Are all machines in US required to have a UL certification?

OSHA’s Nationally Recognized Testing Laboratory (NRTL) Program recognizes private sector organizations, such as Underwriter Laboratories (UL), to perform certification for certain products to ensure that they meet the requirements of both the construction and general industry OSHA electrical standards.

Thirty-seven items need NRTL certification. Otherwise, anything not on the list can be certified independently by the manufacturer itself. NRTLs are third-party (i.e., independent) organizations recognized by OSHA as having the technical capability to perform safety testing and certification of particular types of products. NRTLs provide testing and certification services to the manufacturers of a wide range of products used in the workplace.

OSHA’s Nationally Recognized Testing Laboratory (NRTL) Program - Products Requiring Approval.

1. Electrical conductors or equipment (See Listing of Specific References under 1910.303 and 1910.307).
2. Automatic sprinkler systems.
3. Fixed extinguishing systems (dry chemical, water spray, foam, or gaseous agents).
4. Fixed extinguishing systems components and agents.
5. Fire detection device for automatic actuation of total flooding system.
6. Portable fire extinguishers.
7. Automatic fire detection devices and equipment.
8. Employee alarm systems.
9. Self-closing fire doors (openings to inside storage rooms for flammable or combustible liquids).
10. Fire doors [1 ½ hour (B) rated] (openings, to other parts of a building, of storage rooms for liquefied petroleum gas (LPG)).
11. Metal frame of windows in partitions of inside acetylene generator rooms used in oxygen-fuel welding and cutting.
12. Heat actuated (closing) devices (dip tanks containing flammable or combustible liquids).
13. Self-closing fire doors (including frames and hardware) used in openings into an exit.
14. Flame arresters, check valves, hose (transfer stations), portable tanks and safety cans - (flammable/combustible liquids).
15. Pumps and self-closing faucets (for dispensing Class I liquids).
16. Flexible connectors (piping, valves, fittings) - (flammable liquids).
17. Service station dispensing units (automotive, marine).
18. Mechanical or gravity ventilation systems (automotive service station dispensing area).
19. Automotive service station latch-open devices for dispensing units.
20. New commercial and industrial LPG consuming appliances.
21. Flexible connectors (piping,valves, fittings) - LPG.
22. Powered industrial truck LPG conversion equipment.
23. LPG storage and handling systems ( DOT containers, cylinders).
24. Automatic shut-off devices (portable LPG heaters including salamanders).
25. LPG container assemblies (non-DOT) for interchangeable installation above or under ground.
26. Fixed electrostatic apparatus and devices (coating operations).
27. Electrostatic hand spray apparatus and devices.
28. Electrostatic fluidized beds and associated equipment.
29. Each appurtenance (e.g., pumps, compressors, safety relief devices, liquid-level gaging devices, valves and pressure gages) in storage and handling of anhydrous ammonia.
30. Gasoline, LPG, diesel, or electrically powered industrial trucks used in hazardous atmospheres.
31. Acetylene apparatus (torches, regulators or pressure-reducing valves, generators [stationary and portable], manifolds).
32. Acetylene generator compressors or booster systems.
33. Acetylene piping protective devices.
34. Manifolds (fuel gas or oxygen) - separately for each component part or as assembled units.
35. Scaffolding and power or manually operated units of single-point adjustable suspension scaffolds.
36. Hoisting machine and supports (Stone setters’ adjustable multiple-point suspension scaffold).
37. Hoisting machines (Two-point suspension scaffolds; Masons’ adjustable multiple-point suspension scaffold.

It’s important to note that all items on it need NTRL certification. Anything not on the list can be independently certified from the manufacturer, or other entity, other than an approved NRTL.