Connect with us

Can anyone help me build my own surge protector for a coaxile cable tv connector?

Discussion in 'Electronic Design' started by CoreyWhite, Feb 12, 2007.

  1. CoreyWhite

    CoreyWhite Guest

    My cable blew out my high-definition television, and it won't turn on
    any more. Surges come through the cable lines, and without a fuse to
    protect against abnormal voltage, I'm sure it will happen again. I
    didn't have any problems until after I had a cable guy install digital
    cable, road runner, and digital phone service to my house. And he
    said he didn't have time to ground the cabling.

    Any ideas how I could test to find out what sort of fuse I would need?
     
  2. legg

    legg Guest

    You could probably sue.

    Otherwise install the grounding surge protection where the cable
    enters the biulding. It's a fairly simple and cheap device you should
    find in any CB, television or radio spares supply - probably in the
    dustiest section of the store.

    It's basically an aluminum block - a cable clamp with a small spike in
    it to penetrate the outer sheath of the cable only, and a long wire
    that you are expected to attach to a rod in the immediate ground area
    or to a nearby standing metal pipe.

    RL
     
  3. craigm

    craigm Guest


    Why not buy something like this?
    http://www.cablestogo.com/product.asp?cat_id=2403&sku=41035
     
  4. GPG

    GPG Guest

  5. You need a surge protector. Just by chance, some spamming moron just
    posted an advertisement for such equipment in this very
    newsgroup............

    .....Oh. Sorry.
     
  6. Tam/WB2TT

    Tam/WB2TT Guest

    Fuses won't work, they are way too slow. A surge protector on both the AC
    line and the coax might. Unless your cable box fried, your power company
    seems like a more likely culprit.

    Tam
     
  7. w_tom

    w_tom Guest

    Craigm displayed what is required on every cable where that cable
    enters the building:
    http://www.cablestogo.com/product.asp?cat_id=2403&sku=41035

    Either you don't have it or it is not connected to the same earth
    ground also used by AC electric and telephone. Even National
    Electrical Code (NEC) says that connection must exist.

    You don't need a surge protector. Surge protectors are only devices
    to connect to earthing. Earthing is the protection. If you have:
    http://www.cablestogo.com/product.asp?cat_id=2403&sku=41035
    properly connected to that earth ground, then your cable is already
    earthed.

    Meanwhile, AC electric does require a 'whole house' protector. No
    effective protector has been seen in Sears, Best Buy, Radio Shack,
    Staples, Circuit City, K-mart, or your grocery store. Those
    protectors also do not have the dedicated earthing wire. An effective
    'whole house' protector is sold in Lowes, Home Depot, and electrical
    supply houses. And, of course, your earthing must meet and exceed
    post 1990 NEC earthing requirements.

    More numbers. Fuses take milliseconds to trip. Surges are done in
    microseconds. You could have 300 consecutive surges before a fuse
    even considers blowing. Meanwhile, you obviously don't have something
    on your cable equivalent to
    http://www.cablestogo.com/product.asp?cat_id=2403&sku=41035
    Thats maybe $2 at Lowes, Radio Shack, Home Depot, or anyplace else
    that sells cable connecting materials. An earthed ground block is
    that routine, that essential, and obviously not on your service.

    Anyone with no technical knowledge can follow that earthing wire. A
    'less than 10 foot' wire goes from each: breaker box, from telephone
    NID, and from cable ... all to the same dedicated earthing rod. Not
    to a water faucet. Not to a cold water pipe. Not to dirt in a flower
    box. Earthing wire must go to a dedicated ground rod that is also
    used by all other utilities. Otherwise your wiring does not even meet
    1990 NEC requirements. And who is responsible for providing that
    earthing? You.

    Service man has installed in violation of NEC if he did not install
    a 'less than 10 foot' connection to that earthing also used by AC
    electric. No way around those code requirements. Neither fuse nor
    surge protector on cable is a solution.
     
  8. Jim Thompson

    Jim Thompson Guest

    Sue the cable company for an inadequate installation.

    ...Jim Thompson
     
  9. bud--

    bud-- Guest

    Regarding Corey White - I follow the alt.magic newsgroup where the
    following has been posted several times:
    http://groups.google.com/group/alt....4d646b0f3d5?lnk=st&q=&rnum=3#2b41a4d646b0f3d5
    or, more manageably
    http://tinyurl.com/ywndle
    see message #8
    The original post may not be a 'real' problem.

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

    The best information I have seen on surges and surge protection is
    available from the
    IEEE at:
    http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
    And from the NIST at
    http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf

    Both guides were intended for wide distribution to the general public
    to explain surges and how to protect against them. The IEEE guide was
    targeted at people who have some technical background and will
    probably be of more interest to people on this newsgroup.

