That does not even make sense. Depending on the voltage and current of the circuit, it would be a class 2 or class 3 circuit.

If you use "CL-3" (class 3) cable, it is within spec for either application.
The cable itself is not derated if the circuit is within the boundaries of class 2.

Since you obviously too busy to research what should be basic knowledge to CIs, let me go out of my way to find it and present it to you.

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Class 2 circuits.
Class 2 circuits typically include wiring for low-energy (100VA or less), low-voltage (under 30V) loads such as low-voltage lighting, thermostats, PLCs, security systems, and limited-energy voice, intercom, sound, and public address systems. You can also use them for twisted-pair or coaxial local area networks (LAN) [725.41(A)(4)].

Class 2 circuits protect against electrical fires by limiting the power to 100VA for circuits that operate at 30V or less, and 0.5VA for circuits between 30V and 150V. You protect against electric shock by limiting the current of the circuit to 5mA or less for circuits between 30V and 150V [Chapter 9, Table 11].

You can wire Class 2 circuits with Class 2 cable or any of its substitutes permitted by Table 725.61(A), depending on the condition of use.

Class 3 circuits.
Use Class 3 circuits when the power demand for circuits over 30V exceeds 0.5VA, but is not more than 100VA [Chapter 9, Table 11]. We often use Class 3 signaling circuits for security systems and public address systems; voice, intercom, and sound systems; and some nurse call systems.

Higher levels of voltage and current are permitted for Class 3 circuits (in contrast to Class 2 circuits). To prevent an electric shock hazard, the wiring must be rated no less than 300V [725.71(E) and (F)]. Wiring methods that meet this requirement include PLTC Cable, Class 3 Cable, or any of its permitted substitutions listed in Table 725.61(A), depending on the condition of use.

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So here you see the full definition of Class 2 and Class 3 circuits, and the recommendations for cabling for these applications.

(note that the handoff is at 30v, not 50v as I previously posted)

Hope this clarifies things.