Experience with Magnetic Shielding?

classic Classic list List threaded Threaded
9 messages Options
Reply | Threaded
Open this post in threaded view
|

Experience with Magnetic Shielding?

ChrisR
Hi Guys!  New to the group, and one of the many topics I hope to learn more about is shielding magnetic fields.  Im close to the main line to the house, and the panel box in the bedroom.  I would like to use some kind of foil or other material to line outside the house wall, and panel to block some of the magnetic entering through the wall.  I hope someone has heard about this before.  Im getting a 10mg reading or higher sometimes!

Thanks guys.


Reply | Threaded
Open this post in threaded view
|

Re: Experience with Magnetic Shielding?

BiBrun
Magnetic shielding tends to be too expensive to use on a whole house.
You can't use aluminum foil, but mu-metal foil will make an improvement.
The most cost effective is silicon steel (magnet steel).  It's not a foil,
it is sheet metal.  The grain of the metal should align with the field.

From 10mG you have a long way to go.  Even to get a small area down to 2mG
would be a challenge, and ideally you want 0.02 mG or lower.

If it's coming from a power line it's pretty hopeless, although getting rid
of neutral current and ground loops can allow the field to fall off more
quickly as you move away from the lines.  This means interrupting current in
metal water pipes, disconnecting extra ground connections, gas to electric
connections.   It's good to figure out where current flows in the
neighborhood before hring a plumber.


On Sat, Jan 1, 2011 at 2:35 AM, ChrisR <[hidden email]> wrote:

>
>
> Hi Guys! New to the group, and one of the many topics I hope to learn more
> about is shielding magnetic fields. Im close to the main line to the house,
> and the panel box in the bedroom. I would like to use some kind of foil or
> other material to line outside the house wall, and panel to block some of
> the magnetic entering through the wall. I hope someone has heard about this
> before. Im getting a 10mg reading or higher sometimes!
>
> Thanks guys.
>
>  
>


[Non-text portions of this message have been removed]



------------------------------------

Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/eSens/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/eSens/join
    (Yahoo! ID required)

<*> To change settings via email:
    [hidden email]
    [hidden email]

<*> To unsubscribe from this group, send an email to:
    [hidden email]

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/

Reply | Threaded
Open this post in threaded view
|

Tolerable Blu-ray player

Marc Martin
Administrator
In reply to this post by ChrisR
Happy New Year everyone!

In the past I've mentioned that I've tried two different
Blu-ray players, but neither of them were tolerable.  Has
anyone here found a tolerable brand/model Blu-ray player?

It's not like I have a problem with HDTV -- I've got an
HD cable box, media player, and upscaling DVD player
which all cause me no problems.  Just haven't been so
lucky with Bluray players.

Thanks!

Marc
Reply | Threaded
Open this post in threaded view
|

Re: Experience with Magnetic Shielding?

ChrisR
In reply to this post by BiBrun
Hi Bill.  Thanks for your response.  I will look into the silicon steel more, as this may be a little cheaper than all this mu-metal ive been looking at!

My issue continued:  I have the power "drop-down" coming into my roof and going on the opposite wall of my shower and bedroom.  the box is pretty much  next to my head when I shower, and the highest readings.

I want to put a piece of shield(silicon steel?) in between the back of the panel box, and the shingles on my house.  its a small distance, maybe 1", but anything I can pack in that distance is best.

Is there a wrap or conduit that is good to wrap around the power lines? (of course with power company approval)

thanks.

p.s. as far as checking current to ground in the neighborhood, can you elaborate?  get a net current flow meter and walk to my neighbors houses putting it around the water/gas/ground lines?

would the catv line near the power line amplify the magnetic field?

