Quick Question From A New Member

[jtrockville]

How many NEC violations are shown in this pic?

 

[bennie]

Re: Quick Question From A New Member

Huh?

 

[al hildenbrand]

Re: Quick Question From A New Member

Looks to me to be on the utility side of the cable system demarcation point. Generally this is outside of the purview of the NEC.

 

[jtrockville]

Re: Quick Question From A New Member

I'm sorry, bear with me please, but I don't know what that means, "the utility side of the cable system demarcation point".

The NEC codes do not apply to utility equipment in the ROW?

That splitter doesn't need to be grounded somewhere?

btw - There is no ground at the point of entry to the customer's home either.

Thank you for your information and patience.

 

[Thom Peterson]

Re: Quick Question From A New Member

Cable system at the utility pole line is covered under NESC.

 

[dereckbc]

Re: Quick Question From A New Member

To answer your first question "how many NEC violations are there"? Answer, none.

The splitter shown appears to be on the utility side of the demarcation point, and as others have indicated has nothing to do with NEC requirements.

To answer your second question, "does the splitter need to be grounded"? No it does not need to be grounded as it would serve no purpose.

The demarcation point is a point where the cable transsisitons from the cable company's ownership to the customer's ownership of the cable. For CATV it is usually a surge arrestor mounted on a building where the service lateral enters. It looks like a coax splice with a ground screw. It is from this point where the CATV needs to be grounded to the electric service electrode as covered by NEC 820.40

[ May 22, 2003, 04:58 PM: Message edited by: dereckbc ]

 

[jtrockville]

Re: Quick Question From A New Member

Originally posted by Thom Peterson:
Cable system at the utility pole line is covered under NESC.

nesc.org National Executive Service Corps
nesc.ie National Economic and Social Council
nesc.com National Executive Staffing Company

Ah HAH!
NATIONAL ELECTRIC SAFETY CODE

Thank you very much.

 

[jtrockville]

Re: Quick Question From A New Member

Originally posted by dereckbc:
For CATV it is usually a surge arrestor mounted on a building where the service lateral enters. It looks like a coax splice with a ground screw. It is from this point where the CATV needs to be grounded to the electric service electrode as covered by NEC 820.40

You're describing a ground block (a term I recently learned)? There isn't a ground where it enters the building.

I apologize if these questions are inappropriate for this forum, but I don't know where else to ask.

You say it would serve no purpose to ground that splitter, but what would happen to the cable plant if, during a storm, a tree limb dropped and brought a powerline down on it?

(I'm scared to ask what would happen to customer premise equipment, given there's no ground at the "demarcation point")

 

[dereckbc]

Re: Quick Question From A New Member

You're describing a ground block (a term I recently learned)? There isn't a ground where it enters the building.

You are correct, it is called the ground block. However, that is the point where the CATV is grounded before entering the building. It is a requirement of NEC 820.40. It is to protect the building or house incase the CATV comes into contact with high voltage lines or discharge lightning strikes.

You say it would serve no purpose to ground that splitter, but what would happen to the cable plant if, during a storm, a tree limb dropped and brought a powerline down on it?

The same thing that would happen if the splitter were not there. The splitter is attached to another splitter right above it which is bonded to the grounded messenger. The splitter's enclosure case in question is electrically the same as the coax shield. To add a short ground wire from the splitter enclosure case to the splitter above it would serve no purpose from a safety or technical view point. The shield of the CATV line is bonded to the pole grounds along the way.

If a power line were to fall on the CATV line and and by some chance make electrical contact, the voltage would travel in all directions. On the CATV line side, it would travel to the nearest pole grounds and return to its source via ground there. As far as your house or building goes it will be return to the source via the ground block if installed properly.

Besides, I think you are overlooking that the CATV coax is mounted on the messenger wire. The messenger wire is grounded to every pole attachment. The electric utility static line is the neutral or grounded conductor, and is also bonded to pole ground. If a power line were to fall it would make contact with the messenger first. It is highly unlikely the utility line would make contact with the coax, but if it did the provisions are there to take care of it.

[ May 22, 2003, 11:48 PM: Message edited by: dereckbc ]

 

[jtrockville]

Re: Quick Question From A New Member

Originally posted by dereckbc:
If a power line were to fall on the CATV line and and by some chance make electrical contact, the voltage would travel in all directions.

Originally posted by dereckbc:
It is highly unlikely the utility line would make contact with the coax, but if it did the provisions are there to take care of it.

I'm making an assumption here, and please correct me if I'm wrong: the purpose of these electrical codes is to protect us in these unlikely situations.

Originally posted by dereckbc:
The shield of the CATV line is bonded to the pole grounds along the way.

Originally posted by dereckbc:
Besides, I think you are overlooking that the CATV coax is mounted on the messenger wire. The messenger wire is grounded to every pole attachment.

You seem to be making an assumption that things are generally done properly. I'm trying to convince myself you're right, but I'm having trouble.

I came across an inspection report of our cable plant. Even though I don't fully understand it (or maybe BECAUSE I don't understand it), it scares me. I've snipped it for your convenience.

Inspection Report:

The County continuously inspects the quality of the in-progress construction work and the resultant physical cable plant and equipment in the public rights-of-way. These inspections verify the extent to which the construction complies with the engineering design, construction standards for physical cable plant, installation of equipment on the cables, safety of work-in- progress, and the restoration of work areas after construction is completed.

(snip)

After construction is complete, the physical plant and construction work areas are inspected to verify that construction and restoration of the work site complies with the standards required by the Franchise Agreement.

(snip)

The number of ?Construction? category violations for the first quarter accounts for nearly 60% of the total violations, slightly less than last quarter. Approximately 25% of the construction category violations are grounding related; half of those for no grounds where required. The other grounding problems found involved ground rods protruding too high out of the ground or above the pedestal base. There were many sites where there were ground rods and wires installed but the wires were simply not attached to the ground rods, which is effectively the same as no ground at all.

I can't tell whether the violations are at the building, or at the plant, or some of each. Can you?

Are there increased risks to customer equipment or plant equipment, if there is no ground at the building OR at the plant?

Thank you again for taking the time to reply. I really appreciate your patience.

 

[al hildenbrand]

Re: Quick Question From A New Member

JT,

A coaxial cable is grounded. The only part of a coax that is not grounded is the single conductor inside the white stuff (dielectric) at the center of the cable. In the picture you have posted, the aerial messanger will be bonded to ground balls or pole butt plates. The trunk splitter (shown in your photo) will be grounded by being hung from the messenger. The trunk splitter grounds the coax shield (under the black cable cover, but outside of the white stuff) thru the metal cable end connector. The short coax lead from the trunk splitter, then, in turn, grounds the body of the little third party splitter thru the other metal cable end connector. The third party splitter that you are concerned about, being grounded, then, in turn, grounds the two coax sheilds that lead on out of the picture.

It's all grounded.

 

[jtrockville]

Re: Quick Question From A New Member

Originally posted by al hildenbrand:
In the picture you have posted, the aerial messanger will be bonded to ground balls or pole butt plates.

It's not that I don't believe you... but I want to see this with my own eyes. I've never heard those terms before, and I'm scared to do a google search on "balls" and "butts"!!!

Could you suggest a place where I can see an example of a properly grounded messanger?