Safe to "lift ground" on projector? (1 Viewer)

[Jim A. Banville]

After hooking up my new Panasonic XP30 DVD player to both my 53" RPTV and my Z1, I got horizontal rolling lines. They went away after unhooking the XP30 from the RPTV, but I want to be able to use it with either my projector and TV. I currently "lift the ground" on my subwoofer's three prong plug using a "cheater plug" to alleviate a ground "hum". It occurred to me to try it on the projector since it is plugged into an outlet in the attic and the rest of my HT gear is plugged up in the living room (I thus probably have a difference in ground 'potential'). I put a cheater plug on the Z1's plug and it worked! The XP30 is hooked up to both RPTV and Z1 and I have no rolling lines! Now, is it safe to leave it that way? Will there be any negative affects? Can it negatively affect picture quality?

thanks!
Jim

 

[Chu Gai]

Well it's either that Jim or hunting down the source of the ground loop which could be something in the cable feed that's not grounded properly. Some have had positive results from hooking all their stuff into a common receptacle but I don't know if that's going to work for you. Another thought are the video isolators from Jensen Tranformers.

BTW, I concur with your prequel comment.

 

[HienD]

I wouldn't recommend doing that. There is a reason the ground is there. Potential to harm the equipement and cause electrical fires. Maybe you can try a better surge protector or a line conditioner?

 

[Jim A. Banville]

Maybe you can try a better surge protector or a line conditioner?

No offense, but this sounds like something a "sales associate" at Circuit City would say. I have a ground loop issue caused by varying ground potentials. Unless the above mentioned items were so poorly designed that they broke their own ground connections, they wouldn't do anything to help my problem. Again, nothing personal

 

[Chu Gai]

You might want to see where that incoming cable is grounded Jim. I think a good spot would be the grounding rod, no?
I did read on another thread where someone had plugged all their equipment into one protector including the cable and that took care of their problems.

 

[Jim A. Banville]

My cable is grounded at the circuit breaker box. I don't know how the circuit box is grounded. I assume a cold water pipe since my home is on a slab and I don't see any copper rods pounded into the ground. I have ordered a Xantech "ground breaker" that goes in line with the cable-TV feed to try and solve the problem.

 

[Chu Gai]

A bunch of products perform in similar fashions. Post back with your results

Well you could always try and trace how it's grounded!

 

[Chuck Kent]

Jim: Sounds like you have a decent understanding on what's going on. I think you kinda already knew that under normal circumstances, using a cheater plug probably doesn't hurt anything.

Should you use one? I think you also know that the answer is no. The issue is that if the neutral connection in the circuit (in question) fails or becomes intermittant, components plugged in that circuit could have AC voltage on their cases or connections. The ground on a 3 pronged plug provides a 2nd "safety" pathway for failed or failing neutrals.

For the moment though, let's assume the circuit is in good shape and using the plug won't hurt anything. You still have a problem in that there appears to be more than one grounding path in your home. Which is not an unusual thing. Other than the interference you've noticed, this also represents a risk of having troubles if lightning ever strikes your home. Lightning seeks a pathway to the best ground. If you have more than one ground, have a poor ground, or even no ground, then lightning surges will have no "good" pathway and lord only knows what could happen. Bottom line is that if you can afford to do it right, make sure you have proper grounding and tie all of the grounds in your home to a common point. This is consistant with my layman's understanding of the National Electric Code and it also makes good sense...

 

[Jim A. Banville]

Bottom line is that if you can afford to do it right, make sure you have proper grounding and tie all of the grounds in your home to a common point.

I'm quite sure that my eletrical system is set up correctly, being a 2 year old home. The cable splitter inside the plastic box mounted on the exterior of my house has a green wire that attaches to it and runs to the circuit box mounted on the interior of that same wall. So one would assume that all grounds are connecting together. I also now understand the safety reasons for the 3rd prong, but due to my circumstances I'm not very worried about it. (1) new home/current code eletrical installation (2) non-metal housing on the projector (3) if 3rd prong was THAT important for 120V items, EVERYTHING would have one.

 

[Gary Silverman]

Jim, I also would be one to say there is a ground problem somewhere. Just because it's a fairly new house doesn't exclude poor workmanship in an installation.
Something you could do, I suppose, is install a GFI receptacle in the problem location and don't wire the ground to it. Then use the "cheater" adapter. The code allows a GFI receptacle where there is no ground, so this should be a legimitate fix, and won't compromise your safety.