--- In [hidden email], Bill Bruno <wbruno@...> wrote:

>
> Magnetic shielding tends to be too expensive to use on a whole house.
> You can't use aluminum foil, but mu-metal foil will make an improvement.
> The most cost effective is silicon steel (magnet steel).  It's not a foil,
> it is sheet metal.  The grain of the metal should align with the field.
>
> From 10mG you have a long way to go.  Even to get a small area down to 2mG
> would be a challenge, and ideally you want 0.02 mG or lower.
>
> If it's coming from a power line it's pretty hopeless, although getting rid
> of neutral current and ground loops can allow the field to fall off more
> quickly as you move away from the lines.  This means interrupting current in
> metal water pipes, disconnecting extra ground connections, gas to electric
> connections.   It's good to figure out where current flows in the
> neighborhood before hring a plumber.
>
>
> On Sat, Jan 1, 2011 at 2:35 AM, ChrisR <vwporscheaudi@...> wrote:
>
> >
> >
> > Hi Guys! New to the group, and one of the many topics I hope to learn more
> > about is shielding magnetic fields. Im close to the main line to the house,
> > and the panel box in the bedroom. I would like to use some kind of foil or
> > other material to line outside the house wall, and panel to block some of
> > the magnetic entering through the wall. I hope someone has heard about this
> > before. Im getting a 10mg reading or higher sometimes!
> >
> > Thanks guys.
> >
> >  
> >
>
>
> [Non-text portions of this message have been removed]
>


Reply | Threaded
Open this post in threaded view
|

Re: Experience with Magnetic Shielding?

BiBrun
The safest advice is to move.

Or for about $5k (maybe much more or less) you might be
able to get the meter moved to a pole away from the house.
Then have twisted wires (I think aluminum comes pre-twisted)
run underground to the panel.  You will still get high readings
but not as high.  Beware they may insist on upgrading the meter
to digital which could make things worse rather than better.

I just tried putting some shielding material over my panel.
The field 10' inside the house got slightly worse!

I don't quite understand your explanation of the box and shingles.

If the power company wires are twisted evenly I don't think there's
anything they can do to make it better for you, unless there is
RFI on the lines in which case you can tell them it's harmful interference
on you MFJ-856 radio and they should try to fix that.

The issue with net current is that all the current coming from
the power company on the wires should return via the neutral wire.
Usually it doesn't because it can go back through the ground rod or
pipes.  It's not obvious whether breaking those connections will
help you in the shower, but further away it can make a big difference
(unless the dominant field is from something else, like the lines on the
street).

Chances are removing all those connections will violate code, but the
grounding rules seem to be changing a lot.  As long as the neutral and
ground are bonded in the panel (which is true in the US for the most part)
you won't notice if there is no earth connection, unless the neutral wire
breaks some day.  Which you would notice in either case, but might be less
dangerous with the connections.  I've never encountered such a neutral break
but they do happen sometimes, so I've read.  But it seems unlikely unless
there is construction or rewiring being done.



On Sat, Jan 1, 2011 at 11:54 AM, ChrisR <[hidden email]> wrote:

>
>
> Hi Bill. Thanks for your response. I will look into the silicon steel more,
> as this may be a little cheaper than all this mu-metal ive been looking at!
>
> My issue continued: I have the power "drop-down" coming into my roof and
> going on the opposite wall of my shower and bedroom. the box is pretty much
> next to my head when I shower, and the highest readings.
>
> I want to put a piece of shield(silicon steel?) in between the back of the
> panel box, and the shingles on my house. its a small distance, maybe 1", but
> anything I can pack in that distance is best.
>
> Is there a wrap or conduit that is good to wrap around the power lines? (of
> course with power company approval)
>
> thanks.
>
> p.s. as far as checking current to ground in the neighborhood, can you
> elaborate? get a net current flow meter and walk to my neighbors houses
> putting it around the water/gas/ground lines?
>
> would the catv line near the power line amplify the magnetic field?
>
>
> --- In [hidden email] <eSens%40yahoogroups.com>, Bill Bruno
> <wbruno@...> wrote:
> >
> > Magnetic shielding tends to be too expensive to use on a whole house.
> > You can't use aluminum foil, but mu-metal foil will make an improvement.
> > The most cost effective is silicon steel (magnet steel). It's not a foil,
> > it is sheet metal. The grain of the metal should align with the field.
> >
> > From 10mG you have a long way to go. Even to get a small area down to 2mG
> > would be a challenge, and ideally you want 0.02 mG or lower.
> >
> > If it's coming from a power line it's pretty hopeless, although getting
> rid
> > of neutral current and ground loops can allow the field to fall off more
> > quickly as you move away from the lines. This means interrupting current
> in
> > metal water pipes, disconnecting extra ground connections, gas to
> electric
> > connections. It's good to figure out where current flows in the
> > neighborhood before hring a plumber.
> >
> >
> > On Sat, Jan 1, 2011 at 2:35 AM, ChrisR <vwporscheaudi@...> wrote:
> >
> > >
> > >
> > > Hi Guys! New to the group, and one of the many topics I hope to learn
> more
> > > about is shielding magnetic fields. Im close to the main line to the
> house,
> > > and the panel box in the bedroom. I would like to use some kind of foil
> or
> > > other material to line outside the house wall, and panel to block some
> of
> > > the magnetic entering through the wall. I hope someone has heard about
> this
> > > before. Im getting a 10mg reading or higher sometimes!
> > >
> > > Thanks guys.
> > >
> > >
> > >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>  
>


