One more time . . .
Please cite anywhere in the NEC / CEC / Any industry standard that affirms the above?!?!
Is reddit right about copper cables between buildings?
- Thread starter Webfont
- Start date
Please cite anywhere in the NEC / CEC / Any industry standard that affirms the above?!?!
I am very familiar with Lightning and best practices / industry standards to mitigate the same. Since you went out of your way to declare you're an Electrical Engineer.
Why would you promote and affirm an installation method that flies in the face of all known standards and best practices???
How about you explain to me and everyone else on this forum what should be done if copper wire is to be run and connected to two different building structures with a separate grounding system?!?! 
tigerwillow1
Known around here
For me anyway, one of the documents I linked to in post #17 explained this clearly:
"Environment B, the stricter isolation requirement, is for PSEs attached to Ethernet cables that cross an ac power distribution boundary. That is, electrical equipment near at least one cable connected to the PSE is wired to a different earth ground than the PSE or equipment near another cable. To prevent hazardous shocks due to different ground potentials at the end of each cable, Environment B PSEs have electrical isolation between all of their PoE ports; each pin in every RJ-45 jack must be electrically isolated from the PSE's chassis and the pins in all the other RJ-45 jacks on the PSE."
This document is specifically about POE switches, but I'll point out that all non-poe switches have the same or stricter isolation requirements. Those are in the "Review of IEEE 802.3 Isolation Requirements" section of the other linked document. Note that equipment damage isn't even mentioned as an issue. It's about the personnel risk if multiple PSEs add their floating PSE voltages to a point where it's a shock hazard.
I'm going to try to keep this very simple for everyone. The question being asked by me to the so called Electrical Engineer.
What are the first steps to mitigate a voltage potential?!?! If we ask the hard question which relates to Lightning what and how should said copper cable be installed?!?! We're not even at the point that addresses how the two will be terminated.
Nor, are we at the point trying to address how the site is installed, grounded, isolated, etc.
Because what the real question should have been is How do I connect two buildings using separate different grounding systems - safely, correctly, and to accepted industry standards.
wpiman
Pulling my weight
Ethernet is magnetically coupled. There is no ground wire in it. Thus, there are no grounding issues.I am very familiar with Lightning and best practices / industry standards to mitigate the same. Since you went out of your way to declare you're an Electrical Engineer.
Why would you promote and affirm an installation method that flies in the face of all known standards and best practices???
Often, you use shielded wire where you ground the jacket... You need to look out for ground loops in that case...
Someone posted this a while back...
How to Fix a Ground Loop
Ethernet cables are essential for connecting devices, but improperly installed shielded cables can cause frustrating ground loop issues. In this post, Don explains what causes ground loops and provides clear instructions for properly grounding shielded Ethernet cable runs. Learn the difference...
www.truecable.com
There are literally MILLIONS of buildings connected by copper ethernet with different power sources and grounds. The whole magnetics portion of the standard is designed precisely for this reason.
Obviously follow whatever codes are in your local area.
And I personally am a fan of running fiber in this case as well, but it isn't required.
As I suspected, please just stop offering bad advise . . .Ethernet is magnetically coupled. There is no ground wire in it. Thus, there are no grounding issues.
Often, you use shielded wire where you ground the jacket... You need to look out for ground loops in that case...
Someone posted this a while back...
How to Fix a Ground Loop
Ethernet cables are essential for connecting devices, but improperly installed shielded cables can cause frustrating ground loop issues. In this post, Don explains what causes ground loops and provides clear instructions for properly grounding shielded Ethernet cable runs. Learn the difference...
There are literally MILLIONS of buildings connected by copper ethernet with different power sources and grounds. The whole magnetics portion of the standard is designed precisely for this reason.
Obviously follow whatever codes are in your local area.
And I personally am a fan of running fiber in this case as well, but it isn't required.
wpiman
Pulling my weight
It is perfectly sound advice. It is also sound to use optics... both decouple the buildings.As I suspected, please just stop offering bad advise . . .
The back peddling and mental gymnastic one has to do to accept what you have stated here is simply incredible. As stated very plainly show me where in the NEC / CEC / Any standard that affirms what you said there will be no grounding issues much less says it's OK to do so???
Show me . . .
I also replied to another forum member as to what should be The Plan before one endeavors to start such a project???
I'll wait with abated breath as to the answers to the questions I posed up above from you.
Because, after all You're an Electrical Engineer!
wpiman
Pulling my weight
Yes. ASIC designer. I posted the grounding concerns if one chosen to use shielded wire. I recommend ubiquiti surge protectors at each end.The back peddling and mental gymnastic one has to do to accept what you have stated here is simply incredible. As stated very plainly show me where in the NEC / CEC / Any standard that affirms what you said there will be no grounding issues much less says it's OK to do so???
Show me . . .
