Should metal chimney liners be grounded against lightning strikes?

Can't hurt.

Put up a lightning rod, which doesn't ground anything, to discourage lightning in the first place.

lightning rods dont discourage lightning they just give it a safe path to ground minimizing building damage ....

I would ground the chimeny liner

I would put a lightning rod on top of the chimney and run a wire down to a rod below.

If you ground it, don't compromise the integrity of the liner by drilling a screw hole. Liners are usually stainless steel and hard to drill through, that's a good thing. Use a clamp. Drilling through the liner MAY create a small leak where heat can escape causing a fire.

Hank

We are on a slight ridge but there are many tall trees around. I hope trees make a good path to ground? I was thinking of installing an external TV antenna which would force me to ground it. I guess the liners could be tied in as well.

I guess I should talk to our insurer.

Thank you all for your help!

If you ground a metal liner you will just attract the lightening, something you don't want. If lightening will blow the bricks off a chimney which is not a conductor, I don't think lightening cares where it strikes. If you ground it and it attracts lightening it could still blow the top of your chimney off. A higher lightening rod may attract it instead, (may). It's not an exact science.

If you ground a metal liner you will just attract the lightening, something you don't want. If lightening will blow the bricks off a chimney which is not a conductor, I don't think lightening cares where it strikes. If you ground it and it attracts lightening it could still blow the top of your chimney off. A higher lightening rod may attract it instead, (may). It's not an exact science.

HeyBub wrote:

Following that theory, I guess we should remove grounding from roof mounted TV antennas and cable dishes too.

I agree that if you want protection add a lightning rod. The earthing system for a ground rod has to be tied to the earthing system of the electrical system. For most of us the probability of being hit is quite low.

Ordinary antennas are not earthed to protect from lightning strikes - the earthing system is not heavy enough. Hams may expect their much more extensive antennas to be struck by lightning, which requires a more extensive earthing system.

Earthing an antenna (or flue) will not attract lightning. As haller wrote a lightning rod is just a safe point for lightning to strike.

This is NOT correct...

Mark

Tell that to my friend who lost his house when the installers put a screw thru the lining. Also, when a chimney, esp. metal ones, build up creosote and catch fire, they get really really hot. Ever seen one on fire? I have seen quite a few since I am a retired firefighter of 28 years. They get red hot and sound like a jet engine.

If you put screws thru the liner, you did it wrong.

Hank

I'd say it all depends on what kind of chimney liner it is and what it's used for. A chimney liner for a fireplace is a very different application than one for a gas water heater. And a chimney liner relies on the existing chimney for thermal protection, does it not? I don't see how a sheetmetal screw through the end of a gas water heater chimney liner is going to result in something bad happening. Put a screw through a class A steel chimney for a fireplace and it could be very different.

I was talking about a WOODBURNING fireplace chimney that is not inside a masonry chimney. Most of the new houses today have metal chimneys inside a wood structure. The metal chimney is supported by straps. A have seen installers put screws in the chimney and make their own straps when the attached standard strapping isn't in the same place as the wooden frame work. Even masonry chimneys build up creosote and catch fire. And if there is a crack in the masonry, it can cause structual damage.

Hank

Lightening is what Michael Jackson did to his face. Lightning is what happens when clouds build up dissimilar charges and there is a giant spark between the clouds or between the coulds and the earth.

Hi, If you worry about it, how about eaves trough? Too many things to ground around the house. We are always exposed to lightning, if got hit direct, nothing much will withstand no matter what.

And it could enlighten you.

I never could spell any word correctly more than 2 times.