---
title: "What Is Three-phase power? Electrical Glossary | Daniel Electric"
description: "Three-phase power uses three alternating currents offset in time, giving smoother power for large motors and commercial equipment."
url: https://danielelectric.multisites.ai/glossary/three-phase-power
publisher: Daniel Electric
phone: +1-817-481-8606
quote: https://danielelectric.multisites.ai/contact
---

Commercial

# Three-phase power

Three-phase power uses three alternating currents offset in time, giving smoother power for large motors and commercial equipment.

OSHA's electric power glossary says overhead AC transmission lines carry 3-phase current. It lists service of 120/240 volts single phase for residential customers, and 480Y/277 or 208Y/120 for commercial or light industry customers.

Many commercial buildings have three-phase service because air conditioning units, pumps and machinery need it. Homes mostly have single phase. A [transformer](https://danielelectric.multisites.ai/glossary/transformer) and [switchgear](https://danielelectric.multisites.ai/glossary/switchgear) distribute it inside the site. See [commercial electrician](https://danielelectric.multisites.ai/commercial-electrician).

[Daniel Electric can helpCommercial electrician](https://danielelectric.multisites.ai/commercial-electrician)

## Related terms

-   [Transformer](https://danielelectric.multisites.ai/glossary/transformer)
-   [Switchgear](https://danielelectric.multisites.ai/glossary/switchgear)
-   [Voltage](https://danielelectric.multisites.ai/glossary/voltage)
-   [Service entrance](https://danielelectric.multisites.ai/glossary/service-entrance)

## Sources

1.  [OSHA: Electric Power Generation, Transmission, and Distribution eTool glossary](https://www.osha.gov/etools/electric-power/glossary-terms)
2.  [OSHA: Electric Power Generation, Transmission, and Distribution eTool glossary](https://www.osha.gov/etools/electric-power/glossary-terms)

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## Need an electrician in Southlake?

Call and tell us what is going on. A photo of the panel label or the problem helps us come prepared. Quotes on new installations are free.

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