I also replied to another forum member as to what should be The Plan before one endeavors to start such a project???
I'll wait with abated breath as to the answers to the questions I posed up above from you.
Because, after all You're an Electrical Engineer!
I don’t have time to look for the Canadian code. Don’t care if you take my advice. The cable modem systems connect to all houses and don’t use optics either. This is basic stuff.
you an electrician? They tend to go by the code and not understand the fundamentals.
This is your professional Engineering answer / reply to a valid question???
As you stated it is Basic Stuff which is clearly out of your depth of field. It's so basic you can't even answer that simple question posed by another forum member?!?!At the end of the day every other reply you offered only happened AFTER you were challenged to provide substantiating facts.
You continue to ignore all the prep and considerations as to grounding . . .
tigerwillow1
Known around here
For communications circuits, NEC article 800 says that surge protectors may or may not be required based on lightning exposure and earth resistivity. It also gives guidelines for terminating metallic sheaths for runs between buildings. Where does it require a metallic sheath? I can't find it. If no metallic sheath, no grounding issues. just as wpimamn has been trying to say. The isolation requirements of IEEE 802.3 and IEC 60950-1, if you understand them, say there are no issues with respect to the different grounding systems.
Show us where they say there WILL be grounding issues. Or do you want to just continue throwing rocks?
wpiman
Pulling my weight
Lightning mitigation is never a bad idea. Neither is using optical.
Ethernet wires between building never “touch” so the buildings are isolated. We routinely run Ethernet from hangers to planes and they have a ground and a floating ground. All is good. If you are designing an Ethernet switch-
You ground your end and magnetically couple to the line.
Ethernet is designed so you don’t have to worry about grounding- at least temporarily. Lightning mitigation is trickier for long term connections.
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wpiman
Pulling my weight
wpiman
Pulling my weight
Sorry. You don’t know what you are talking about. Grounding is not an issue at all because Ethernet over cat5/cat6 is magnetically coupled.This is your professional Engineering answer / reply to a valid question???
At the end of the day every other reply you offered only happened AFTER you were challenged to provide substantiating facts.
You continue to ignore all the prep and considerations as to grounding . . .
only in shielded cables does this question ever come up.
the ethernet spec is designed so that users can connect without worrying about such problems. For example, you sit on your couch with Ethernet plugged into your laptop. Not a problem. The is because the 4 incoming wires are differential and have no reference for ground. Same as you cable modem.
Sybertiger
Known around here
Hmm, maybe I don't get it. Run burial Cat6 to son's house to power the cams via a POE switch in your house. You wouldn't be tapping into his power at all therefore no ground issues. This isn't any different than if you ran the Cat6 outside to cams on yours or his trees or in his kitchen for that matter as nothing would be on his power grid.
Sybertiger
Known around here
BTW, the ground bond to neutral is a safety issue regarding a short from hot to the metal chassis of the/any device. Theoretically, this safety mechasim would never ever be utilized over it's lifetime in a properly wired home. And, this ground has nothing to do with induced voltage from the magnetic field of a lightning strike. The lightning induce voltage is handled by a different grounding mechanism. That is, the solid copper line that runs down to the 6 foot solid copper grounding rods driven into the ground near your power meter.
tigerwillow1
Known around here
Lots of context here. The very first post says he wants to have the POE switch in the son's house, Post 9 explains that he wants to have 7 cameras, and the actual wire distance between the houses is 130 feet. The irony is that the grounding and surge protection requirements in NEC are the same, regardless of which house the cameras are powered from. If anybody reads it differently I'd like to see it explained.
If we want to start throwing regulations around, I'll stick my neck out and say that over 90% of forum members with cameras located away from the house are busting the NEC for burial depth and/or surge protection. Even some the professionally installed and inspector approved buried power lines on my property bust the depth requirements.
Sybertiger
Known around here
I'm guilty of not reading all the back and forth. I first read "10 feet and some cameras". LOL, they always add to their requirements after.
POE is good for 320 feet but I guess he doesn't want to run his now 7 lines but rather just one main switch to switch connection.
Twisted pair ethernet is a differential electrical protocol as was pointed out. Most folks are not utilizing the ground shield anyway. But, fiber optic or wireless transceiver communication (not WiFi - wireless bridge) are other options.
POE is good for 320 feet but I guess he doesn't want to run his now 7 lines but rather just one main switch to switch connection.
Twisted pair ethernet is a differential electrical protocol as was pointed out. Most folks are not utilizing the ground shield anyway. But, fiber optic or wireless transceiver communication (not WiFi - wireless bridge) are other options.
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alastairstevenson
Staff member
Not strictly correct.
When PoE is used - there are direct connections to the internal circuitry, and therefore often to the body or case, of both the PD (Powered Device) and the PSE (Power Sourcing Equipment) as those who have mounted metal bodied cameras to metal flashing well know.