144x,
Cable defects that could "pass" routine test...
Conductor water blocking missing or inadequate
Conductor screening tapes incorrect size or type
Conductors screening material fall-in into conductor
Screening material too thin or missing
Conductor screen not bonded or marginal
Conductor screen hang ups due to precuring
Conductor screen material not smooth
Incorrect antioxident levels
Insulation, Poor cross linking
Insulation microvoids
High levels of cross linking by-products
Flow line defects
Contaminants in insulations, solvents, greases, metalic particles
Extrusion surge causing pulse thickness
Wrong insulation screen material
Insulation screen too thin
Insulation repairs attempted in factory
Poor cleanliness when handling materials
Semiconducting pellets fall into insulating pellet boxes
Semiconducting cushioning tapes not used
Extrusion runs too fast causing internal defects
Return conductors not equalised
Foils not sealed
Metallic sheaths to thin or wrong alloy
Corrugations incorrect
Water under metallic sheath caused during oversheathing
Bedding tapes rucked, not overlapped, not compounded
Wrong oversheath type used
Wrong oversheath thickness
Impurities in the oversheath causing localised thinning
Fork lift/crane/mechanical handling damage.
Leaking factory roof or open door during rain onto unprotected insulation.
Lack of adequate semiconducting layer on oversheath
Dispatch reel belly undersize
Dispatch reel with nails into cable
Wooden dispatch reel dries out and is unable to support
cable
No reel or sheath termite protection
Pulling eyes insecure, wrong type used
Inadequate reel protection (wooden battons)
This is a list off the top of my head for XLPE which I am sure others could add to, you would have additional sets for paper lapped, oil/fluid filled, gas, MIND, ppl and epr cables. I can't possibly list every defect that could pass routine test, there are too many. Routine test is a blunt instrument.
Specifications are fine but there is no substitute for inspection with eyes wide open. If you walk round a factory before you buy, inspect during manufacture, inspect after manufacture, witness testing and keep your own records and measurements then you are in a better position to get what you want and to identify what you don't.
The trouble is that few engineers have the time or staff to perform these inspections properly and even fewer have engineers that know what to look for. Being given paperwork is not the sole answer, it requires rigorous checks to be performed.