Introduction: Solid and Stranded UTP
UTP twisted pair comes in two conductor constructions: Solid — a single solid copper wire conductor, and Stranded — a multi-strand conductor twisted from several thin wires. The difference between them determines where the cable will be laid: permanently in a wall or as a flexible patch cord from an outlet to a computer. The TIA/EIA-568-B.2 standard clearly distinguishes these two types: Solid is intended for permanent links of the horizontal subsystem, Stranded — for patch cords.
Solid UTP is stiffer, holds its shape better and has lower attenuation over long distances. Stranded UTP is flexible, withstands multiple bends, but introduces slightly higher resistance and is not designed for long distances. Both types are manufactured in category 5e and higher, with 2 or 4 pairs, in copper construction, including shielded F/UTP. For a general overview of categories and twisted pair design, read the guide about UTP cable.
Comparative Table of Solid and Stranded
| Parameter | Solid UTP (Solid) | Stranded UTP (Stranded) |
| Conductor design | Solid copper wire 22–26 AWG (most often 24 AWG) | Bundle of 7 or 19 thin copper wires of the same total cross-section |
| Flexibility | Low, rigid, does not like frequent bending | High, elastic, withstands multiple bends |
| Bending radius | Not less than 4 cable diameters; if exceeded, the conductor may break | Not less than 4 diameters, but in practice more flexible |
| Signal attenuation | Lower, smaller linear resistance | Slightly higher, the difference is noticeable on lengths over 50 metres |
| Maximum length of permanent link | 90 metres according to TIA/EIA-568 | Not standardized; recommended up to 20–30 metres for patch cords |
| PoE support | Excellent, low resistance reduces heating | Acceptable on short patch cords; for long runs ineffective due to higher resistance |
| Type of crimp connectors | IDC insulation-displacement contacts for outlets and patch panels; for plugs — connectors with reinforced blades | RJ-45 plugs with pointed contacts that penetrate between the strands without breaking them |
| Connection to an IDC outlet | Ideal: the rigid conductor is reliably fixed by the insulation-displacement contact | Prohibited: the thin strands are not cut through, the contact is unreliable, breakage is possible |
| Mechanical durability | Sensitive to vibration, may develop microcracks with multiple bends | Resistant to vibration and frequent movement |
| Cost (per metre) | Comparable or slightly lower than stranded | Comparable or slightly higher due to more complex production |
| Typical application | Horizontal permanent wiring, backbones laid in trays, above suspended ceilings | Patch cords, equipment cords, camera connections, temporary lines |
Conductor Design and Flexibility
The solid conductor is a monolithic copper wire of 24 AWG gauge with a diameter of about 0.51 mm. Such a conductor holds its shape perfectly, which is convenient for laying in cable ducts and fixing on IDC frames. However, with frequent bending, the solid metal fatigues: microcracks appear, which increase resistance and eventually destroy the conductor. Therefore, solid UTP is not intended for moving sections.
Stranded UTP is twisted from seven or nineteen thin copper strands, forming a flexible conductor of the same nominal cross-section. Such a cable bends easily without breaking and withstands thousands of bending cycles. But precisely because of the multi-wire structure, it has a slightly higher linear resistance and tends to fray when terminated in an inappropriate connector. Flexible UTP is indispensable for patch cords, where mobility and frequent re-patching are required.
Electrical Characteristics over Length
The difference in resistance between Solid and Stranded is small — about 5–10% in favour of the solid conductor. Over short distances up to 20 metres, this does not affect the signal quality. However, at the maximum length of the permanent link of 90 metres established by the TIA/EIA-568 standard for Cat5e and Cat6, the attenuation of the stranded cable exceeds the permissible limits. That is why the standard requires the horizontal cable to be exclusively solid.
For PoE power transmission, the increased resistance of the stranded conductor leads to additional losses and heating. On a short patch cord of 1–2 metres, the effect is negligible, but laying Stranded between floors and supplying 30 W through it is unacceptable. For the same reason, solid cable is preferable for IP cameras over long distances. More about power supply and shielding — in the comparison FTP or UTP.
