[mythtv-users] OT: Wiring a new construction home for A/V, Ethernet, etc

Allen Edwards allen.p.edwards at gmail.com
Tue Dec 2 19:10:52 UTC 2008

On Tue, Dec 2, 2008 at 8:49 AM, Matt S. <skd5aner at gmail.com> wrote:
> On Tue, Dec 2, 2008 at 12:52 AM, Allen Edwards
> <allen.p.edwards at gmail.com> wrote:
>> You got a ton of great advice.
> You aren't kidding!  Thanks a ton everyone.  I've got a ton of work
> ahead of me, and this will only help me hone my focus and go down the
> right path.
> Any thoughts on if I should run my own AC wire as well?  One person
> mentioned that, in addition to all of the A/V stuff, networking, etc
> stuff I should also home run all the electrical stuff to a single
> closet as well to futureproof for home automation reasons.  I hadn't
> planned on touching any of the "hot" stuff like outlets, switches,
> etc...I was going to leave that up to the qualified electrician.  But,
> is this something I should either do myself or ask my electrician to
> do for me?
> Thanks!
> Matt

I don't think there is much advantage to doing anything special with
the electrical with a couple of exceptions.  You can do it yourself,
let the contractor do it, or like I did help the contractor.

OK, now the two exceptions.  If you are running a projector, you want
that to be the same circuit as the feed for the other AV equipment.  I
ended up running an AC line from my projector through the ceiling to
the wall behind the AV stuff.  If you are not careful, you can get
60Hz bands moving slowly through your picture.  Actually they are not
60Hz but the beat note between the refresh rate and the line frequency
so it is a slow roll.  Keep everything on the same circuit to help
prevent that.

The other issue is grounds.  You want everything grounded to the same
reference point. This goes for the TV antenna, as well as all the
outlet boxes.  This helps prevent audio hum.  There are two issues
with grounding.  1 is that you need a real ground for safety reasons.
That is usually a 8 foot rod hammered into the ground.  2 is that from
an AV standpoint you can pick any single point as a ground reference
but if you pick two, you will get hum.  Given these two points, it is
obvious that the ground rod needs to be the reference point for the AV
rack as well.  That probably won't be a problem, unless you start to
ground something like a Tv antenna to a water pipe.  Just remember
that you want a single ground and you should be OK.

In summary, I would not home run all my outlets unless you are
thinking of having some exotic home automation system.  Personally, I
like flipping actual switches with the exception of one outlet that I
can control from my remote.  Even then, I usually don't use it.  I
would make a dedicated run from a projector location to the AV
equipment so that they don't end up on different circuits.  Finally, I
would make sure that everything that needs to be grounded is grounded
back to the ground rod and not to a water pipe.  And I would ground
the the TV Antenna as well.  If you have satellite, make sure that is
also grounded to that same reference.  You can use coax inline ground
blocks for that but again ground them back to the ground rod.  You can
use a long green wire back to your power drop box to do that.

One final point.  I mounted a 2 inch pips, about 5 feet of it, in my
roof.  It just goes into the attic and is attached securely to the
structure.  I mount my TV antennas on a mast connected to that pipe
and feed the coax wires through the pipe into the attic where my
preamp and all the splitters and distribution are.  It is easy to do
before you build and a pain to do later.  You have to prevent rain
from going down the pipe some way but that should not be difficult as
there are many ways to do that. Oh, you will  need 110 in the attic
for the amplifiers.


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