a nail during construction rough-in and was subsequently "capped off" in the panelboard, but the ungrounded ("neutral") conductor to this original circuit was not capped off and was being used to make a circuit with the ungrounded ("hot") conductor of another circuit. This meant that the room was wired with the "hot" coming in one side of the bedroom and the neutral going back through the floor area in a stud wall in the bathroom. This created a net current loop creating high fields.

    The physics of balancing net current fields (magnetic fields) is that they actually do balance. Think of it as two waves in the sea coming from different directions, crest and trough, and when they coincide, no wave.

    My suggestion for a resolution to this variance request is as outlined below.

    1. The Board of Review would direct petitioner to have an electrical engineer conduct a Magnetic Field Survey. If there are wiring errors causing magnetic fields, the repairs could be performed on a time-and-material basis. If there are extensive problems observed, go to Step 2.


    2. If solving unbalanced current issues related to existing improper wiring methods does not provide relief for petitioner, or if there were so many such issues as to make rewiring less expensive, then have the petitioner rewire the entire system using metal-clad cables employing no mutiwire circuits or switch loops. Dwelling could be wired in such a method as to provide for a "drop in" balanced-voltage system at a later date if petitioner still experiences effects. This "drop in" method would also provide an economical way to return the house to normal voltage upon sale or transfer. Essentially you are fixing all current balance issues, installing metallic sheilding, and providing the balanced-power "drop in" skeleton.

    3. Have petitioner consider a service contract with a qualified balanced-voltage system installer.

    4. If 2 doesn't solve the problem and 3 is acceptable legally and the requisite variances from the NEC are issued, then have petitioner install the balanced power system.

    5. Resolve issues of power supply voltage for fire-and-smoke detecting system. Typically these systems are low-voltage (24 volts) with a 120 volt power source. In a balanced voltage system, consideration should be given to the listing and labeling as pertains to acceptability for use.

    Another point to consider is whether the Board should also issue a variance to 647.7(3).

    Also, bear in mind while making deliberations that currents that are not considered part of the household wiring system can also lead to magnetic fields, such as current flow on metallic water pipes, even with the power off to the home. This condition, if present, could be corrected prior to installing a balanced voltage system. Many appliances produce significant electrical and magnetic fields, even on a balanced voltage system. Residential single-phase 120/240 volt service is balanced, and with clever installation, this balance could be maintained to the point of source. For example, consider a kitchen with recessed can lighting. This room could be wired with equal numbers of cans on opposite phases all using a 14-2-2 cable with no shared neutral (two circuits).

    Other possible preconditions for the issuance of a variance might be:


    Provide variance to 647.3(1)

    The system shall be grounded as per 250.30


    Interior metal piping if present shall be bonded in accordance with 250.104(A)(4).




    All luminaires connected to the balanced voltage system shall be provided with a disconnect means as per code and all luminaires shall be listed for the purpose.


    If I can be of further assistance, please let me know.

    Yours truly,


    Frederick Warner
    Chair, Capital Region Board of Review





    Last edited by Fred Warner; 04-13-2011 at 03:51 PM.

  22. #22
    John Steinke's Avatar
    John Steinke Guest

    Default Re: 120 volt line-to-line dwelling wiring system

    Your best comment would be to assert that you are not competent to testify on this matter.

    I know I'm not. Opinions are one thing; testimony is another.


  23. #23
    Join Date
    Mar 2007
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    Default Re: 120 volt line-to-line dwelling wiring system

    Quote Originally Posted by John Steinke View Post
    Your best comment would be to assert that you are not competent to testify on this matter.

    I know I'm not. Opinions are one thing; testimony is another.
    It's also one thing to modify minor items in a house for the person living there, and something totally different to modify the electrical system in a way which is going to be unsafe for ALL other occupants and future owners for a perceived (or even real) condition like that described ... there IS A REASON for the limited uses in the NEC for those types of systems ... they are not to be installed in a dwelling unit outside a controlled system where access is ONLY BY "qualified individuals".

    I think it would be a HUGE MISTAKE to even utter a comment to the effect that 'oh, yeah, that can be done', and even worse to explain how to do it, and worse yet to encourage anyone to do it.

    There are environments which that person can live in without putting others at risk.

    Personally, it would take a lot to convince me that the condition was "real" and just not a "perceived" condition, but my position would not change even if I could be convinced that the condition was "real".

    I would suggest dual test chambers be setup, one with just such a wiring system and one with a regular 120 volt wiring system, to verify that the intended outcome would be achieved (only don't allow the person being tested to know which is which, or maybe even label them opposite as they are). I suspect the 'get better' chamber would be the one which the subject *thinks* is wired the way they want it, not which chamber is actually wired that way.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  24. #24
    Join Date
    Feb 2009
    Location
    Southern Vancouver Island
    Posts
    4,546

    Default Re: 120 volt line-to-line dwelling wiring system

    Quote Originally Posted by Jerry Peck View Post

    I would suggest dual test chambers be setup, one with just such a wiring system and one with a regular 120 volt wiring system, to verify that the intended outcome would be achieved (only don't allow the person being tested to know which is which, or maybe even label them opposite as they are). I suspect the 'get better' chamber would be the one which the subject *thinks* is wired the way they want it, not which chamber is actually wired that way.
    Easier than that, do nothing, tell the client you've fixed it, bill them heavily but tell them if they feel better in 6 months, you'll give them their money back.

    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

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