Two datasheets, two brands, same size of cable — and the numbers don’t quite match. Which one is wrong? Usually neither. Datasheets mostly differ because of what each row actually means, and a buyer who can read them line by line compares cables instead of comparing fonts.
Construction. The one-line description — conductor material, insulation, bedding, armour, sheath — is the cable’s identity. Every other row depends on it, so check it first against what you actually intend to buy.
Conductor class. Class 1 is solid, class 2 stranded, classes 5 and 6 flexible. This decides how the cable handles, terminates and routes; our conductor class chart explains the four classes. A datasheet that doesn’t state the class is already being vague with you.
Maximum DC resistance at 20 °C. The most honest number on the page, because it’s fixed by IS 8130 for each size and class and can be verified with an instrument. Compare it against the standard, not against the other brand.
Insulation and sheath thickness. Standards specify these as nominal values with a permitted minimum at any point. A datasheet quoting only “nominal” is normal; what you’re entitled to expect is compliance with the standard named at the top of the sheet.
Overall diameter and weight. Not vanity figures — OD sizes your glands, conduits and duct fill, and weight drives drum handling and tray loading. ODs carry a tolerance, so glands are sized on measured cable, not the catalogue.
Current rating. The trap row. A rating is only meaningful with its conditions — ambient temperature, method of installation, grouping. Two brands quoting different amps for the same cable are usually quoting different conditions. Bring both back to your installation using the derating factors guide before believing either.
Packing. Standard drum lengths, and whether non-standard lengths attract a premium or a wait. On a control cable with dozens of cores, drum length also decides how many joints your route needs — sometimes the cheapest cable per metre is the most expensive per route.
Read this way, a datasheet stops being a formality and becomes the contract it was always meant to be: a set of claims, each one checkable.