Bad grounding setup (pics)

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brantmacga

brantmacga

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Georgia
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Former Child
Customer complained that several TV's have been "popped" over the past couple of years.


noground.jpg


cableground.jpg


grounds.jpg


No, that ground wire in pic #1 wasn't connected to anything.
 
stickboy1375 said:
Would that cause anything else other than ground loops?
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Lightning induced voltage may just find a path from coax, through TV, to electrical system. Tvs might not like that. That is why all systems are supposed to be bonded together.

At least that is how Mike Holt explained it in his G vs B semanar.
 
JohnJ0906 said:
Looks like the cable installer owes the HO the cost of a few TVs...;)
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I know the guy who installed this, as this cable company only has one installer and he's been doing it since they first started offering cable TV, I think. I told the HO there was a slight chance this caused it, but told them there was no way to prove it. Do you guys think it would be inappropriate to go talk to the cable installer about this? He installed the cable on my house along w/ a wireless internet antenna coming into the house on LMR400 coax. Neither of them were grounded to my service so I had to do that myself.
 
You would never prove it. But it is a real possibility. Could be something else.

However, you might explain that it is required to be bonded to the service GEC, or electrode. (See 820.100, there are several methods)
 
JohnJ0906 said:
You would never prove it. But it is a real possibility. Could be something else.

However, you might explain that it is required to be bonded to the service GEC, or electrode. (See 820.100, there are several methods)
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Yeh I didn't mean it to sound like I was going to go on a witch hunt. I just feel like I may be doing him a favor by pointing these things out. You never know what kind of liability suit might get slapped against them for improper installs.
 
JohnJ0906 said:
Lightning induced voltage may just find a path from coax, through TV, to electrical system. Tvs might not like that. That is why all systems are supposed to be bonded together.

At least that is how Mike Holt explained it in his G vs B semanar.
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I figured it was more for possibility of damage to the systems from potential (voltage) differences between the systems, not as much as lightning, bonding the catv to earth will hopefully prevent any surface arcing though.
 
brantmacga said:
I know the guy who installed this, as this cable company only has one installer and he's been doing it since they first started offering cable TV, I think. I told the HO there was a slight chance this caused it, but told them there was no way to prove it. Do you guys think it would be inappropriate to go talk to the cable installer about this? He installed the cable on my house along w/ a wireless internet antenna coming into the house on LMR400 coax. Neither of them were grounded to my service so I had to do that myself.
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You need to explain it to him so he understand the risk to life and property..other wise someone will take pictures and when it destroys something share them with the insurance company when they are done he will be financially broke and in debt..You need to do it for your friends and customers to educate him..
 
Separated grounding systems almost assures that there will be a potential between them during a lightning event.
 
LarryFine said:
Separated grounding systems almost assures that there will be a potential between them during a lightning event.
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Exactly. It may be less important to have a "good ground", than to have all communications systems bonded together to minimize the difference of potential in lighting or line surge. The voltage is elevated but all elevated together. Thats why the 2008 NEC requires a intersystem bonding terminal.
 
tom baker said:
Exactly. It may be less important to have a "good ground", than to have all communications systems bonded together to minimize the difference of potential in lighting or line surge. The voltage is elevated but all elevated together. Thats why the 2008 NEC requires a intersystem bonding terminal.
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If lighting hits, everything is going to be fried anyways, so is bonding of all systems for lightning or just voltage difference potentials?
 
stickboy1375 said:
If lighting hits, everything is going to be fried anyways, so is bonding of all systems for lightning or just voltage difference potentials?
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It is for lightning induced voltage - indirect strike. Voltage can be induced on metal objects by an indirect strike.

As I understand it, if you had 2 seperate GEs, the voltage induced would be different, depending on the distace from the strike. That voltage would go through the coax, through the equipment, through the EGC, to the service (2nd electrode). If the electrodes are bonded, or only one is used, then this problem is reduced.

Direct strike - not a whole lot we can do about that.
 
This tv cable install doesn't look like it was done by the local tv cable company from what I see in the pictures. No rubber boots on the exterior connections to the splitter is one thing. Most of the trained guys working for the cable companys know how to get a good bond to the service or gec also. Maybe it was done by one of those Craigslist sattelite guys.
 
macmikeman said:
This tv cable install doesn't look like it was done by the local tv cable company from what I see in the pictures. No rubber boots on the exterior connections to the splitter is one thing. Most of the trained guys working for the cable companys know how to get a good bond to the service or gec also. Maybe it was done by one of those Craigslist sattelite guys.
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Very well could be. I know the cable company here (a rather LARGE one) subs out all of there residential work. You see guys all the time driving around in there beat up trucks with the cable companies magnetic sign on the side. I doubt they get very much training if any on service installations.
 
Chenley said:
Very well could be. I know the cable company here (a rather LARGE one) subs out all of there residential work. You see guys all the time driving around in there beat up trucks with the cable companies magnetic sign on the side. I doubt they get very much training if any on service installations.
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Wow. In that case could be. Here it is all in house and done quite well most all the time. The local cable guys could use a little training in concealing cable runs however....
 
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