It’s easy to become a Suspicious Cat when inspecting ethernet cables. You might pick up two CAT5e cables and notice something odd: the twist rate of the internal wires seems different. One might look tightly wound, while the other appears more relaxed. Does this mean one of them isn’t truly CAT5e? The answer, surprisingly, is no. When it comes to category ratings for network cables, performance is king, not just construction aesthetics.
Category ratings, like CAT5e, are primarily based on how well a cable performs, not precisely how it’s built. As long as a cable meets the stringent performance benchmarks set for CAT5e, it earns that classification, regardless of variations in its physical construction, such as twist rate.
Why the twist rate differences then? Manufacturers sometimes use the same machinery for producing different categories like CAT5e and CAT6. CAT6 cables often utilize thicker 23 AWG wire compared to the 24 AWG wire common in CAT5e, and they generally have a tighter twist. To streamline production, a manufacturer might use their CAT6 machinery to also produce CAT5e. This can result in a CAT5e cable exhibiting a higher twist rate, more akin to what you’d expect in a CAT6 cable. Despite this, if it achieves CAT5e performance levels, it is still correctly classified as CAT5e.
Looking closely at cables, one might even label a seemingly loosely twisted CAT5e as the “suspicious cat 5E” and another, more tightly twisted one as “Definitely CAT 5E”. However, this visual assessment can be misleading. The cable that looks “suspicious” might very well be perfectly compliant with CAT5e standards.
It’s also important to note that within a cable, each pair of wires should have a different twist rate. If you strip back the cable jacket, you’ll observe varying twist densities in each pair. This deliberate design is crucial for minimizing crosstalk, the interference between cable pairs. Different twist rates enhance common-mode rejection, effectively reducing signal leakage and ensuring cleaner data transmission.
In conclusion, don’t let visual inspections make you a suspicious cat doubting your cable. You cannot reliably determine the category of a UTP cable merely by looking at its construction, including its twist rate. Category ratings are about verified performance. As long as the cable delivers CAT5e-level performance, the twist rate, and other construction variations, are secondary.
Reference: https://community.cedia.net/blogs/david-meyer/2019/09/16/category-cable-twist-rate
