Very unusual junction box fault

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Believed to have been due to dead spiders and/or other creatures being cremated inside one of the three BT junction boxes. All three boxes destroyed.

Post still smouldering when Fire Brigade arrived but unable to apply water until power cables were isolated.

Power lines NOT involved

Post has to be replaced

.
fire post 30July2019.jpg
 
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think they be more robust to spiders

It is a mystery as to what happened,

This is the top of the pole after it was bought down. It looks like JBs on opposte sides of the pole both caught fire. But given the near hollow state and totally dry state of the pole the fire may have spread through the pole

pole top damage.jpg
 
I find it very hard to believe that a BT line is capable of providing enough current to create the heat needed to start a fire! I know BT lines operate at -48V but the length of the line often means that even the short circuit current is bugger all unless you are nextdoor to the exchange.

I think there is something else at play here. Perhaps mains impressed upon the phone circuits by some other fault? Any lightning in the area within an hour or so?

Where is a our resident former BT engineer? HarryBloomfield, care to comment??
 
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Very strange,i doubt the 50vdc from the phone lines or Ringing voltage would be the culprit hear personally i would be checking the separation distances between phone and overhead power lines,or maybe lightening strike near by.
When i worked for openreach i would occasionally come across boxes that had been frazzled by a near bye lightening strike but you would also get loads of common faults in the local area (internal rectified loops normally) but never anything like that,i did once pick up AC voltage on a exchange frame which was coming from the end users phone line being in contact with mains AC voltage.
 

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