Does the NEC cover low voltage (isn't what we're talking about considered low voltage)? Also, you haven't explained how the two pictures are different electrically. The second one is still a 'shared ground'.
Avoiding ground loops (or not!)
- Thread starter MikeInAlaska
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Shared grounds are specified OK or not OK on a panel by panel basis for 120V / 240V eqpt. For example my Siemens panels all say it is OK to put two grounds under a screw, but not OK to put two neutrals under a screw.
It is good to know this rule for the NEC code, but it will make absolutely no difference either way it is wired to the OPs orignial ground loop question.
This has generated a lot of interesting talk, but I think most of it has missed the target.
My house has all incoming coaxial grounded at the outside wall using grounding blocks like pictured.
This is concerning coaxial cables coming from wallplates all over the house, into a single central closet where they will all be terminated, and where the DPP33 switch lives.
The question is, in this wiring closet, if all the coaxial shields are tied together in the central closet, do the resulting ground loops (which WILL form and conduct current through the ground shields) do these ground loops cause problems?
Hopefully it doesnt seem like "Much Ado About Nothing", it was expensive putting dual RG6 to every wallplate in the house, and its expensive terminating them all in the central closet, so I dont want to screw up here - at the very end - (of the projects and the cables ; )
My house has all incoming coaxial grounded at the outside wall using grounding blocks like pictured.
This is concerning coaxial cables coming from wallplates all over the house, into a single central closet where they will all be terminated, and where the DPP33 switch lives.
The question is, in this wiring closet, if all the coaxial shields are tied together in the central closet, do the resulting ground loops (which WILL form and conduct current through the ground shields) do these ground loops cause problems?
Hopefully it doesnt seem like "Much Ado About Nothing", it was expensive putting dual RG6 to every wallplate in the house, and its expensive terminating them all in the central closet, so I dont want to screw up here - at the very end - (of the projects and the cables ; )
I don't believe that you should have any ground problems that would be caused by connecting the coaxial shields together.
If everything is grounded (bonded to ground) properly, as you say, there shouldn't be a problem.
If, however, you find ground loop interference after installation, changing the method of termination is not the solution. It would only mean that the grounding is not correct on one or more components requiring ground, it wouldn't be the fault of your termination. The solution would be to repair the bonding (ground) of the offending piece of equipment.
If everything is grounded (bonded to ground) properly, as you say, there shouldn't be a problem.
If, however, you find ground loop interference after installation, changing the method of termination is not the solution. It would only mean that the grounding is not correct on one or more components requiring ground, it wouldn't be the fault of your termination. The solution would be to repair the bonding (ground) of the offending piece of equipment.
if you've grounded the system (leviton can and it's cables) at the d-mark( electrical ground outside) you're good to go.
Do not ground anything else inside the house. That MAY create a ground loop.
In the end I ended up using Leviton 2.5 ghz barrels in their quickport jacks. I went with blank 12 position plates and loaded them up for a fairly dense 48 coax patch bay. (Could be a lot denser if they would make some larger plates.)
Some pics..
Some pics..
Wow, that really looks good. My only concern is it doesn't look like you have any slack on your cables. If you have to cut an end off and replacement (for who knows what reason), it doesn't look like it will fit back on the same connector.
Hi Sam, indeed I did leave generous loops above them which can be pulled down. They can all be pulled a couple inches. Additionally the entire Leviton blocks can be raised several inches to produce up to 3 inches or so of slack per cable.
By the way, I have found the 200ft specified cabling limits to be very conservative.
Maybe its the all copper RG6? or the expensive connectors? I have tested most of the drops around my house by sending the satellite signal out and looping it back at the wallplate, adding anywhere from 60-100 feet of cable in an already long run. I do not see much difference in the reported satellite levels on the check screen.
I should take it to failure and see how many feet you can really use on a DPP post-switch and pre-switch.
Maybe its the all copper RG6? or the expensive connectors? I have tested most of the drops around my house by sending the satellite signal out and looping it back at the wallplate, adding anywhere from 60-100 feet of cable in an already long run. I do not see much difference in the reported satellite levels on the check screen.
I should take it to failure and see how many feet you can really use on a DPP post-switch and pre-switch.
No difference
All copper makes no difference. Electricity is carried on the skin of the conductor and so the center of it can be steel with copper skin and it will work as well as the all copper. The only advantage to all copper is it is easier to bend than the stiffer steel with copper coated cable.
