How to Install Whole-House Lightning Protection | Ask This Old House

Meteorologist Jim Cantore discusses lightning with Ask This Old House host Kevin O’Connor. Then landscape contractor Roger Cook travels to central Florida to install a lightning protection system.

Lightning protection systems like the one in this video should be installed by an expert contractor.

About Ask This Old House TV:
Homeowners have a virtual truckload of questions for us on smaller projects, and we're ready to answer. Ask This Old House solves the steady stream of home improvement problems faced by our viewers—and we make house calls! Ask This Old House features some familiar faces from This Old House, including Kevin O'Connor, general contractor Tom Silva, plumbing and heating expert Richard Trethewey, and landscape contractor Roger Cook.

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How to Install Whole-House Lightning Protection | Ask This Old House

[thomascleary]

rip rodger thank you for the great advice we will all miss you

[waryaamoxamad]

These guys are good! I don't even own a house, but still watch all their shows. concise, clearly explained and professionally done.

[Maxid]

This is obviously a real problem. Did you notice the people with the most experience with lightning didn't have any hair on their heads?

[DC-cglj]

Very interesting idea to place the cabling inside the attic. Question - should a lightning strike occur, will the electricity passing through the cabling in the attic make a fire more susceptible with burning or charring the wood frame work?

[smashcutlass]

Like the lightning expert with the cute little aluminum ladder

[j.j.loehriii]

A lot of people freaking out about the conductor being run inside the house.  Let me see if I can explain this so it makes sense.  The copper conductor is just that - a conductor.  It is LOW RESISTANCE which means the current from the strike can pass along it quickly and without any resistance.  Resistance is what brings the heat.  Ever see a tree that has been struck by lightning?  The lightning uses the tree as a conductor to ground.  Wood is HIGH RESISTANCE.  The current has to really work to follow that wood to the earth and in the process it heats it up and strips the bark.  If conductor that was LOW RESISTANCE was in that tree and tied to a ground rod, you wouldn't see any heat build up or damage to the tree.  Once lightning gets to permanent moisture in the earth---it dissipates...-This lightning protection system is a continuous circuit from earth ground (the bottom of the ground rod about 10' below grade) up to the tip of the air terminal about 12" above the structure.  Earth potential is brought up to the tip of that air terminal above the structure.  Tests involving rockets which can create lightning strikes have been conducted and the point of dissipation (aka as a "return stroke leader") from the air terminal to the cloud induced lightning charge is well above the structure.  Steel framed skyscrapers get struck by lightning all the time.  These buildings have lightning protection systems which utilize the steel framework as the conductor.  The roof air terminals are tied to the steel at roof level and the steel is grounded at 60' intervals around the perimeter of the base of the steel.  These buildings don't heat up and the steel doesn't melt etc when lightning strikes because steel is considered acceptable as a LOW RESISTANCE conductor.  Underwriter's Laboratories and the National Fire Protection Association have standards for lightning protection and they all concur that internal conductors are acceptable.

[johnbaptist]

There is no words for you all how awesome you are 😍 . May be supper awesome . I have leaned a lot from your program ❤ . It is always a great pleasure when I learn a lots of good advise & lessons. My LORD be with U all
Thanks

[rasimon]

Key step left out of the video which is bonding the building / structure grounding electrode as per NEC 250.106. Basically run as least #6 bonding cable to the building ground rod from the lighting protection system ground

[ckac]

I wish they had spent much more time talking about the indirect strikes and the surge protection options they used. Or is there another video about that ?

[wbmgr]

This system is designed to dissipate charge to prevent a strike, not absorb a strike as many who have posted below believe.

The purpose of an air terminal is to continually bleed off the static charge in the immediate area around the structure to avoid the likelihood of a strike in that area. The sharp point of The aerial is by design for that purpose.

An in ground low impedance ground system bonded to the service entrance ground would serve a different purpose allowing a surge from the incoming line (much more likely) possibly from a lightning strike nearby or an EMP created by a strike in the immediate area which was absorbed into the power lines and entered the structure as a surge.

This is why a whole panel surge arrestor on your main service entrance (outside the building) is so important. A secondary whole panel unit on each sub panel in your home is a great idea... but the primary outdoor unit is the most important. Having it located OUTSIDE is the key. You want to dissipate the surge before it enters the building.

Everything be bonded back to the service entrance ground and nowhere else, and that the neutral/ground bond only exist at the service entrance panel. Otherwise you will always have electrical issues and noise on your power lines.

[bobnon]

I live in Orlando and the lightning is real!

[MisterTee]

I've seen lightning storms a few times myself here in Saskatchewan, Canada in the winter.

[hotwax]

We used to have a single tall lightning rod on our roof, but now I want this.

[kobelcofan]

Am I the only one who wonders why they sent Rodger out for this and not tommy or Kevin?

[ekujj]

They’re only doing that so Marty can get back to the future. 1.21 Jigawatts

[pritam]

Great. 👍✌🌷🙋‍♂️😊 you western countries peoples are very professional & technocratic- nice vdo. Clear voice.

[twc]

They installed a copper lightning rod with a brass fitting onto a steel thread rod, then to copper cable and finally to copper rods. Aren't they adding a lot of resistance with the brass fitting and steel thread rod? Will those dissimilar metals cause corrosion?

[spuddy_bud]

I have a main panelboard which includes the meter and the main disconnect for 200 amps. This box has room for only 8 breakers but also has pass-thru lugs at the bottom of the box. These pass-thru lugs carry power (200 amps) to a subpanel. The main panelboard as well as the subpanel are Square D. Do I install the whole house surge protector in the main panelboard or the subpanel or both. Please advise.

[powertech]

Definitely it is very good for Home protection from Lighting.

[AiBilly]

If you want to skip the "How Lightning happens" mumbo jumbo and get to "How to protect your home" skip to 4:25