Bonding prevents fires

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Ravenvalor

Ravenvalor

Senior Member
Location
Triad region of NC
Occupation
Electrician
Hello
If an electrician were to correctly bond all of the metal cold water lines in the crawlspace of an older home (1950s) would that help prevent fires due to lightning and surges?
Thank you
 
No. A direct lightning strike has a massive amount of energy. A lightning protection system (lightning rods and associated equipment) would be more likely to avoid damage from a strike.

Surges don't generally cause fires. They just ruin connected electric devices.
 
Some duct work in a crawlspace got caught on fire during a lightning storm. One scenario of the cause is that maybe a surge came into the crawlspace via the well and then jumped over to some flexible duct work and caught the dust in the duct work to ignite.
 
When you say "properly bond" do you mean to NEC requirements or something over and above that? Things grounded to NEC requirements may still have substantial voltage gradients imposed on them during lightning strikes which could jump to adjacent things, grounded/bonded or not. With the current available in a lightning strike, things bonded to NEC requirements can still be blown apart with arcing.

You could perhaps try to go overboard and bond more with larger wire if looking to prevent a recurrence. But there are no guarantees. If someone is looking for blame because some pipe or duct wasn't bonded, the causality may be hard to prove and even if there was a bonding miss there's no guarantee that having it bonded would have prevented the issue.
 
Yes, bonding can help prevent fires as you describe. A direct lightning strike NO as indicated, but then you have bigger problems. Voltages are induced on on utilities, and communications when there is weather. Bonding all systems together in a building ensures all those systems are equal potential even if elevated in voltage thus reducing or eliminating side flashes between systems as you describe.
 
Ravenvalor said:
Hello
If an electrician were to correctly bond all of the metal cold water lines in the crawlspace of an older home (1950s) would that help prevent fires due to lightning and surges?
Thank you
Click to expand...
All the metal cold water lines...
Wouldn’t once be enough?
someone looking for a payout here or just looking for protection?
If it’s the latter bringing the electrical to code even in a 50s style house couldn’t hurt..
 
Ravenvalor said:
Some duct work in a crawlspace got caught on fire during a lightning storm. One scenario of the cause is that maybe a surge came into the crawlspace via the well and then jumped over to some flexible duct work and caught the dust in the duct work to ignite.
Click to expand...
Or the bonded flexible ductwork arcing to the well. I was replacing a panel many years ago that was located above a bored well on the back porch. The meter was pulled, but the neutral was still connected. As I was routing the service cable, I saw a blue aura coming down the cable, and immediately dropped it on top of the metal well pipe. The HO came running out asking if I was ok. Apparently a lightning strike nearby hit the poco’s line. I didn’t even hear it, but the home owner did.
 
Fires may be caused by lightning side flashes. So bonding helps avoid side flashes and any resultant fires. Both lightning protection outside and surge protection inside the building may be necessary.
 
mikeames said:
Yes, bonding can help prevent fires as you describe. A direct lightning strike NO as indicated, but then you have bigger problems. Voltages are induced on on utilities, and communications when there is weather. Bonding all systems together in a building ensures all those systems are equal potential even if elevated in voltage thus reducing or eliminating side flashes between systems as you describe.
Click to expand...
That is kinda how Chuck Jensen explained it to me. He was/is an engineer for Duke Energy who specialized in lightning research. He would do free walk throughs of my commercial customers' buildings and point out problems. According to him if everything is bonded together then in the event of a surge the voltage goes up and then back down everywhere in the system. However if there is something that is not bonded it will have the highest chance of getting damaged. I picture it as possibly capacitance building up and releasing.
 
Sahib said:
Build up of potential gradient and consequent dielectric breakdown due to passage of lightning current cause a side flash.
Click to expand...
That's a fancy way of saying the voltage gets high enough that it goes through the insulation.
 
mikeames said:
That's a fancy way of saying the voltage gets high enough that it goes through the insulation.
Click to expand...
exactly and is what happens when lightning travels through the sky to get to something on the surface or even just "cloud to cloud" lightning. Voltage got high enough whatever is in the path that is normally considered an insulator allows it to pass though anyway.
 
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