Re: Wierd Ground Problem?

Yes, the cable incoming from dish must make a connection to
earth that is also the earth ground of every other incoming
utility wire. This 'single point earth ground' is required by
code for human safety AND also performed for reason not in the
code - transistor safety. This is also part of a system that
should make hum and static irrelevant.

The dish should be earthed directly. Also the incoming
cable from dishes should be connected to the single point
earth ground for reasons stated above. Since cable ground
block must connect to single point earth ground (which should
be at least an existing 8 foot ground rod), then two ways to
accomplish it. One is to reroute the incoming RG-6 so that it
enters the building and is earthed at the single point
earthing. Or expand the single point earthing using a buried,
bare copper wire (of size required by code) to include that
existing 4 foot earth ground rod. The second, if practical,
enhances what would otherwise be a minimally acceptable earth
ground.

That 6 AWG wire 50 feet long to water pipe is no longer
considered earth ground per post-1990 code. Again, that is why
the 'earthed at far end' antenna example was cited. That 50
foot wire removes electricity from water pipes as required by
code. But the earth ground must be, typically, an eight foot
ground rod located at the service entrance (ie outside and
adjacent to breaker box). Earthing connection that must be
many times shorter than 50 feet. The code is quite specific:
Article 250.52(D)(2)
> Supplemental Electrode Required. A metal underground water
> pipe shall be supplemented by an additional electrode of the
> type specified in 250.52(A)(2) through (A)(7).

The eight foot ground rod is one of those acceptable earth
grounds in sections (A)(2) through (A)(7). Of course multiple
ground rods spaced per code requirements makes an even better
earth ground.

All other incoming utilities (telephone, cable) must connect
to that ground rod by less than 20 feet of wire. And then
more parameters, so that earth ground also provides transistor
safety. Every wire connecting to that earth ground must not
be bundled with other non-earth wires, must have no sharp
bends, no splices, must not connect to other earthing wires
until all meet at the ground rod, must be as short as possible
and 'less than 10 feet', and must not pass inside conduit or
other metallic item. A buried ground wire connecting to that
four foot rod would make that other earth ground part of the
single point earth ground AND supplement the effectiveness of
earthing.

For example, the #6 AWG wire from breaker box to earth
ground rod is better routed through foundation at least six
inches about outside soil rather than up over foundation,
through 2x10 wood, and back down to earth ground. Distance of
and routing that earthing wire away from other wires is for
transistor safety.

Connecting any wire to water pipes or faucet to establish a
ground is wrong - long time not acceptable. A simplified
version of the rule. Wire is connected to pipes only to
remove electricity from those pipes. That is what the 50 foot
wire from pipe to breaker box does - remove electricity -
especially to trip a circuit breaker if necessary.

Furthermore, the proposed 30 foot connection is even longer
because faucet's water pipes add more distance, solder joints
make that distance electrically longer, and sharp bends make
it electrically further. Again, return to that example of a
radio antenna earthed at the far end. Earthing did not affect
a radio signal because wire distance is critical for some
types of electricity. That 30 feet plus to earth ground
violates National Electrical Code (NEC) requirements AND so
long as to be not earthed from a perspective of transistor
safety.

And you thought grounding was so simple. We are discussing
earth ground; have neither discussed breaker box safety ground
nor that UPS ground. Those are other grounds. And then there
is bonding to the water pipe. Just another type of ground. A
safety ground which is why code uses the word 'bonding'; not
earthing.

A figure from a utility demonstrates the bad, good, and
least ugly ways of accomplishing a single point earth ground:
http://www.cinergy.com/surge/ttip08.htm

Notice how all this grounding forms a hierarchy. Earth
ground in turn meets many other grounds at a common point.
Interconnection grounds at the same 'level' can cause other
problems such as ground loops and hum.

Aluminum wire takes special consideration. Do not connect a
copper item to an aluminum wire. Special connectors are
required when aluminum connects to copper. The dish ground
wire, whatever it is, should make a shortest path from the
dish to earth ground.

Still this is only to meet code, protect humans, and protect
transistors. We have not yet addressed ground loops that
would cause hum.

Lets make that Belkin UPS to local single point ground (not
to be confuse with a single point earth ground or the single
point safety ground that is neutral bar inside breaker box).
Everything connected to audio amplifier (satellite receiver,
PVR) connects to same ground provided by the Belkin. IOW
there is no other incoming cable from any other electronics
that also connected to a household ground anywhere else?

For example, two receivers connected to two different
household grounds. Yes, both connect back to the same breaker
box. But that is long wire. The household ground in the
entertainment room remains different from the ground in
kitchen and from ground in basement. Again, remember that
radio antenna earthed at its far end.

