Three-Phase Power
Electrical service that delivers power in three alternating phases, the standard for industrial equipment, and a key tenant-fit spec alongside amperage and voltage.
Definition
Three-phase power is the electrical configuration used for most commercial and industrial equipment. Unlike single-phase residential service, three-phase service supports larger motors, compressors, welders, CNC equipment, and EV or forklift charging more efficiently. In small bay and flex leasing, brokers and tenants usually talk about available amps and voltage together with phasing: for example, 200–400 amp, 120/208V or 277/480V, three-phase. Light industrial and flex suites commonly fall in the 200–400 amp band; heavier manufacturing needs more. Upgrading service after lease signing is expensive and often schedule-breaking, so power should be verified at the unit panel and building switchboard during due diligence. Amperage is not the same as watts per square foot, but both show up in tenant underwriting when equipment lists are known.
Example
A metal fabricator needs 400 amp, 208V three-phase service for welders and a plasma table. Two otherwise identical 2,500 SF grade-level suites are available: one has 200 amp single-phase, the other 400 amp three-phase. The fabricator takes the three-phase unit even at a slightly higher rent because a service upgrade would cost more than the rent delta over the lease term.
See Also
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