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Our Community Area is here for Voltimum users to support one another. It is a place to ask questions, seek advice, join in healthy debate but most importantly, learn from each other. Can you help answer the question from a Voltimum user?
Question:
I am working on a project where the contractor has encountered issues with torsion and twisting of armoured cables during install. To the point where the armouring of one of the cables has "birdcaged".
The research I have found states this should be avoided as it can cause damage to the insulation, but I haven't been able to find anything definitive determining the next course of action and havent come across this myself before. The contractor is telling me the manufacturer has only recommended an insulation resistance test, which he has carried out and it has passed. However, I'm concerned that a minor depression/stress on the insulation at this stage, not enough to fail megger testing, but could manifest into something more serious over time, requiring repair/replacement of the offending section (or the whole cable). I'm especially concerned as the cable will run within a space at -23DegC operating temperature (minus 23 - it's a freezer) and it feeds operationally critical equipment.
If a repair were acceptable, it would require 2 joints and new short length of cable, as the damage is in the centre of the run and the ends have been cut to length. Repairs won't be possible when it's cooled down to running temperature, 3M tell me if the joint is made at ambient temperature, the joint will be good to run at those temps once it's gone off.
The specification doesn't capture this scenario, it just refers to manufacturer's recommendations, is there anything else I can refer to in order to determine categorically whether the cable should be replaced or not please - many thanks in advance.
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