All copper makes no difference. Electricity is carried on the skin of the conductor and so the center of it can be steel with copper skin and it will work as well as the all copper. The only advantage to all copper is it is easier to bend than the stiffer steel with copper coated cable.
> You sir, have mad wiring skillz.
thanks : )
> All copper makes no difference.
The reason I brought that up is because one of the Dish receiver manuals said you may actually need to temporarily put the receiver on a short run of cable to update the receiver, OR, switch to an all copper cable in order to get the initial box update to complete. I can NOT find this quote now and its driving me nuts, please someone tell me I didnt imagine reading this somewhere.
thanks : )
> All copper makes no difference.
The reason I brought that up is because one of the Dish receiver manuals said you may actually need to temporarily put the receiver on a short run of cable to update the receiver, OR, switch to an all copper cable in order to get the initial box update to complete. I can NOT find this quote now and its driving me nuts, please someone tell me I didnt imagine reading this somewhere.
> All copper makes no difference. Electricity is carried on the skin of the conductor and
> so the center of it can be steel with copper skin and it will work as well as the all copper.
> The only advantage to all copper is it is easier to bend than the stiffer steel with copper
> coated cable.
I found the reference I was looking for, in this Dish Pro Plus installation document:
http://www.satelliteone.com/support...lation_Information_Special_Considerations.pdf
I quote:
If the RG-6 to be used in this installation includes copper-clad steel center conductor, one of the following may be needed to complete the receiver software upgrade. After the software upgrade is completed, the following measures are no longer needed for future receiver operation.
- Cable length must be shortened to 100 feet maximum.
- Temporarily install RG-6 cabling with solid copper center conductor up to 200 feet between
the receiver to the DP Plus Twin.
> so the center of it can be steel with copper skin and it will work as well as the all copper.
> The only advantage to all copper is it is easier to bend than the stiffer steel with copper
> coated cable.
I found the reference I was looking for, in this Dish Pro Plus installation document:
http://www.satelliteone.com/support...lation_Information_Special_Considerations.pdf
I quote:
If the RG-6 to be used in this installation includes copper-clad steel center conductor, one of the following may be needed to complete the receiver software upgrade. After the software upgrade is completed, the following measures are no longer needed for future receiver operation.
- Cable length must be shortened to 100 feet maximum.
- Temporarily install RG-6 cabling with solid copper center conductor up to 200 feet between
the receiver to the DP Plus Twin.
I believe you are referring to the "skin effect" which comes in to play at frequencies above 10 KHz for copper conductors with the gauge used in RG coax. DC (used to transmit power to the LNBs and to some Dish switches) travels by using the whole diameter of the center conductor. Using a solid copper center conductor allows you to supply more power over a longer distance than using copper-clad steel.
Dish's 100' limit is not an RF limit, it's driven by the voltage drop caused by the higher DC resistance of steel. Copper-clad cable is also cheaper than solid copper which is another reason to use it when distance is not a factor. I've also heard that copper-clad steel is recommended if you have unsupported runs of coax as the copper-clad steel is much stronger than solid copper.
deathcow, I appreciate all the work you have in your wiring closet. I am still in the process of getting my Litton enclosure finished up, but I need to get the trunk between the upstairs closet and the basement installed. My plans call for running a 2" interduct which should be enough for 8 RG6 and 8 CAT5e cables. It sure would be a lot easier if I wasn't retrofitting into a 22 year-old house.
Thanks for the input, quite interesting. The big trunk from upstairs to downstairs is a great idea, you wont regret that. Our house was a 1 story log cabin, we lifted it, which produced (poof! from thin air) a daylight basement with entirely exposed floors above. I took that opportunity to run all these cables. My one wish would be that I'd have put in more raceways THROUGH the upstairs level so I could cable between the basement and above the ceilings of the (now) upstairs.
Isn't that weird though that Dish says you might need to reduce (by half!) the amount of copper clad steel in order to get the receiver update to complete, then you can go back to the long cable.
Mike in Alaska
Isn't that weird though that Dish says you might need to reduce (by half!) the amount of copper clad steel in order to get the receiver update to complete, then you can go back to the long cable.
Mike in Alaska
Correct
RF i s carried on the skin but VDC carried by the whole conductor. Even full copper isn't really full copper it's combination of metal. Pure copper is to soft for anything except carrying video.
RF i s carried on the skin but VDC carried by the whole conductor. Even full copper isn't really full copper it's combination of metal. Pure copper is to soft for anything except carrying video.
So why does Dish network say that updating the receiver may require these special cabling provisions that normal operation of the receiver does not?