    Obviously should have been installed.

    w_ is saying plug-in surge suppressors don't work. But both the IEEE
    and NIST guide say they are effective. Plug-in suppressors, as
    described in the IEEE guide, work by CLAMPING the voltage on all wires
    to the common ground at the suppressor. They do not work primarily by
    earthing.

    Earthing the CATV ground block does not necessarily prevent problems.
    If the ground block and power system earthing are not connected in a
    "single point ground" voltages between CATV and power can damage
    equipment as illustrated in the IEEE guide, starting guide page 31.
    (The same can happen with phone wires.) The guide also illustrates how
    a plug-in surge suppressor can protect equipment where a single point
    ground is not present. As above, the voltage on all wires (signal and
    ground) are clamped to the common ground at the suppressor.

    I agree fuses are way too slow.

    Normal practice is to connect a short earthing wire from CATV and
    phone to the earthing wire from the power service close to the power
    service. The longer any of these interconnecting wires are when
    forming a single point ground the more likely there will be damaging
    voltages between systems if a surge hits.

    ??? The installer is responsible for providing earthing.

    If the cable entry point is distant from the electric service it may
    not be possible to have a short connection. For 1 & 2 family dwellings
    the NEC says 20 feet (with an exception) - not 10 - and the actual
    distance to the earthing wire at the power service can be much longer
    than that. If it is not possible to get a short connection, the cable
    can run adjacent to the power service, a second ground block
    installed, and cable distributed from there. The same with phone. Or
    as in the example in the IEEE guide, protection can be provided with a
    plug-in surge protector.
     
  10. bud--

    bud-- Guest

    Regarding Corey White - I follow the alt.magic newsgroup where the
    following has been posted several times:
    http://groups.google.com/group/alt....4d646b0f3d5?lnk=st&q=&rnum=3#2b41a4d646b0f3d5
    or, more manageably
    http://tinyurl.com/ywndle
    see message #8
    The original post may not be a 'real' problem.

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

    The best information I have seen on surges and surge protection is
    available from the
    IEEE at:
    http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
    And from the NIST at
    http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf

    Both guides were intended for wide distribution to the general public
    to explain surges and how to protect against them. The IEEE guide was
    targeted at people who have some technical background and will
    probably be of more interest to people on this newsgroup.

    Obviously should have been installed.

    w_ is saying plug-in surge suppressors don't work. But both the IEEE
    and NIST guide say they are effective. Plug-in suppressors, as
    described in the IEEE guide, work by CLAMPING the voltage on all wires
    to the common ground at the suppressor. They do not work primarily by
    earthing.

    Earthing the CATV ground block does not necessarily prevent problems.
    If the ground block and power system earthing are not connected in a
    "single point ground" voltages between CATV and power can damage
    equipment as illustrated in the IEEE guide, starting guide page 31.
    (The same can happen with phone wires.) The guide also illustrates how
    a plug-in surge suppressor can protect equipment where a single point
    ground is not present. As above, the voltage on all wires (signal and
    ground) are clamped to the common ground at the suppressor.

    I agree fuses are way too slow.

    Normal practice is to connect a short earthing wire from CATV and
    phone to the earthing wire from the power service close to the power
    service. The longer any of these interconnecting wires are when
    forming a single point ground the more likely there will be damaging
    voltages between systems if a surge hits.

    ??? The installer is responsible for providing earthing.

    If the cable entry point is distant from the electric service it may
    not be possible to have a short connection. For 1 & 2 family dwellings
    the NEC says 20 feet (with an exception) - not 10 - and the actual
    distance to the earthing wire at the power service can be much longer
    than that. If it is not possible to get a short connection, the cable
    can run adjacent to the power service, a second ground block
    installed, and cable distributed from there. The same with phone. Or
    as in the example in the IEEE guide, protection can be provided with a
    plug-in surge protector.
     
  11. Kisai

    Kisai Guest


    The purpose of a circuit box fuse isn't to protect the equipment in
    your house, but to stop the
    house wiring from overheating and starting a fire.

    There's a number of things that can have gone wrong with your "new"
    HDTV, from a power surge to a faulty
    power supply. If it's "new", then it should be under warranty.

    However, most likely, the fault is that your HDTV doesn't actually
    exist. Case in point:

    http://groups.google.com/group/alt....=CoreyWhite+32"&rnum=1&hl=en#950c7aa9e0d5eb20

    In this thread, you report that your HDTV is actually 32". Did it
    shrink 5" from the 27" size that you recently reported?
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-