If two different receivers are electrically grounded via
cables to the same dish, now we have a ground loop. That
ground loop may or may not create hum. The single point
ground for equipment common to the Belkin must never connect
to the equipment common of satellite receiver in the
basement. Those grounds must remain separate until both meet
at the breaker box ground. Again, that hierarchy. Otherwise,
a ground loop exists and may create hum.

Electricity at one end of a wire is not same as electricity
at the other end of same wire. Which is why to take care
about single point grounding of equipment AND then single
point grounding all those single point grounds to a building
wide single point ground such as the breaker box. Even water
pipes make a separate connection to that single point breaker
box ground. And that breaker box ground, in turn, connects
where all other earth grounds connect - at a single point
earth ground.

It is quite possible that once you get all satellite cable
grounds directly connected to same earth ground, then single
point earthing eliminates the hum. We will not know until
that single point earth ground is created. IOW start and
correct at the single point ground that is for every ground in
the building - earth ground. And then we move down the chain
of grounds making sure that each next level ground (breaker
box ground, wall receptacle ground, etc) only connects to a
higher level single point ground. Single point ground at
each level for numerous reasons including hum created by
ground loops.

There exists so much in this post that you should read it
multiple times. Welcome to the artistic side of grounding.

cindyanello@xxxxxxxxxxx wrote:
> To clarify - the two satellite dishs and associated cables are
> currently grounded with a Radio Shack 4' copper grounding rod driven 4'
> into the ground - right underneath the satellite dishes. The satellite
> cables run through a set of cable grounding blocks (which are connected
> to the grounding rod). Those grounding blocks are located under the
> roof eaves 5' away from the cable entry point to the home.
>
> All the inside A/V equipment (satellite receiver, PVR, audio amplifier)
> are connected to a Belkin UPS. The UPS in turn is plugged into a wall
> electrical outlet that has a ground to the house circuit panel.
>
> ok - So if I get this right - I need to interconnect the house
> electrical ground to the existing 4' deep copper ground rod system I
> have in place for the satellite dish and RJ6 cable.
>
> That way - if lightening hits the dish - it (may) decide to run to
> ground using the 4' deep ground rod right below the dish. If static
> builds up on the dish - it can drain off either through the 4' deep rod
> or to the house electrical ground. ... and the hum should go away.
>
> By the way - the hum came back recently & we tried unscrewing and
> re-connecting the Co-ax connectors & it did not go away. We ended up
> connecting the downstairs PVR to another satellite lead (we have 2
> dishes on the roof with 2 cable leads each) & that fixed it.... so far
> anyway.
>
> To do the ground interconnection you suggest bare copper ground wire.
> I'm guessing that is to ensure good conductivity and the better
> capacity of that wire to take a lightening hit? If that is the case -
> should I not also replace the existing aluminum ground wire from the
> copper ground rod running up to the dishes?
>
> As an aside - I wonder why they even sell the aluminum grounding wire
> if it is not up to the task. One thought is that it is meant for
> static discharge only & not for lightening hits.
>
> I would run the copper wire around the house up to an outside copper
> water tap & use a bonding clamp to attach it to the copper water pipe.
> Total run distance is about 30 feet.
>
> I was planning on mounting it just under the house eavestroughs - or
> does it have to go under the ground?
>
> The existing house electrical ground wire is a 6 AWG bare copper wire
> that runs from our power panel in the finished basement over to where
> the copper water pipe enters the house foundation. Total run distance
> for this grounding wire is about 50 feet.
.

Relevant Pages

  • Re: Lightning and computer?
    ... Does every incoming utility wire make a 'less than 10 ... That earth ground rod means nothing about earthing the ... the appliance internal protection saved those appliances. ... some appliances make a better connection to earth ...
    (microsoft.public.windowsxp.hardware)
  • Re: belkin power conditioner for my Samsung LCD - is it worth it???
    ... Appreciate the characteristics of electricity. ... Connect a long wire to that radio and earth that far end. ... Why is that earth ground far down the wire ... One of the best earthing electrodes is rebar inside concrete ...
    (alt.tv.tech.hdtv)
  • Re: Repairing Lightning Damaged Tvs
    ... > Establish the single point earth ground. ... > be a buried bare 4 AWG ground wire that interconnects AC ... > not connect to any other earthing wire until they all meet at ... > protector must connect from each wire to that bus bar. ...
    (sci.electronics.repair)
  • AR-XA turntable cable question
    ... and was going to use a gold RCA jack ... wire, which surrounded the signal wire, but was outside the insulation ... connection, which goes to the pin, and a place for the ground ... or is this how turntable cables work? ...
    (rec.audio.tech)
  • Re: USB Headphones hack - Soldering a 3.5mm plug instead of the headphones
    ... The white wire from the cable is going to the tip, ... Do audio stereo cables normally have ... Your cable will have a ground connection, ...
    (rec.audio.tech)