[mythtv-users] Poor electrical ground (older apt.) + Nvidia tv out = poor tv quaility

Kyle Rose krose+mythtv at krose.org
Fri Oct 8 20:03:59 UTC 2004


Wayne Steenburg <w.steenburg at myactv.net> writes:

> I live in an older
> building which doesn't have grounded recepticles so I had connected the
> ground screw to the neutral wire ( They eventually go to the same place
> in the electrical panel, so it's usually better then nothing.)

Aaaahhh!!  You are putting users in danger doing this by giving them
the false impression that there is a separate path to ground when in
fact there is not.  The safe thing to do here is described by the NEC:
install a GFCI, leave the ground unplugged, and label it "No Equipment
Ground."

> in the message I ran a new circuit to my entertainment center.  Not only
> did the humming go away, but the tv-out is crystal clear.

This is definitely the right thing to do.

I know tihs is off-topic, but in case anyone decides to do what you
did above (Bad! Bad!): an acceptably safe solution (with the standard
disclaimer that I am *not* an electrician and will not be held
accountable should you disable yourself or a loved one by following my
advice) is to hook the ground screw up to a pipe (baseboard heating,
cold water, etc.) with a grounding clamp and then connect that
somewhere on the same system to the breaker panel ground, also with a
grounding clamp.  A ground wire doesn't ever need to carry line
current for any long period of time, but you need to make sure the
impedance is low enough that a breaker will trip if the circuit ground
faults.

Still, running a new circuit is the much, *much* better solution, if
possible.

Cheers,
Kyle


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