When does micc short or go bang

[Stevie g]

Micc readings on a 4 core 10 mm are 4 cores to earth 1.09 ohms and between cores 1.70 ohms tested at 500volts cable supplies main DB and off peak DB both backed up by 60 A bs88 fuse, what's the resistance reading likely to be before it goes bang?

 

[Stevie g]

Sorry my bad ,yes Megohms, cable is 40 meters and around 80 years old, old imperial micc,
Thank you all for response
[automerge]1580844854[/automerge]

You're not getting misleading readings from a sub meter on the supply?! Try the heat test mentioned above just behind each seal, easier to see with an analogue insulation meter.

No nothing in between kmf and DB, meters before kmf, analogue do they still make them only joking
Thanks it was periodic, so cross that bridge if we get the repairs

 

[freddo]

As long as the fault is damp in one of the ends (and not pinholes in the sheath) and the sheath hasn't corroded badly, and you can access the ends for repair, it should be repairable. MI cable is amazing stuff.