[Non-text portions of this message have been removed]



------------------------------------

Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/eSens/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/eSens/join
    (Yahoo! ID required)

<*> To change settings via email:
    [hidden email]
    [hidden email]

<*> To unsubscribe from this group, send an email to:
    [hidden email]

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/

Reply | Threaded
Open this post in threaded view
|

Re: Experience with Magnetic Shielding?

ChrisR
Thanks for the responses.  

To add to this matter, I have recently found that before my CATV cable is grounded at the meter tube close to my bedroom, that I have high gauss readings!  I believe this to be my issue, or at least half of it.  The CATV coaxial cable drapes close to my bedroom windows, close than the actual power lines by about 5 feet.  

I have called the cable company and told them my issue.  The last guy was scared to climb on a ladder to install some cables, will see how the pressure increases what happens haha.   I believe there to be some power on the CATV lines... if anything, im getting it re-routed, which is much easier than power feeds.

I have also noticed high readings from the neighbors property.  They have a old style knob and tube from the lines to there house going close by my room.  This is really old style, and seems like a ionizer at this point...

Anywho, thats the update.
Thanks again, and I will try to help my best back in the group!
All the best.

--- In [hidden email], Bill Bruno <wbruno@...> wrote:

>
> The safest advice is to move.
>
> Or for about $5k (maybe much more or less) you might be
> able to get the meter moved to a pole away from the house.
> Then have twisted wires (I think aluminum comes pre-twisted)
> run underground to the panel.  You will still get high readings
> but not as high.  Beware they may insist on upgrading the meter
> to digital which could make things worse rather than better.
>
> I just tried putting some shielding material over my panel.
> The field 10' inside the house got slightly worse!
>
> I don't quite understand your explanation of the box and shingles.
>
> If the power company wires are twisted evenly I don't think there's
> anything they can do to make it better for you, unless there is
> RFI on the lines in which case you can tell them it's harmful interference
> on you MFJ-856 radio and they should try to fix that.
>
> The issue with net current is that all the current coming from
> the power company on the wires should return via the neutral wire.
> Usually it doesn't because it can go back through the ground rod or
> pipes.  It's not obvious whether breaking those connections will
> help you in the shower, but further away it can make a big difference
> (unless the dominant field is from something else, like the lines on the
> street).
>
> Chances are removing all those connections will violate code, but the
> grounding rules seem to be changing a lot.  As long as the neutral and
> ground are bonded in the panel (which is true in the US for the most part)
> you won't notice if there is no earth connection, unless the neutral wire
> breaks some day.  Which you would notice in either case, but might be less
> dangerous with the connections.  I've never encountered such a neutral break
> but they do happen sometimes, so I've read.  But it seems unlikely unless
> there is construction or rewiring being done.
>
>
>
> On Sat, Jan 1, 2011 at 11:54 AM, ChrisR <vwporscheaudi@...> wrote:
>
> >
> >
> > Hi Bill. Thanks for your response. I will look into the silicon steel more,
> > as this may be a little cheaper than all this mu-metal ive been looking at!
> >
> > My issue continued: I have the power "drop-down" coming into my roof and
> > going on the opposite wall of my shower and bedroom. the box is pretty much
> > next to my head when I shower, and the highest readings.
> >
> > I want to put a piece of shield(silicon steel?) in between the back of the
> > panel box, and the shingles on my house. its a small distance, maybe 1", but
> > anything I can pack in that distance is best.
> >
> > Is there a wrap or conduit that is good to wrap around the power lines? (of
