They are blaming this on a PV installation

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five.five-six

Senior Member
Location
california
In the video, you can still see the, to be unnamed, PV installation contractor’s yellow truck in front of the house.

It hits kinda close to home because a good friend of mine is a SoCal Gas supervisor that works in the area, he’s OK but saw the fire.

For the life of me, I can’t think of how you would accidentally damage a gas line on a PV installation in a modern home. I don’t think it was the PV installers, but that’s what all the news is saying and that’s what my gas Co buddy told me.

https://losangeles.cbslocal.com/2019/07/15/explosion-house-fire-reported-in-murrieta-neighborhood/
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Seems like we should not jump to conclusions. If they were 'renovating the home' there could have been multiple contractors working on it.
 

five.five-six

Senior Member
Location
california
busted!

~RJ~


I don’t see any reason for a PV contractor to be trenching on a SFR like that. I think it has to be some other contractor. Also, I don’t see how a rupture outside would cause the house to explode, which it did.

Gas pipe is mostly black pipe or galv... you really have to want to cut that stuff to get through it.

In other videos, you can see the roofing tiles were knocked out of place on adjacent homes by the force of the blast.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
In the video, you can still see the, to be unnamed, PV installation contractor’s yellow truck in front of the house.

It hits kinda close to home because a good friend of mine is a SoCal Gas supervisor that works in the area, he’s OK but saw the fire.

For the life of me, I can’t think of how you would accidentally damage a gas line on a PV installation in a modern home. I don’t think it was the PV installers, but that’s what all the news is saying and that’s what my gas Co buddy told me.

https://losangeles.cbslocal.com/2019/07/15/explosion-house-fire-reported-in-murrieta-neighborhood/


"[FONT=Lato, Arial, sans-serif]According to a neighbor, the family bought the home two months ago and were in the process of renovating it."[/FONT]

[FONT=Lato, Arial, sans-serif]well, unless it was underground PV's, i don't see the need for trenching.

UNLESS it was a PV array remote from
[/FONT][FONT=Lato, Arial, sans-serif]the house, on the side of a hill, or something like that,
[/FONT]and there was a conduit to tie it to the panel.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
The one mistake I could imagine a PV contractor making on a simple install is driving a ground rod in the wrong place. But I hasten to add that is 110% speculation on my part with respect to this incident.
 

five.five-six

Senior Member
Location
california
My buddy at the gas Co. says they were driving a ground rod and damaged the gas main, which doesn’t make any sense to me.

first, I bet that house has a ufer

2nd, unless you dead nuts center punched the pipe, the rod would bounce and go around

3rd, even if you did dead nuts center punch the gas line, how hard do you have to drive it to get it to puncture a gas main

last, if it was punctured outside, why would the gas go into the house?


something fishy.
 

kwired

Electron manager
Location
NE Nebraska
There have been many incidents in the past where an outside/underground gas line was damaged in some way and gas finds a way into a building and causes explosion incident.

That gas can follow the trench path it is installed in, especially if the back fill is less compacted than surrounding soil, then that is one easier path to follow. The gas line may emerge from ground outside a building, but there may be other penetrations into the building from below ground that it may find a way into.

Non metallic underground gas piping is becoming more common, one could drive a ground rod through that easier than through old steel gas piping. Old steel gas piping can still be damaged by glancing a ground rod off of it. May not cause a leak immediately, but can damage protective coatings and allow for corrosion of the steel and a leakage incident to occur sometime down the road.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
In the video, you can still see the, to be unnamed, PV installation contractor’s yellow truck in front of the house.

It hits kinda close to home because a good friend of mine is a SoCal Gas supervisor that works in the area, he’s OK but saw the fire.

For the life of me, I can’t think of how you would accidentally damage a gas line on a PV installation in a modern home. I don’t think it was the PV installers, but that’s what all the news is saying and that’s what my gas Co buddy told me.

https://losangeles.cbslocal.com/2019/07/15/explosion-house-fire-reported-in-murrieta-neighborhood/

I didn't watch the video but the text of the article does not mention PV or a PV contractor.

While household gas lines are usually (always?) metal, gas mains are very often plastic. The ones I have seen have a metal wire running along the top of them to make them more easily detectable. They are usually buried more deeply than one would trench for a PV installation if such a thing were to be done. That said, in my experience trenching for PV installations in residential neighborhoods is pretty rare.
 

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
It would be unlikely, but perhaps the ground rod hit a plastic gas pipe at or near a "cross bore" with a sewer pipe (i.e., penetration or damage of the sewer pipe by directional drilling when the gas pipe was installed):
https://callbeforeyouclear.com/

That would have provided an entry point into the house through the drain and waste system.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
After reiterating that all of this is speculation, and may have no relevance to the actual incident...

I can think of two reasons (other than pure incompetence) why someone might be driving a ground rod on a house that has a UFER.
The first is that some inspectors don't accept that you have a valid UFER if you can't see where it goes into the concrete or if you can't provide a permit record of it having been originally approved by an inspector.
The second is 690.47(D) in the 2016 California Electric Code (based on 2014 NEC). This is a stupid requirement that has been removed (as a requirement) from the 2017 NEC, thank goodness. But it's still current in California and if the AHJ were enforcing it there... Well, if that was the reason they were driving a ground rod and the reason they breached the gas, that would just be absolutely tragic.

In firm dirt I don't imagine that a ground rod down 21" would necessarily deflect. If the gas pipe were not in the greatest shape or if the person driving it were stupid enough to just keep wailing on it then I could see it still causing damage. You have to cognizant of where you're driving rods.

Nobody calls 811 before driving a ground rod. They wouldn't be able to give you precise enough information anyway. We all just have to use our heads and live with the fact that if this were to happen to us the lawyers will screw us.
 
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