residential near miss

[JPLocal]

older 60 amp fused residential service . Frayed service entrance conductors in rigid . Ungrounded conductor shorted to service conduit or grounded conductor . Grounding electrode conductor not securely attached to water service . Romex and Bx (armored cable) original @ 70 years old. Some bx burnt completely through in contact with cast iron sewer pipe .Arcing at Romex grounding conductor where terminated in a few junction boxes that I opened . Arcing around any loose terminations at panel . Neutral conductor also melted inside one emt run. Installed new service. Owner said panel was arcing like crazy before conductors burnt through at mast. Checked continuity between cable conductors . Plan on using megohmmeter on existing bx to see if reuse possible. Plan to open all bx junctions to visually inspect . Is that adequate ? I feel that the romex is toast .Any thoughts on other safety methods to proceed with ? Want to do a good job and sleep at night .Two story house . JPLocal

 

[petersonra]

at 70 YO, it is probably time to consider replacement.

 

[Ponchik]

I agree with the peterson.

 

[gadfly56]

The insurance company should not balk at a compelte re-wire. If they seem resistant, ask them to sign a waiver regarding the reuse of existing cable where it appears undamaged. This will tend to loosen the purse strings.

 

[ptonsparky]

The Insurance company should not balk at a compelte re-wire. If they seem resistant, ask them to sign a waiver regarding the reuse of existing cable where it appears undamaged. This will tend to loosen the purse strings.

I do not see a reference to Insurance company in the OP.

 

[GoldDigger]

I do not see a reference to Insurance company in the OP.

Since the fault was in service conductors on the POCO side of the service point, there may be reimbursement from POCO? If not, then homeowners insurance, if any, should apply.

 

[gadfly56]

I do not see a reference to Insurance company in the OP.

True enough, I may have gotten a little ahead of the game with that assumption. Typically, this sort of thing has "insurance claim" written all over it. If the home was occupied at the time of the incident, odds are good that it isn't today, or at least it shouldn't be. I can't imagine that any service is still active, and the local FD and building department are unlikely to allow continued habitation.

 

[starbolin]

o...Plan on using megohmmeter on existing bx to see if reuse possible. Plan to open all bx junctions to visually inspect . Is that adequate ? I feel that the romex is toast .Any thoughts on other safety methods to proceed with ? Want to do a good job and sleep at night .Two story house . JPLocal

A megger is a tool for you the EC to use in telling you where to look. It cannot tell you a cable is good. It only suggests when one is bad. Don't lean on your equipment make your decisions for you. You are the expert on the site. You state your opinion that the NM is toast. Your license from the state makes that opinion enforceable. Time to step up and make the big decision: do you shut down the site? From the history you've given one could be certain there is other damage that is hidden and that you would just looking for damage that you already know is there.

If you want to spread the liability around then that is what consultants and PEs are for.

 

[starbolin]

... Arcing around any loose terminations at panel . Neutral conductor also melted inside one emt run.

That's something more that just frayed cables and loose wires. Sounds like an open neutral from the POCO and some really high differential. Do you have a theory as to the cause of the arcing?

Installed new service.

I missed that the first time. Did you install the new service? Are there breakers in the panel.? Is there still and open permit? I assume all the questionable NM is not powered yet? What is the scope of the original work?

Owner said panel was arcing like crazy before conductors burnt through at mast.

Hard to say what the danger is without a cause as to the original damage. Was all this from one shorted conduit run or was there an unbonded neutral at some time?

Checked continuity between cable conductors . Plan on using megohmmeter on existing bx to see if reuse possible. Plan to open all bx junctions to visually inspect . Is that adequate ?

What was the cause of the arcing? Was there overvoltage? Why did the OCPD not clear the fault? What kind of construction, balloon, stick, slab etc? Is the romex the more troublesome rubber covered conductors stuff?

I feel that the romex is toast. Any thoughts on other safety methods to proceed with ? Want to do a good job and sleep at night .Two story house . JPLocal

Were you to decide on a R&R ( not my choice ) I would recommend removal of anything and everything that looked in any way suspicious. The is already evidence of hidden damage. Very hard to be 100% sure now.

 

[John120/240]

The insurance company should not balk at a compelte re-wire. If they seem resistant, ask them to sign a waiver regarding the reuse of existing cable where it appears undamaged. This will tend to loosen the purse strings.

I do not see a reference to Insurance company in the OP.

Have the homeowners contact their insurance carrier, then you thru the homeowner state your case being the Electrical Professional you are.