> > course with power company approval)
> >
> > thanks.
> >
> > p.s. as far as checking current to ground in the neighborhood, can you
> > elaborate? get a net current flow meter and walk to my neighbors houses
> > putting it around the water/gas/ground lines?
> >
> > would the catv line near the power line amplify the magnetic field?
> >
> >
> > --- In [hidden email] <eSens%40yahoogroups.com>, Bill Bruno
> > <wbruno@> wrote:
> > >
> > > Magnetic shielding tends to be too expensive to use on a whole house.
> > > You can't use aluminum foil, but mu-metal foil will make an improvement.
> > > The most cost effective is silicon steel (magnet steel). It's not a foil,
> > > it is sheet metal. The grain of the metal should align with the field.
> > >
> > > From 10mG you have a long way to go. Even to get a small area down to 2mG
> > > would be a challenge, and ideally you want 0.02 mG or lower.
> > >
> > > If it's coming from a power line it's pretty hopeless, although getting
> > rid
> > > of neutral current and ground loops can allow the field to fall off more
> > > quickly as you move away from the lines. This means interrupting current
> > in
> > > metal water pipes, disconnecting extra ground connections, gas to
> > electric
> > > connections. It's good to figure out where current flows in the
> > > neighborhood before hring a plumber.
> > >
> > >
> > > On Sat, Jan 1, 2011 at 2:35 AM, ChrisR <vwporscheaudi@> wrote:
> > >
> > > >
> > > >
> > > > Hi Guys! New to the group, and one of the many topics I hope to learn
> > more
> > > > about is shielding magnetic fields. Im close to the main line to the
> > house,
> > > > and the panel box in the bedroom. I would like to use some kind of foil
> > or
> > > > other material to line outside the house wall, and panel to block some
> > of
> > > > the magnetic entering through the wall. I hope someone has heard about
> > this
> > > > before. Im getting a 10mg reading or higher sometimes!
> > > >
> > > > Thanks guys.
> > > >
> > > >
> > > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >
> >  
> >
>
>
> [Non-text portions of this message have been removed]
>


Reply | Threaded
Open this post in threaded view
|

Re: Experience with Magnetic Shielding?

evie15422
In reply to this post by ChrisR
Hi, Chris,
 
Are you living in a rental or condo type dwelling?  If not, have you considered changing the entrance of your electric power to another location?  This will not work for every house, but in my house, we had the circuit box, and entrance to it, moved to the far side of a semi-attached garage.  We had the actual meter put on the pole at the street, so now instead of being 3 to 10 feet away when we are sitting in our living room, it is at least 40 feet away.  The circuit box is at least 25 feet away.  Yes, this was pricey--especially since we had to erect a new pole, but you are talking alot of shielding which might or might not work and it is also very pricey.  As I mentioned earlier, this is not a solution which will work for everyone, but it might be something you never even considered. 
 
Just a thought;
Diane

--- On Sat, 1/1/11, ChrisR <[hidden email]> wrote:


From: ChrisR <[hidden email]>
Subject: [eSens] Re: Experience with Magnetic Shielding?
To: [hidden email]
Date: Saturday, January 1, 2011, 1:54 PM


 



Hi Bill. Thanks for your response. I will look into the silicon steel more, as this may be a little cheaper than all this mu-metal ive been looking at!

My issue continued: I have the power "drop-down" coming into my roof and going on the opposite wall of my shower and bedroom. the box is pretty much next to my head when I shower, and the highest readings.

I want to put a piece of shield(silicon steel?) in between the back of the panel box, and the shingles on my house. its a small distance, maybe 1", but anything I can pack in that distance is best.

Is there a wrap or conduit that is good to wrap around the power lines? (of course with power company approval)

thanks.

p.s. as far as checking current to ground in the neighborhood, can you elaborate? get a net current flow meter and walk to my neighbors houses putting it around the water/gas/ground lines?

would the catv line near the power line amplify the magnetic field?

