Permanently installed equipment powered by internal combustion engines must be installed according to which standard?

Permanently installed equipment powered by internal combustion engines must adhere to NFPA 37. This standard specifically focuses on the installation and operation of internal combustion engines that are intended for fixed installations, which relates directly to ensuring safety, reliability, and performance. NFPA 37 provides guidelines on topics such as location, ventilation, exhaust systems, and fuel supply. This is crucial because effective installation can mitigate potential hazards associated with operating internal combustion engines, such as fire risks and emissions issues.

In contrast, while NEMA 250 addresses enclosures for electrical equipment that could also relate to installations, it does not specifically guide the unique requirements for internal combustion engines. NFPA 70, or the National Electrical Code (NEC), primarily covers electrical installations and wiring, which, while important, does not directly apply to the specifics of internal combustion engine installations. UL 875 pertains to standards for particular types of safety testing, but again, it does not focus specifically on the installation of equipment powered by internal combustion engines. Therefore, NFPA 37 is the appropriate standard that consolidates the necessary guidelines for the installation of these types of systems.