Solid conductors are a single wire per conductor, made for fixed runs and punched down into modules; stranded conductors are many fine wires, made for patch leads that flex. Plugs are made for one or the other and are not interchangeable.
Two constructions of the same cable, each built for a different life, and they are terminated by completely different methods.
Solid: for the parts that never move
Each conductor is a single wire. That gives lower resistance for a given size and better transmission characteristics over distance, and it makes the cable stiff.
Stiffness is a virtue in a wall and a nuisance everywhere else. A solid conductor that is repeatedly flexed will eventually break, often inside the sheath where nothing is visible.
Solid cable is terminated by punching down into an insulation-displacement contact: a keystone module, a patch panel, or a wall outlet. The blades cut through the insulation and grip the wire, and no stripping of individual conductors is needed.
Stranded: for the parts that get moved
Each conductor is a bundle of fine wires. That makes the cable flexible and tolerant of being coiled, trodden on and pulled around the back of a desk, at the cost of higher resistance for the same size and shorter useful distance.
Stranded cable is what patch leads are made from, and it is terminated with a crimped plug rather than punched down.
The plugs are not interchangeable
This is the part that catches people out. The contacts inside an eight-position modular plug are shaped differently for the two conductor types: one design is meant to pierce a single solid wire, the other to fold around and grip a bundle.
Using the wrong plug produces a joint that may pass a continuity test on the day it is made and fail intermittently months later, under load or when the lead is moved. Plug packaging states which conductor type it is for, and plugs specified for both exist and say so.
Where each belongs in a real installation
Solid for the horizontal run: from the cabinet to the wall outlet, terminated onto a patch panel at one end and a keystone module at the other.
Stranded for both ends of that channel: the lead from the patch panel to the switch, and the lead from the wall outlet to the device.
That is the arrangement the standards assume when they divide a hundred-metre channel into ninety metres of fixed cable plus ten metres of leads — and the ten metres are stranded precisely because they are the parts that get moved.
Two consequences worth knowing
Power over Ethernet puts current down the conductors, and resistance produces heat and loss. A long stranded lead is a poorer choice for a powered link than a solid run of the same length, and it is one more reason the standards separate the two.
Buying a drum means buying solid, and buying leads means buying stranded, so most people never make the choice consciously. It becomes a decision only when someone crimps plugs onto the end of a drum of solid cable to save fitting a module — which is exactly the case where the plug type has to be right.
The questions that come up before an order
What happens if I crimp a plug made for stranded onto solid cable?
The contact geometry is wrong for the conductor, and the result is a connection that may test fine on the day and fail intermittently later — the worst kind of fault to chase. Plug packaging states which conductor type it is for, and some plugs are specified for both.
Can I use a long patch lead instead of running solid cable?
It will work, and it is worse in two ways: stranded conductors have higher resistance for the same size, which matters on a long run and matters more if power is being carried, and a patch lead is not built to sit in a wall. For anything permanent, solid cable terminated onto modules is the arrangement.
Last reviewed 10 September 2026