The NEMA 5-15P is the most common power-cord plug in North America. If you picture a “normal” wall plug — two flat parallel blades plus a rounded grounding pin — you are picturing a 5-15P. It is rated 15 amperes at 125 volts and mates with the equally ubiquitous 5-15R receptacle found in homes and offices across the United States and Canada.
Configuration and Ratings
In NEMA nomenclature, the leading “5” identifies the 125-volt, three-wire grounding configuration; “15” is the amperage; and the trailing “P” marks it as a plug (a receptacle would be “R”). The three contacts are:
- Hot — the narrower of the two flat blades
- Neutral — the wider flat blade, which enforces polarization
- Ground — the rounded or U-shaped pin, slightly longer so it makes contact first
Because the grounding pin engages before the current-carrying blades, any fault is routed safely to ground before the device energizes. This is the core safety advantage of the grounded 5-15 pattern over the older two-blade designs.
Typical Applications
The 5-15P appears on the vast majority of grounded consumer and commercial equipment: computers and monitors, kitchen appliances, power tools, medical devices and general-purpose extension cords. When paired with an IEC 60320 connector at the appliance end, it forms the detachable computer-style cordset used worldwide with region-specific plugs.
Construction Notes
Plugs are produced either as field-wireable assemblies (screw terminals inside a shell) or, far more commonly, as over-molded cordsets where the plug body is molded directly onto the cord. Over-molding integrates the strain relief into the plug and produces a sealed, tamper-resistant assembly. The blade material is typically brass, sometimes nickel-plated, chosen for conductivity and spring retention.
Standards and Compliance
Blade dimensions and spacing are defined by NEMA and harmonized in the ANSI/NEMA WD-6 standard for wiring devices. Safety listing to UL 498 (attachment plugs and receptacles) is standard for products sold in the United States. Specifying a 5-15P is rarely about the plug alone — it is about matching the plug rating to the cord gauge and the downstream connector so the whole cordset is rated as a system.