I will say it gets frustrating with the code contradicting itself.
As this is a large industrial location (refinery) the "insight" rule does not apply as there is a written LOTO policy.
Back on topic, I did find this from the IAEI;
To determine whether raceways and other metal enclosures for signaling use are required to be grounded, we must first determine whether the system is required to be grounded, that is, whether the voltage system is required to include a grounded conductor. This can be determined from 250.20 in most cases (see 250.162 for dc systems). On one hand, according to 250.20(A), most Class 2 systems used for such purposes as doorbells, garage door openers, and thermostats are not required to be grounded because they are less than 50 volts, are derived from grounded 120-volt systems, and are not installed as overhead conductors outside of buildings. On the other hand, a 120-volt, Class 1 circuit would usually have to be grounded in accordance with 250.20(B)(1). Second, according to 250.112(I), the equipment supplied by these circuits is only required to be grounded where system grounding is required by Part II (250.20) or Part VII (250.162). Thus the equipment supplied by or containing the Class 2 circuits in this example is not required to be grounded but the equipment associated with the Class 1 circuits mentioned is required to be grounded. These requirements are reiterated by 250.86, which refers specifically to 250.112(I). The raceway shown in photo 9 is not required to be grounded because it contains only 24-volt Class 2 circuits that are derived from a 120-volt system.
A circuit or equipment that is not required to be grounded by the rules discussed so far in Article 250 may be required to be grounded or bonded in other cases and by other rules. These requirements may be found in Article 725 or in other articles. For example, Section 725.57 imposes additional requirements on Class 2 and Class 3 circuits that extend beyond one building and are subject to accidental contact with higher voltages. In such cases, the Class 2 or Class 3 circuits are required to be treated as communications conductors in certain ways which may include connections to grounded primary protectors and grounding of metallic cable sheaths or shields. In addition, non-current-carrying metal parts of all electrical systems must be bonded in hazardous (classified) locations. Raceways or enclosures may not always be required for signaling circuits in such areas if the circuits are also nonincendive or intrinsically safe, but where metal raceways or enclosures are used in hazardous areas, they must be bonded to comply with Section 250.100.
This article has briefly examined why and how signaling circuits are given special or different treatment in the NEC. The classifications of the circuits covered by Article 725 are determined and differentiated by use and power limitations. Class 2 and Class 3 circuits are most commonly defined by listed power supplies. The inherent power limitations of these supplies justifies the use of alternative wiring methods and different schemes for protecting equipment and persons from the possible hazards of these systems. In fact, in many cases the hazards are already significantly reduced by the nature and sources of the circuits themselves. Article 725 provides somewhat relaxed requirements for installations of signaling circuits. However, in order to maintain the power limitations upon which the relaxed rules are based, requirements for separations from higher-powered circuits and systems must be significantly more restrictive, and these restrictions must be carefully observed.