--- In [hidden email], Bill Bruno <wbruno@...> wrote:

>
> Magnetic shielding tends to be too expensive to use on a whole house.
> You can't use aluminum foil, but mu-metal foil will make an improvement.
> The most cost effective is silicon steel (magnet steel). It's not a foil,
> it is sheet metal. The grain of the metal should align with the field.
>
> From 10mG you have a long way to go. Even to get a small area down to 2mG
> would be a challenge, and ideally you want 0.02 mG or lower.
>
> If it's coming from a power line it's pretty hopeless, although getting rid
> of neutral current and ground loops can allow the field to fall off more
> quickly as you move away from the lines. This means interrupting current in
> metal water pipes, disconnecting extra ground connections, gas to electric
> connections. It's good to figure out where current flows in the
> neighborhood before hring a plumber.
>
>
> On Sat, Jan 1, 2011 at 2:35 AM, ChrisR <vwporscheaudi@...> wrote:
>
> >
> >
> > Hi Guys! New to the group, and one of the many topics I hope to learn more
> > about is shielding magnetic fields. Im close to the main line to the house,
> > and the panel box in the bedroom. I would like to use some kind of foil or
> > other material to line outside the house wall, and panel to block some of
> > the magnetic entering through the wall. I hope someone has heard about this
> > before. Im getting a 10mg reading or higher sometimes!
> >
> > Thanks guys.
> >
> >
> >
>
>
> [Non-text portions of this message have been removed]
>









     

[Non-text portions of this message have been removed]

Reply | Threaded
Open this post in threaded view
|

Re: Experience with Magnetic Shielding?

BiBrun
In reply to this post by ChrisR
You should tell them that not only is the knob and tube
terrible safety-wise, it also will cause interference on all
their electronics.  They should upgrade at least to romex,
ideally metal clad or in conduit, twisted.  3-conductor romex
is usually twisted and that would help.

It's usually a good idea for all the wires (cable, electric) to follow
more or less the same path.  That way the AC on the cable will
make a smaller loop.  If it was my house I would disconnect that
ground or put a spark gap or big $4 Zener diode (bi-directional,
12V should be OK, also called transient voltage suppressor TVS).

In which case it's only grounded when lightning hits (unless the
TVS gets burnt away).  It's actually nice to have it grounded
to reduce electric fields, but you want to ground it far away from
you to reduce the magnetic field.   So have the ground wire follow
back where the cable came from and ground it at the property line if
possible.  Or have the cable guy open the jacket and ground it at the
property line.   Or tell him to disconnect the whole thing....


On Sat, Jan 1, 2011 at 10:54 PM, ChrisR <[hidden email]> wrote:

