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Intersystem Bonding Termination

Intersystem bonding termination mounted on a shed

Intersystem Bonding Termination for TV and Telephone

Dear Mr. Electrician: How do I earth ground my telephone and cable TV demarcation terminal blocks? Answer: An easy way is by using an intersystem bonding termination.  Your telephone and cable TV service each needs to be bonded to a ground rod or water pipe ground, or both if available.  This is for lightning protection.  If lightning were to strike the outside cable TV wire and your home has good ground connections, the lightning energy would be channeled directly to earth.  NOTE: Text links below go to applicable products on Amazon.com With a weak or non-existent earth ground connection, the lightning will find a way to earth, but that could be a path through your TV, computer, major appliance, even the metal ducts in your house.  That is how things get damaged or fires start.  Click here for photos of one example of a TV and Telephone bonding and grounding on an older house. Grounding Other Utilities The Photo above depicts an Intersystem Bonding Termination which is required by the National Electrical Code.  This simple terminal block makes it easy for telephone and cable TV installers to connect their grounding electrode conductor wire to a good earth ground connection.  It takes one large grounding electrode conductor and up to four smaller grounding conductors for cable TV and telephone services.  It is important to have this for lightning protection. The Intersystem Bonding Termination is required as per article 250.94 in the National Electrical Code.  You should also read NFPA 780 on lightning protection. A whole house surge protector will add more protection against lightning and power surges.  Some surge protectors can protect additional electrical system threats such as solar flares and an electromagnetic pulse.  Check out EMP Shield electromagnetic pulse and surge protectors (Warning, I am an affiliate). Something else to consider is the installation of a surge protector.  Read my post on that subject here. You should also read my post about the grounding electrode system.
The Telephone and Cable TV Demarcations were Grounded to an Old Pipe

Lightning Protection For TV and Telephone

Dear Mr. Electrician: Can I prevent lightning strikes from doing damage to my house by grounding?  My neighbor was blown out of her chair when lightning hit her TV.  How can I prevent that from happening to me? Answer: There is no 100% full proof method of stopping a lightning strike from doing damage.  However several things can be done to prevent or reduce the damage.  Basically everything electrical needs to be properly grounded and bonded in such a manner as to provide a good direct path for lightning to flow to the earth. The photos below depict an actual job of mine correcting the grounding for a 1940's single family detached house.  Article 250 in the National Electrical Code concerns grounding and bonding.  Some relevant sections are: 250.8, 250.52, 250.90, 250.94, 250.104.  Also read article 800.100 on grounding communication circuits and 820.100 which concerns the grounding of cable TV systems.  NOTE: Some text links below go to applicable products on Amazon.com Lightning Protection for Power, TV, and Telephone The above photo depicts how I found the TV and telephone lines grounded.  It turns out that this pipe was not connected to anything.  It was in the ground only a few inches and contained a piece of cut electrical cable, the remains of which is protruding from the pipe.  Needless to say, this would not be adequate protection if lightning were to strike. The telephone demarcation point and the cable TV demarcation terminal both need to be bonded to the grounding electrode conductor for the main electrical service.  Newer electrical installations have an intersystem bonding termination for the grounding conductor from the telephone and cable TV to connect to. On older houses the telephone and cable TV grounding conductors are sometimes connected to an existing ground rod, or have their own ground rod, or are connected to the grounding electrode conductor. EMP Shield Makes Excellent Surge Devices That Protect From EMI Pulse  Above was the existing ground connection for the cable TV service to the house.  I installed a new #10 copper wire and clamped it to the grounding electrode conductor which was connected to the water pipe inside of the house. The copper wire for grounding TV and telephone must be no smaller than #10 AWG.  #8 wire would probably be too big for most demarcation terminals. Additionally all interior metal piping must be bonded to each other with jumpers around water meters, water filters, and other devices whose removal would interrupt ground continuity. The hot and cold metal water pipes must have a jumper between them.  This is usually done at the water heater.  Although the code requires gas pipes to be bonded, some local areas do not want that.  Best to check with your local building department about bonding the gas pipe. The arrow in the photo above indicates the existing grounding terminal on the original telephone demarcation point.  It was still active with it now being fed from the new outside telephone demarcation box.  The existing ground wire was attached to a water pipe at a sink...
Ground rod with acorn clamp and wire

Install A Grounding Rod

Dear Mr. Electrician: How do I install a grounding rod for my house?  An electrician told me that the electrical service to my house did not have a good ground rod and gave me a ball park price to fix it up.  Why do I need this and what is involved with fixing or installing a grounding rod? Answer: A ground rod is a very important component of the electrical wiring in your home or place of work.  It is part of the grounding electrode system for voltage stabilization and lightning protection.  A ground rod is also referred to as a grounding electrode or anode.  It is required by article 250.53(D)(2) The power company has their power transformer grounded with a ground rod.  If the neutral conductor from the transformer to your house ever got disconnected, the return current would travel through the earth to get back to the transformer.  In addition, when lightning strikes on or around your house the rod creates a path for the high voltage electrical charge to go directly to the earth and avoid causing damage to your home. Whenever you hear of someone's house getting struck and damaged by lightning it is usually because the grounding electrode system was deficient. The grounding electrode system consists of a wire or two that originate on the grounding terminal in your main electrical panel or disconnect switch.  From there the wire(s) will connect to the home's water pipes and to one or more grounding electrodes. The grounding electrodes can be ground rods, concrete encased rebar, copper plates, copper wire in the footings, concrete embedded steel or other means that provide an approved electrical path to earth.  See article 250.52(A) in the national Electrical Code.  NOTE: Text links below go to applicable products on Amazon Protect Against Lightning, Electromagnetic Pulses, Solar Flares, and Power Surges The Grounding Electrode System The main grounding electrode connection for many houses is at the metal water pipe at the point where it enters the home before the water meter.  Look at this area and you should see a copper or aluminum wire; bare, insulated, metal armor jacketed, enclosed in conduit, or taped green.  It should be connected to the water pipe using an approved ground clamp.  The connection should be tight and free of corrosion. The ground clamp in the above photo is attached at the point where the water pipe enters the basement.  An armored grounding conductor requires a ground clamp with an extra clamp on it for the armor to be secured with. If the ground clamp and wire appear corroded or feels loose you should remedy this right away.  A new ground clamp costs only a few dollars and can be purchased at any electrical supply company and at many home improvement stores.  You will also need some emery cloth or sandpaper to clean the pipe. A good precaution when doing this would be to shut off the main circuit breaker or pull the main fuse in your electrical panel.  It is possible that a tiny amount of current...