Installation Features, Connectors and IDC
Solid UTP is ideally terminated in outlets and patch panels with IDC contacts. The blade contact reliably cuts into the solid copper, providing a gas-tight connection. For termination with an RJ-45 plug, connectors with reinforced blades are needed. When using ordinary plugs, the contact may be incomplete — Solid is more rigid, and the blade sometimes only slides across the surface.
Stranded UTP requires plugs with pointed contacts that penetrate between the thin strands without cutting them. It is absolutely forbidden to insert stranded wire into an IDC outlet: the thin strands are not cut through by the insulation, they spring back and do not ensure stable contact, and over time they oxidize and loosen. The laying rules with standards are disclosed in the article UTP installation.
When Solid UTP Is Needed
- Horizontal SCS wiring: from the patch panel to the outlet at the workplace. A route of up to 90 metres of a permanent link.
- Cables inside walls, above the ceiling, in trays and ducts, where mechanical stability and low attenuation are important.
- Backbone lines inside a building for gigabit and 10‑gigabit applications.
- Video surveillance systems with long runs, PoE power over distance.
- Facilities requiring SCS certification, where the tester checks the permanent link — it must be on Solid.
When Stranded UTP Is Needed
- Patch cords and equipment cords of any length, from 0.5 to 20 metres. They provide flexibility and convenience at the workplace.
- Connecting equipment inside a rack: from the patch panel to the switch, from the server to the outlet.
- Temporary networks at events, where the cable is constantly moved and coiled.
- Lines to moving objects: PTZ cameras, trolleys, test benches.
- Home connections from an outlet to a PC or TV, if a ready-made patch cord 3–5 metres long solves the task.
Typical Mistakes in Selection and Crimping
- Crimping stranded UTP into an IDC outlet. The contact is unstable, the cable loosens over time, the network works intermittently.
- Using solid UTP for patch cords. After a dozen bends, the conductor breaks inside the sheath, the link disappears.
- Laying stranded cable in a wall over a length of more than 30 metres. Attenuation exceeds the norm, the speed drops, the line is not certified.
- Terminating solid UTP with plugs for stranded cable. The connector blades are not designed for a solid conductor and may not provide reliable contact.
- Laying a solid cable without a length reserve near moving equipment. Tension and vibration lead to breakage.
- Choosing stranded UTP for an outdoor IP camera at a distance of 60 metres. Losses in PoE and signal make the line unstable.
Frequently Asked Questions
How to distinguish solid UTP from stranded?
By marking: Solid or the letter “S” — solid, Stranded or “St” — stranded. Physically, stranded is softer and bends easily with fingers; when stripping, the conductors fluff up into a brush. Solid holds its shape; if you try to bend a sharp corner, it may break.
Can stranded UTP be used for internet in an apartment?
For a short patch cord from the outlet to the router — yes. But for wiring from the low-current panel to the outlet, a solid cable laid permanently is required.
Which cable is better for PoE: Solid or Stranded?
Definitely Solid. Lower resistance reduces losses and heating. Stranded is acceptable only on short patch cords up to 5 metres.
Does the conductor design affect the connection speed?
Over short distances, no. Over a length of more than 50 metres, stranded UTP may not provide gigabit speed due to increased attenuation. According to the standard, the horizontal line is always solid.
What to choose for video surveillance: solid or stranded UTP?
For a fixed camera mounted on a wall and a run over 20 metres — solid. For a PTZ camera with a moving connection — a flexible stranded patch cord on the final section.
Which cable to lay in an office: Solid or Stranded?
Into walls, above the ceiling, into trays — only solid. At the workplace from the outlet to the computer — a ready-made stranded patch cord. This combination complies with SCS standards. About the differences between categories, read the article Cat 5e or Cat6.
Conclusion
Solid and stranded UTP do not compete, but complement each other. Solid — for permanent horizontal wiring, Stranded — for flexible patch cords. An attempt to substitute one for the other leads either to breakage of the rigid cable on a moving section, or to unstable contact and attenuation on a long run. Observance of this simple rule, enshrined in TIA/EIA-568, guarantees reliable network operation for decades. You can select solid and stranded UTP, including shielded F/UTP, 2‑pair and 4‑pair, category 5e and higher, in the catalogue stranded UTP.
