Proper CATV & Telephone service grounding?

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What are the accepted methods of grounding Cable TV / Satellite and Telephone cables at a residence?

In my area, most Electrical service appears to be grounded at the meter/ point of entry into the home; however, I have seen quite often that telephone or cable service is not grounded at the point of entry into the home, but only grounded at the green box out in the middle of the property somewhere. In my opinion, this leaves a ground loop path for lightning to get into the home, and cause damage.

820.33 describes grounding of outer conductive shield of coaxial cable. 250.4 describes grounding conductive materials enclosing electrical conductors at the electrical supply source, which I would interpret to be the meter or point of entry into the home. 820.40 describes the grounding conductor should not be smaller than 14 AWG.

Is my interpretation correct, and that both the cable and phone should be grounded at the point of entry to the home?

It would be appreciated if anyone could post some information what devices exist to bond the shield of RG6 cable to 14 AWG ground conductor, and the proper grounding methods of this cable and incoming telephone wires.

Erik Munevar


Staff member
Plano, TX
Re: Proper CATV & Telephone service grounding?

Erik, for the telephone cable you can find the answer in 800.40, satellite 810.21. CATV 820.40. They all say practically the same thing.

I will describe the telephone cable. The telephone company should install a NID where their line comes to the house. Inside the NID are some sort of protectors for the cable pairs, and a means of terminating the shield if equipped. There will be a ground terminal in the NID to connect to an electrode. The ground conductor should be a # 14 AWG or larger and limited in length to 20 feet. It should be connected to the power service ground electrode. If the length requirement cannot be met you can drive a ground rod, but the ground rod is required to be bonded to the service electrode via # 6 AWG bonding jumper. All this info is contained in 800.40.

Hope this helps.

EDIT: Forgot to add for the RG-6 on your satellite use a device simular to what a CATV company uses. It is a combination grounding and discharge unit or ADU. Its a threaded barrel shaped device. You cut the coax and install male connectors on each cut end and terminate on the ADU. The ADU has either a pigtail or ground terminal to connect to electrode. Do not have a catalog on hand, but any satellite dealer has them or a company called Poly Phaser at

[ February 26, 2003, 03:59 PM: Message edited by: dereckbc ]
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