>
>
> Thanks for the responses.
>
> To add to this matter, I have recently found that before my CATV cable is
> grounded at the meter tube close to my bedroom, that I have high gauss
> readings! I believe this to be my issue, or at least half of it. The CATV
> coaxial cable drapes close to my bedroom windows, close than the actual
> power lines by about 5 feet.
>
> I have called the cable company and told them my issue. The last guy was
> scared to climb on a ladder to install some cables, will see how the
> pressure increases what happens haha. I believe there to be some power on
> the CATV lines... if anything, im getting it re-routed, which is much easier
> than power feeds.
>
> I have also noticed high readings from the neighbors property. They have a
> old style knob and tube from the lines to there house going close by my
> room. This is really old style, and seems like a ionizer at this point...
>
> Anywho, thats the update.
> Thanks again, and I will try to help my best back in the group!
> All the best.
>
>
> --- In [hidden email] <eSens%40yahoogroups.com>, Bill Bruno
> <wbruno@...> wrote:
> >
> > The safest advice is to move.
> >
> > Or for about $5k (maybe much more or less) you might be
> > able to get the meter moved to a pole away from the house.
> > Then have twisted wires (I think aluminum comes pre-twisted)
> > run underground to the panel. You will still get high readings
> > but not as high. Beware they may insist on upgrading the meter
> > to digital which could make things worse rather than better.
> >
> > I just tried putting some shielding material over my panel.
> > The field 10' inside the house got slightly worse!
> >
> > I don't quite understand your explanation of the box and shingles.
> >
> > If the power company wires are twisted evenly I don't think there's
> > anything they can do to make it better for you, unless there is
> > RFI on the lines in which case you can tell them it's harmful
> interference
> > on you MFJ-856 radio and they should try to fix that.
> >
> > The issue with net current is that all the current coming from
> > the power company on the wires should return via the neutral wire.
> > Usually it doesn't because it can go back through the ground rod or
> > pipes. It's not obvious whether breaking those connections will
> > help you in the shower, but further away it can make a big difference
> > (unless the dominant field is from something else, like the lines on the
> > street).
> >
> > Chances are removing all those connections will violate code, but the
> > grounding rules seem to be changing a lot. As long as the neutral and
> > ground are bonded in the panel (which is true in the US for the most
> part)
> > you won't notice if there is no earth connection, unless the neutral wire
> > breaks some day. Which you would notice in either case, but might be less
> > dangerous with the connections. I've never encountered such a neutral
> break
> > but they do happen sometimes, so I've read. But it seems unlikely unless
> > there is construction or rewiring being done.
> >
> >
> >
> > On Sat, Jan 1, 2011 at 11:54 AM, ChrisR <vwporscheaudi@...> wrote:
> >
> > >
> > >
> > > Hi Bill. Thanks for your response. I will look into the silicon steel
> more,
> > > as this may be a little cheaper than all this mu-metal ive been looking
> at!
> > >
> > > My issue continued: I have the power "drop-down" coming into my roof
> and
> > > going on the opposite wall of my shower and bedroom. the box is pretty
> much
> > > next to my head when I shower, and the highest readings.
> > >
> > > I want to put a piece of shield(silicon steel?) in between the back of
> the
> > > panel box, and the shingles on my house. its a small distance, maybe
> 1", but
> > > anything I can pack in that distance is best.
> > >
> > > Is there a wrap or conduit that is good to wrap around the power lines?
> (of
> > > course with power company approval)
> > >
> > > thanks.
> > >
> > > p.s. as far as checking current to ground in the neighborhood, can you
> > > elaborate? get a net current flow meter and walk to my neighbors houses
> > > putting it around the water/gas/ground lines?
> > >
> > > would the catv line near the power line amplify the magnetic field?
> > >
> > >
> > > --- In [hidden email] <eSens%40yahoogroups.com> <eSens%
> 40yahoogroups.com>, Bill Bruno
>
> > > <wbruno@> wrote:
> > > >
> > > > Magnetic shielding tends to be too expensive to use on a whole house.
> > > > You can't use aluminum foil, but mu-metal foil will make an
> improvement.
> > > > The most cost effective is silicon steel (magnet steel). It's not a
> foil,
> > > > it is sheet metal. The grain of the metal should align with the
> field.
> > > >
> > > > From 10mG you have a long way to go. Even to get a small area down to
> 2mG
> > > > would be a challenge, and ideally you want 0.02 mG or lower.
> > > >
> > > > If it's coming from a power line it's pretty hopeless, although
> getting
> > > rid
> > > > of neutral current and ground loops can allow the field to fall off
> more
> > > > quickly as you move away from the lines. This means interrupting
> current
> > > in
> > > > metal water pipes, disconnecting extra ground connections, gas to
> > > electric
> > > > connections. It's good to figure out where current flows in the
> > > > neighborhood before hring a plumber.
> > > >
> > > >
> > > > On Sat, Jan 1, 2011 at 2:35 AM, ChrisR <vwporscheaudi@> wrote:
> > > >
> > > > >
> > > > >
> > > > > Hi Guys! New to the group, and one of the many topics I hope to
> learn
> > > more
> > > > > about is shielding magnetic fields. Im close to the main line to
> the
> > > house,
> > > > > and the panel box in the bedroom. I would like to use some kind of
> foil
> > > or
> > > > > other material to line outside the house wall, and panel to block
> some
> > > of
> > > > > the magnetic entering through the wall. I hope someone has heard
> about
> > > this
> > > > > before. Im getting a 10mg reading or higher sometimes!
> > > > >
> > > > > Thanks guys.
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > > [Non-text portions of this message have been removed]
> > > >
> > >
> > >
> > >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>  
>


[Non-text portions of this message have been removed]



------------------------------------

Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/eSens/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/eSens/join
    (Yahoo! ID required)

<*> To change settings via email:
    [hidden email]
    [hidden email]

<*> To unsubscribe from this group, send an email to:
    [hidden email]

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/

Reply | Threaded
Open this post in threaded view
|

Re: Experience with Magnetic Shielding?

