Energy-Saving Single-Phase Oil-Immersed Pole-Mounted Transformer
15KVA 13.8KV/0.4KV
See DetailsMost international electrical standards treat 480 volts AC as part of "low voltage" distribution—because IEC defines low voltage up to 1,000 VAC—while some North American industry and regulatory documents use lower thresholds (commonly 600 V) for certain equipment or workplace rules. Practical safety rules, however, treat 480 V as a dangerous voltage that requires full electrical safety procedures.
The International Electrotechnical Commission (IEC) treats "low voltage" for power distribution as any rated voltage up to and including 1,000 V AC (and up to 1,500 V DC) in documents that standardize protection against electric shock and equipment categories. Under IEC wording, a 480 VAC three-phase system fits squarely within the low-voltage category.
The U.S. National Electrical Code (NEC) and associated U.S. standards do not always use the single term "low voltage" consistently. Practically speaking, design and equipment practice in North America often treats circuits 600 V or less as the common distribution range for commercial/industrial installations, and larger requirements or different product classes apply above that. Other U.S. guidance and trade resources point out that for some code applications the 1,000 V cut-off is used; for others, 600 V is the practical dividing line used by equipment manufacturers and state safety regulations.
OSHA does not define "low voltage" as a single category but enforces guarding/safety rules starting at voltages of 50 V and up for many workplace protections. State-level regulations (for example Cal/OSHA) may group requirements by ranges such as 0–600 V and above 600 V for some electrical safety orders, which is why 480 V often falls under the "low-voltage distribution" rules for workplace procedures yet is still treated as hazardous.
"Low", "medium" and "high" voltage are labels created for convenience and change by technical community and legal context. IEC uses a higher numeric ceiling for "low voltage" (≤1,000 V AC), while many U.S. organizations and utility/installation practice use 600 V as a practical breakpoint for distribution equipment classes. Safety rules are written around risk thresholds (for example OSHA's 50 V safety enforcement) rather than consistent naming, so the same numeric voltage may be described differently depending on whether the writer discusses equipment ratings, product standards, installation rules, or worker safety.
When you specify motors, switchgear, breakers or transformers for a 480 V system, select components with appropriate voltage and interrupting ratings, listed/marked for 480 V use, and compliant with the standards that apply in your jurisdiction (UL, ANSI, IEC, etc.). Even if a standard calls 480 V "low voltage," that label doesn't reduce the need for components rated for the available fault current and thermal/mechanical stresses.
Treat 480 V as a live hazard: apply NFPA 70E arc-flash risk assessments, lockout/tagout procedures, and use PPE and safe work practices appropriate to the calculated incident energy. Many workplaces require qualified-person procedures for any circuits ≥50 V; therefore 480 V always demands qualified personnel and documented safety controls.
Design practice for 480 V systems typically includes a grounded neutral (for 277/480Y systems), coordinated overcurrent protection sized for conductor ampacity and motor starting, and selective device coordination to clear faults without unnecessary service interruptions. Follow the local edition of the NEC and equipment manufacturers' installation instructions.
| Authority / standard | Classification threshold | How 480 V is treated |
| IEC (e.g., IEC 61140) | ≤ 1,000 V AC = Low voltage | Low-voltage distribution (480 V included) |
| NEC / U.S. practice | Varies; many uses ≤ 600 V as distribution | Distribution class (commonly ≤600 V) — 480 V is typical industrial supply |
| OSHA (workplace safety) | Safety rules apply at ≥ 50 V | Always hazardous; requires qualified-person procedures |
Numerically, 480 V is "low voltage" under IEC (≤1,000 V) but sits near the top of the distribution range for North American installations where 600 V is often the practical breakpoint. Regardless of label, 480 V is a serious electrical hazard: design for correct equipment ratings, perform arc-flash and coordination studies, and enforce qualified-person, lockout/tagout and PPE rules on all exposed 480 V work. When in doubt, check the specific code, utility, or employer rule that governs your installation.
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