Cable T.V. Ground /Bond

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jehobden

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Lamar, Colorado
Just have a some Questions. I work for Charter communications and there is always some disagreement on proper bonding. If you have a MDU where your services are well away from the Bldg groung is it acceptable to drive a ground rod and not run a line around to the service ground of the Bldg.(close to 100' away) the tap is closer to the service but not individual splitter boxes/
Can the Taps be grounded and not the individual drop?

What about if you cannot get to a service ground(older stucco houses) is that something that the customer should be forced to provide)

Can you explain why a loose ground/bond is a bad thing..( We have one employee that doesn't believe it makes a difference..)
 
jehobden said:
Just have a some Questions. I work for Charter communications and there is always some disagreement on proper bonding. If you have a MDU where your services are well away from the Bldg groung is it acceptable to drive a ground rod and not run a line around to the service ground of the Bldg.(close to 100' away) the tap is closer to the service but not individual splitter boxes/
Can the Taps be grounded and not the individual drop?

What about if you cannot get to a service ground(older stucco houses) is that something that the customer should be forced to provide)

Can you explain why a loose ground/bond is a bad thing..( We have one employee that doesn't believe it makes a difference..)
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There is an exception in 820.100(A)(4) for one and two family dwellings where it is not practical for the grounding electrode conductor to be 20 ft or less to drive a separate ground rod. But it still requires no less than a #6 CU between the CATV ground rod and the power ground rod at the building :D. Bonding together of all separate electrodes limits potential differences between them and between their associated wiring systems.
 
jehobden said:
Just have a some Questions. I work for Charter communications and there is always some disagreement on proper bonding. If you have a MDU where your services are well away from the Bldg groung is it acceptable to drive a ground rod and not run a line around to the service ground of the Bldg.(close to 100' away) the tap is closer to the service but not individual splitter boxes/
Can the Taps be grounded and not the individual drop?

What about if you cannot get to a service ground(older stucco houses) is that something that the customer should be forced to provide)

Can you explain why a loose ground/bond is a bad thing..( We have one employee that doesn't believe it makes a difference..)
Click to expand...

You can also bond onto any bonded equipment per 250.52. I can tell you tho that when Continental Cablevision put cable in these neighborhoods back in the early 80s, the SOP was a ground rod driven at the NID and a piece of bare #14/#12 run from the ground block/1st splitter, and no GEC run back to the panels.

It is rare but possible for the coax braids/shield to become a return path for 120/240VAC; see this link:

http://www.electrical-forensics.com/Open-Neutral/Open-Neutral.html

istm a case for separately grounding the CATV but the NEC does not concur.
 
The benefit of bonding is that you (mostly) prevent current from flowing on the coax *inside* the home. Melted coax is more of a fire hazard indoors.
 
In a related story...

A friend of mine bought a small travel trailer that was outfitted for 120V shore power by its former handyman owner. My friend parked it next to his house for sort of a mancave, and he put a splitter on his CATV line outside the house and ran cable out to the trailer. In the process of getting things hooked up the RG6 connector on the cable came in contact with an aluminum window frame in the trailer, and it arced and melted a spot on the frame.

When the handyman wired up the ungrounded "Aggie extension cord" (male on both ends) for shore power he got hot and neutral reversed, tied "neutral" and ground together in the trailer, and tied "ground" to the frame of the trailer. The frame was at 120VAC to earth ground, hence the arcing to the CATV connector. We are lucky no one was electrocuted stepping in or out of that trailer.
 
Thinking about this a bit more, the safest thing would be to isolate the outside cable from the inside. The inside cable would be bonded/grounded as usual. The outside cable would not be bonded or grounded at the home, preventing the cable drop from being a parallel neutral.

Cable TV "ground isolators" seem to cost around $20. I wonder what a cable TV tech would think if he saw one installed?
 
ggunn said:
In a related story...

A friend of mine bought a small travel trailer that was outfitted for 120V shore power by its former handyman owner. My friend parked it next to his house for sort of a mancave, and he put a splitter on his CATV line outside the house and ran cable out to the trailer. In the process of getting things hooked up the RG6 connector on the cable came in contact with an aluminum window frame in the trailer, and it arced and melted a spot on the frame.

When the handyman wired up the ungrounded "Aggie extension cord" (male on both ends) for shore power he got hot and neutral reversed, tied "neutral" and ground together in the trailer, and tied "ground" to the frame of the trailer. The frame was at 120VAC to earth ground, hence the arcing to the CATV connector. We are lucky no one was electrocuted stepping in or out of that trailer.
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Well, that's a novel way to protect from burglars too. :D Lucky indeed.

From what Ive seen, CATV is extremely forgiving of wiring/termination errors, pinched cables,etc. I would suspect this is because the outside plant (aerial/underground) is never touched by DIY/hacks and actually designed right, so it really takes a dedicated effort to hose it up the last 50 or 100' (i.e., your house). Early on I took pictures of the junk I ran across; I stopped in six months because it was pretty much all like that.

Gene, I dont know, I've never seen one installed. Most people will just deal with the crappy signal or low internet speed, or fried eqpt. Occasionally one will call and 'the usual' fix gets them straight, 'the usual' being reterminating everything with compression fittings, eliminating unnecessary splitters, putting the modem on the first splitter, capping unused lines. Best $100 worth of tools and 20 minutes for training I ever spent.
 
K8MHZ said:
The only fiber for miles around here is fruit and vegetable fiber. I am a 10 minute drive from the edge of rural Michigan that doesn't even have cable, DSL or natural gas.
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While I'm old enough to not get the shakes at the idea of not having internet or cable, what do folks "beyond the Pale" do? Satellite?
 
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