Ground loop

How would a ground loop occur with a camera.I just couldnt bother racking my brains trying to figure out how it happens

I have found it to usually be the difference in ground between the camera and the camera's power source. Rather then the difference between the camera and recorder as one might think.

another way to look at it is that every object (building A & building B) has a charge.........when unlike charges connect (video camera wire) that causes a difference in potinetial..........causing current to move one direction or the other......this movement of current can cause interferance in video signals.

So what your sayin is if you had a charge at the matrix,dvr or whatever the coax is connected to internally coax could act as a conductor or loop and current could flow down coax reachin the Camera.Would this only apply to external cameras or are internal subjected to the same conditions

most ground loops happean because of some way the camera or the cable has been grounded twice. once at at the dvr end and the other is the million dollar question.

if you think about the possible conditions that may cause GL you have more than just a few ways. I've seen/found different ones.ie. induced noise/GL from electrical lines, lites, strong power sources........near the camera cables. Screws that are used to mount the camera come into contact with metal conduit inside the walls or wiring. Ecectrical charging devices, like a charging unit for a sissor manlift, that put noise/GL onto camera pics. Water/moisture causing spuratic GL/noise. Placement of the monitor near a high magnetic or electrical source that caused bad pics.

I may have crossed the line on a few above but my point is that it can be created in many ways. First thing to do is make sure it is GL or noise.then try to find the source(s).

I have one at a large store here that every few days a few camera's start looking like hell....obviously induced noise. Turned out to be the charging unit for the sissor lift................main power line was running along side a few camera lines and when they plugged it in that created more current pull on that line which induced GL.......very strange but real.

How would you wire a ptz mounted on a pole outside would you use ground or earth on power supply transformer and do same back at supply for transformer coming out.If you isolate the camera so that it is 'floating, a loop should not happen is that what your sayin?

If you isolate the camera so that it is 'floating, a loop should not happen is that what your sayin?

It can still induct current.

Most PTZs are 24VAC and should not have ground loop issues.

EDIT: Left out the dang NOT again.

you are correct.............isolate is good.........but remember that GL has many sources/causes. practice "clean" install procedures and you'll reduce video problems upfront.

It's a weird issue that shows up more than not..ie. I've seen the cheapest cable run alonside power lines, over lights, thru power pannels, and the video is fine? But have one screw touch a metal conduit pipe in a wall and the bars start rolling?

My theory is that if the building AC electrical was installed properly, grounded and shielded, the issues of GL are reduced. Have one miswired ac run and that opens up everything to a GL.......

Collin, running on 24VAC accentuates the ground loop problem in my experience. If the ground point is different between your PS and the actual equipment ground you WILL have ground loop problems. i.e. equipment rack is grounded to building frame and PS is grounded via UPS feed. You would think these two points would be at the same ground potential... but not always. If there is a difference between to the two points you will have ground loop problems. Try floating the power supply from the rack (Altronix rack mounted) and see if it doesn't do away with the problem.

Collin, running on 24VAC accentuates the ground loop problem in my experience. If the ground point is different between your PS and the actual equipment ground you WILL have ground loop problems. i.e. equipment rack is grounded to building frame and PS is grounded via UPS feed. You would think these two points would be at the same ground potential... but not always. If there is a difference between to the two points you will have ground loop problems. Try floating the power supply from the rack (Altronix rack mounted) and see if it doesn't do away with the problem.

I haven't ever had a ground loop with AC current, as you pointed out building to building (maximizes your example) I have them almost 100% but it's just been on the DC stuff. I guess I shouldn't say it doesn't happen just because it hasn't to me.

Must be an OK thing too as most here seem to look to the video path for the loop whereas it seems both of us look straight to the power path. All I know is the okies are right on that one, it's most often on the power side...

ground loops are more prominent in ac

Just ran into this problem the other day, thanks to Isaac and his expert knowledge, we solved the problem in 5 minutes.

We had wavy lines from bottom to top, isaac said ground loop, my tech said no way, isaac said check the camera, pulled the camera from the housing, sure enough, there it was!

The camera surface mount adapter was grounding the camera to the steel beam it was mounted to.

We used nylon bolts and washer to isolate the mount from the steel beam!

Camera: Panasonic WV-CW484S

Power Supply: P3 24V AC, 16 Out, 25 Amp

800 Foot Home Run Cable, plastic zip ties (no breaks in the line anywhere)

Thanks Isaac!

wish i could say i knew that from being smart and not from my own experiences

Our installers commonly see ground loops and most of the time it is from a lazy electrician grounding to a metal I-beam or stub instead of running their ground line back to the earth ground.

That's right Collin, us Okies aren't tooooo backwards.

Another ground loop problem can come up when the electricians ground things to two ground rods, seperated by some distance. As the ground dries up a difference in potential can occur between the two grounds, causing ground loop problems. Solution .......100% IP.

Lynn Wagoner

Yukon, OK

This thread has addressed a problem I was having today. I am looking forward to seeing if I can resolve the problem by applying suggestions given here.

That's an interesting idea. I have 8 24vAC Sony box cams and 8 12vdc Speco Bullets, the bullets now have a ground loop that I haven't been able to get rid of, and I'm pulling my hair. The 24v AC cams are fine. And I have my scissorlift plugged into the same outlet!!!! Can't wait until Thursday to unplug that sucker.

[i have one at a large store here that every few days a few camera's start looking like hell....obviously induced noise. Turned out to be the charging unit for the sissor lift................main power line was running along side a few camera lines and when they plugged it in that created more current pull on that line which induced GL.......very strange but real.

I have had problems with the Vitek IRD32 cameras they are 24v ac. I tried filters etc and ended up with using either individual power supplies or changing the altronix 16 cam power supply to their isolated version. THis problem has cost me big bucks trying to figure it out as it has occured on this same site with two different buildings.