ChrisR
I had a cable guy come out to check it out. He was overwhelmed, but will return next week to do some changes with another helper.  Quite understanding at least at this point...

Bruno, it looks like I have a couple options:
1. move ground out to property line, and ground shielded catv line before coming into my area.
2. install a spark gap?
3. install a transient voltage surpressor?

the last two i researched and still couldnt find much info on the stuff.  is it similar to a ground loop isolator?  I read about those on one website breifly...

Thanks!

--- In [hidden email], Bill Bruno <wbruno@...> wrote:

>
> You should tell them that not only is the knob and tube
> terrible safety-wise, it also will cause interference on all
> their electronics.  They should upgrade at least to romex,
> ideally metal clad or in conduit, twisted.  3-conductor romex
> is usually twisted and that would help.
>
> It's usually a good idea for all the wires (cable, electric) to follow
> more or less the same path.  That way the AC on the cable will
> make a smaller loop.  If it was my house I would disconnect that
> ground or put a spark gap or big $4 Zener diode (bi-directional,
> 12V should be OK, also called transient voltage suppressor TVS).
>
> In which case it's only grounded when lightning hits (unless the
> TVS gets burnt away).  It's actually nice to have it grounded
> to reduce electric fields, but you want to ground it far away from
> you to reduce the magnetic field.   So have the ground wire follow
> back where the cable came from and ground it at the property line if
> possible.  Or have the cable guy open the jacket and ground it at the
> property line.   Or tell him to disconnect the whole thing....
>
>
> On Sat, Jan 1, 2011 at 10:54 PM, ChrisR <vwporscheaudi@...> wrote:
>
> >
> >
> > Thanks for the responses.
> >
> > To add to this matter, I have recently found that before my CATV cable is
> > grounded at the meter tube close to my bedroom, that I have high gauss
> > readings! I believe this to be my issue, or at least half of it. The CATV
> > coaxial cable drapes close to my bedroom windows, close than the actual
> > power lines by about 5 feet.
> >
> > I have called the cable company and told them my issue. The last guy was
> > scared to climb on a ladder to install some cables, will see how the
> > pressure increases what happens haha. I believe there to be some power on
> > the CATV lines... if anything, im getting it re-routed, which is much easier
> > than power feeds.
> >
> > I have also noticed high readings from the neighbors property. They have a
> > old style knob and tube from the lines to there house going close by my
> > room. This is really old style, and seems like a ionizer at this point...
> >
> > Anywho, thats the update.
> > Thanks again, and I will try to help my best back in the group!
> > All the best.
> >
> >
> > --- In [hidden email] <eSens%40yahoogroups.com>, Bill Bruno
> > <wbruno@> wrote:
> > >
> > > The safest advice is to move.
> > >
> > > Or for about $5k (maybe much more or less) you might be
> > > able to get the meter moved to a pole away from the house.
> > > Then have twisted wires (I think aluminum comes pre-twisted)
> > > run underground to the panel. You will still get high readings
> > > but not as high. Beware they may insist on upgrading the meter
> > > to digital which could make things worse rather than better.
> > >
> > > I just tried putting some shielding material over my panel.
> > > The field 10' inside the house got slightly worse!
> > >
> > > I don't quite understand your explanation of the box and shingles.
> > >
> > > If the power company wires are twisted evenly I don't think there's
> > > anything they can do to make it better for you, unless there is
> > > RFI on the lines in which case you can tell them it's harmful
> > interference
> > > on you MFJ-856 radio and they should try to fix that.
> > >
> > > The issue with net current is that all the current coming from
> > > the power company on the wires should return via the neutral wire.
> > > Usually it doesn't because it can go back through the ground rod or
> > > pipes. It's not obvious whether breaking those connections will
