Megger Testing a Home

[aelectricalman]

1. The ice storm here in KY caused a power surge on the system. Here are my findings. Did I diagnose this correctly? Do you think it would be wise to Megger it? Here the results:

A. The L1 from the primary blew apart at the connection above the weatherhead. Clean, no burn, just broke away completely severed at the splice.

B. It was dark and the lights were out with the switches off. The only thing to burn where the bulbs that were on. The night lights in the plugs melted in 3 rooms, they were on. The lamp cord burnt in the bedroom.

C. The panel ungrounded buss was burnt on the back of the breakers. All breakers were tripped.

D. The dryer whip where it connects to the dryer was burnt. Cant figure that one out since dryer was off.

E. Still waiting to see what happened to things like fridge, that are always on, and microwave which has lighted led.

After removing all the devices, this is all that is damaged. Do you think a Megger is warranted.

Any opinions , or resources are sought. Thanks for your help.

 

[aelectricalman]

unutilized equipment was untouched. That house had lightning arrestors on it.

 

[don_resqcapt19]

Yes, from your description, you had high voltage on all of the interior wiring. No telling how much hidden damage there is.

 

[76nemo]

You could just as easily perform impedance and load drop on all of the branches. The OCPD's were all taken out. Meggering would be an extra piece of mind, and that's good, but I think it may be over the top.

 

[Lcdrwalker]

I too would vote for the megger. With the condition of the connected cords and equipment, I would say that it is warranted. Also, could the dryer cord be burnt forn a 120V load such as a clock or light?

 

[TOOL_5150]

I would meg the house, and sleep better at night.

~Matt

 

[John Valdes]

Make sure everything is disconnected when using a megger. If it's not burned up yet the megger will finish the job for you.

 

[stew]

don just curious about what you feel the voltage levels could have gotton to? I am not sure how any wiring damage could occur. would not the overcurrent protection yake care of any high current levels or would the lack of a neutral cause them to not trip? maybe i am just tripping myself.

 

[stew]

my bad i forgot op said voltage surge. in that case i would megger also just to be on the safe side.

 

[Pierre C Belarge]

1. The ice storm here in KY caused a power surge on the system. Here are my findings. Did I diagnose this correctly? Do you think it would be wise to Megger it? Here the results:

A. The L1 from the primary blew apart at the connection above the weatherhead. Clean, no burn, just broke away completely severed at the splice.

B. It was dark and the lights were out with the switches off. The only thing to burn where the bulbs that were on. The night lights in the plugs melted in 3 rooms, they were on. The lamp cord burnt in the bedroom.

C. The panel ungrounded buss was burnt on the back of the breakers. All breakers were tripped.

D. The dryer whip where it connects to the dryer was burnt. Cant figure that one out since dryer was off.

E. Still waiting to see what happened to things like fridge, that are always on, and microwave which has lighted led.

After removing all the devices, this is all that is damaged. Do you think a Megger is warranted.

Any opinions , or resources are sought. Thanks for your help.

don just curious about what you feel the voltage levels could have gotton to? I am not sure how any wiring damage could occur. would not the overcurrent protection yake care of any high current levels or would the lack of a neutral cause them to not trip? maybe i am just tripping myself.

What I have highlighted is the tell tale signs that the surge (value unknown) entered the house wiring to the branch circuit level. As Don stated, there is no knowing what the severity of the damage is until a test is completed.

If I were the inspector of record, there would be no cut-in card for the utility company until I was presented with at copy of the documentation of the megger test, including the procedure in which the megger test was performed. Having the EC removing the affected circuitry from the panel, if not the panel replacement as well.
I would request this for the whole house. We have had similar situations with power surges here as described in the OP. The tests always produced results of damaged branch/feeder circuits.

 

[paul]

I would also want to have the breakers tested or replaced if it were me. Replacement would be cheaper and quicker.

 

[iaov]

Absolutely I would Megger this house. It has suffered a high voltage event of some sort and the only way to check hidden wiring for damage is with a Megger. In a past thread mdshunk gives an execellent procedure to follow when Meggering a home.