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Intersystem Bonding Termination

Intersystem bonding termination mounted on a shed

Home Lightning Protection

HOW DO I SET UP A HOME LIGHTNING PROTECTION SYSTEM? A home lightning protection system consists of several components.  Good earth grounding through ground rods and water pipes is the most important.  NOTE: Some text links below go to applicable products on Amazon or EBay. Additional home lightning protection components are surge protectors on your main electrical panel, plug-in surge protectors around your home, lightning arrestors on top of your roof, and an intersystem bonding termination for other utilities. Lightning damage may not come from a direct hit to your home, but could be from lightning hitting your cable TV or telephone line at the pole in the street.  Therefore it is important that all utilities in your home be grounded to earth. PROTECTING HOME UTILITIES FROM LIGHTNING An easy way to connect all utilities to earth ground is by using an intersystem bonding termination.  There are several different versions of this available, but they all work the same.  The intersystem bonding termination gets connected to the grounding electrode conductor that goes to the ground rod. Utility companies such as telephone and TV will connect their own grounding conductor for their equipment to be earth grounded.  In the past the utility companies would use a wire clamp to connect to ground wherever they could. With all things connected to earth ground, if lightning were to strike the outside cable TV wire, the lightning energy would be channeled directly to earth. 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 and fires start.  Click here for photos of one example of a TV and Telephone bonding and grounding on an older house. I got a call to check out why a garage door opener in a new house got hit by lightning.  The outlet for the garage door had a functional ground connection.  I looked in the basement at the twin electrical panels and the ground connections looked good there. I checked the water pipe connection and saw that water was coming from a well.  The pipe from the well to the house was plastic and converted to copper once inside.  Lastly I looked for a ground rod and found it.  The wire was on the ground clamp wrong and the clamp was loose. I surmised that due to the poor existing ground connection at the ground rod, the lightning found a good ground path through the garage door rails down to the garage concrete floor, which is a good earth ground.  In the process the garage door opener got in the way. 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 connects one large grounding electrode conductor and up to four smaller grounding conductors for cable...
The Telephone and Cable TV Demarcations were Grounded to an Old Pipe

Grounding TV and Telephone

Dear Mr. Electrician:  What can I do for grounding TV and telephone in my house.  I want to have good lightning protection.  My neighbor was blown out of her chair when lightning hit her TV.  How can I prevent that from happening to me? Answer:  Even with fantastic grounding TV and Telephone there is no 100% full proof method of lightning protection or stopping a lightning strike from doing damage.  NOTE: Some text links below go to applicable products on Amazon or EBay. 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. An excellent book on the subject of lightning protection installations is NFPA 780. 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. LIGHTNING PROTECTION FOR POWER, TV, 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. Click Here to see EMP Shield 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 using water pipe ground clamps with wire 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...
Ground rod with acorn clamp and wire

Grounding Electrode System

Dear Mr. Electrician: How do I install a grounding rod as part of the grounding electrode system for my house?  An electrician told me that the grounding electrode system for my house did not have a good grounding 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:  It is very important to keep the grounding electrode system in your home in good condition.  To install a ground rod some tools and muscle will be needed.  NOTE: Some text links below go to applicable products on EBay, EMP Shield, or Amazon. 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) in the National Electrical Code (NFPA 70). The power company has their power transformer grounded with at least an eight foot grounding 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 home or work place 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. 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...