Two physical grounds??

With all due respect Gs556 should not be giving electrical advice.

"The solution is easy provided you have a metal outlet box. Simply buy a 3-pronged outlet and a package of green ground wires (pre-looped, and with green screws, called 'Equipment Bonding Jumpers'). Remove one of the old two-prongers where you want to install the PC. Install the new grounded outlet to the white/black wires and install the green ground wire to the ground screw of the outlet. At the other end of the green ground wire, screw it to the metal box with the green ground screw. Push the wires back in the box and attach the outlet to the box. You now have a grounded outlet."

No… you now have an ungrounded circuit terminating to a grounded outlet. The exact same as a two wire ungrounded outlets but now not compliant with the National Electrical Code or most International Codes.
T. J.

Try running a #14 awg to the outlet that your power conditioner is using, to a cold water pipe and clamp off to that.
07-07-11: Tjtrout20

Tjtrout20,

No longer an NEC approved method. Not since 1996 I believe. Too many plumbers were getting shocked or electrocuted.
>>>>>>>>>>>>>>>

This dedicated ground rod for the line conditioner will be about 16 feet away from the ground rod for the electrical wiring for my house.
07-07-11: Tiofelon

Tiofelon,

The dedicated ground rod is a bad idea as others have pointed out. Will not meet NEC code either.....

What NEC will allow for old 2 wire ungrounded receptacle/ branch circuit is to install a new equipment ground wire and connect it to the existing main electrical grounding system, (Grounding Electrode System), of the house.

Look at running a ground wire along the exterior of the house and connect it to the ground wire that comes from the house to the existing ground rod. Use an approved wire connector such as a split bolt. DO NOT cut the main ground wire that runs to the existing ground rod......

You might also be able to run the new ground wire back into the house and connect it to the ground bar you spoke of in a later post.

Wire must be protected from physical damage. Support often.
If it were me I would use a solid #10 awg copper wire.

It would really be best to hire a licensed electrician to do the job......

Method for grounding a non grounded receptacle/branch circuit.
NEC 2008 250.130 (C)

Local code (AHJ) has the final say.

Tjtrout20,

In Gs5556 defense he may live in an area were all branch circuits must be installed in conduit. I believe Chicago as well as New York City being two that come to mind. He may have just had a brain fart and forgot not everywhere in the US require branch circuits must be installed in metallic conduit.
Jim

Jea48,
Check this from the 2011 NEC. 250.130(c)1
250.130 (C)
(C) Non grounding Receptacle Replacement or Branch
Circuit Extensions. The equipment grounding conductor
of a grounding-type receptacle or a branch-circuit extension
shall be permitted to be connected to any of the following:
(1) Any accessible point on the grounding electrode system
as described in 250.50
(2) Any accessible point on the grounding electrode conductor
(3) The equipment grounding terminal bar within the enclosure
where the branch circuit for the receptacle or
branch circuit originates
(4) For grounded systems, the grounded service conductor
within the service equipment enclosure
(5) For ungrounded systems, the grounding terminal bar
within the service equipment enclosure
The cold water pipe is part of the Grounding Electrode System. The key word is System, which includes the cold water pipe. Check 250.50 for description of GES.
This is discussed in length on Mike Holts web site.
As far as the correct size of the equipment grounding conductor for 15amp circuits #14awg copper or 20amp circuits #12awg as per 250.122 2011 NEC but nothing wrong with #10 also.
Did not mean to slam GS5556 but a blanket statement like that can get people hurt. Peace T. J.

I think the take-away here is that for hi-current electrical issues and advice, hire a PRO. someone familiar with NEC and any local issues.