> > > help you in the shower, but further away it can make a big difference
> > > (unless the dominant field is from something else, like the lines on the
> > > street).
> > >
> > > Chances are removing all those connections will violate code, but the
> > > grounding rules seem to be changing a lot. As long as the neutral and
> > > ground are bonded in the panel (which is true in the US for the most
> > part)
> > > you won't notice if there is no earth connection, unless the neutral wire
> > > breaks some day. Which you would notice in either case, but might be less
> > > dangerous with the connections. I've never encountered such a neutral
> > break
> > > but they do happen sometimes, so I've read. But it seems unlikely unless
> > > there is construction or rewiring being done.
> > >
> > >
> > >
> > > On Sat, Jan 1, 2011 at 11:54 AM, ChrisR <vwporscheaudi@> wrote:
> > >
> > > >
> > > >
> > > > Hi Bill. Thanks for your response. I will look into the silicon steel
> > more,
> > > > as this may be a little cheaper than all this mu-metal ive been looking
> > at!
> > > >
> > > > My issue continued: I have the power "drop-down" coming into my roof
> > and
> > > > going on the opposite wall of my shower and bedroom. the box is pretty
> > much
> > > > next to my head when I shower, and the highest readings.
> > > >
> > > > I want to put a piece of shield(silicon steel?) in between the back of
> > the
> > > > panel box, and the shingles on my house. its a small distance, maybe
> > 1", but
> > > > anything I can pack in that distance is best.
> > > >
> > > > Is there a wrap or conduit that is good to wrap around the power lines?
> > (of
> > > > course with power company approval)
> > > >
> > > > thanks.
> > > >
> > > > p.s. as far as checking current to ground in the neighborhood, can you
> > > > elaborate? get a net current flow meter and walk to my neighbors houses
> > > > putting it around the water/gas/ground lines?
> > > >
> > > > would the catv line near the power line amplify the magnetic field?
> > > >
> > > >
> > > > --- In [hidden email] <eSens%40yahoogroups.com> <eSens%
> > 40yahoogroups.com>, Bill Bruno
> >
> > > > <wbruno@> wrote:
> > > > >
> > > > > Magnetic shielding tends to be too expensive to use on a whole house.
> > > > > You can't use aluminum foil, but mu-metal foil will make an
> > improvement.
> > > > > The most cost effective is silicon steel (magnet steel). It's not a
> > foil,
> > > > > it is sheet metal. The grain of the metal should align with the
> > field.
> > > > >
> > > > > From 10mG you have a long way to go. Even to get a small area down to
> > 2mG
> > > > > would be a challenge, and ideally you want 0.02 mG or lower.
> > > > >
> > > > > If it's coming from a power line it's pretty hopeless, although
> > getting
> > > > rid
> > > > > of neutral current and ground loops can allow the field to fall off
> > more
> > > > > quickly as you move away from the lines. This means interrupting
> > current
> > > > in
> > > > > metal water pipes, disconnecting extra ground connections, gas to
> > > > electric
> > > > > connections. It's good to figure out where current flows in the
> > > > > neighborhood before hring a plumber.
> > > > >
> > > > >
> > > > > On Sat, Jan 1, 2011 at 2:35 AM, ChrisR <vwporscheaudi@> wrote:
> > > > >
> > > > > >
> > > > > >
> > > > > > Hi Guys! New to the group, and one of the many topics I hope to
> > learn
> > > > more
> > > > > > about is shielding magnetic fields. Im close to the main line to
> > the
> > > > house,
> > > > > > and the panel box in the bedroom. I would like to use some kind of
> > foil
> > > > or
> > > > > > other material to line outside the house wall, and panel to block
> > some
> > > > of
> > > > > > the magnetic entering through the wall. I hope someone has heard
> > about
> > > > this
> > > > > > before. Im getting a 10mg reading or higher sometimes!
> > > > > >
> > > > > > Thanks guys.
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > > > [Non-text portions of this message have been removed]
> > > > >
> > > >
> > > >
> > > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >
> >  
> >
>
>
> [Non-text portions of this message have been removed]
>