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Power Connectors

Barrel jacks, IEC, NEMA, and regional power plugs.

3 connector types documented

Barrel Jack

DC Barrel Connector

EIAJ (some sizes), otherwise de facto

Max Speed

0 Mbps

Max Power

120W

Connector

2 pins, 5.5×5.5mm

Common Uses

Laptops (older models) Routers and modems LED strips +6 more

⚠️ 5.5x2.1mm and 5.5x2.5mm look nearly identical but 2.1mm plugs are loose in 2.5mm jacks

Barrel connectors are one of the most frustrating connector types due to complete lack of standardization. Dozens of sizes exist, polarity varies by manufacturer, and voltage ranges from 3V to 48V. The only way to know compatibility is to check all specifications. Despite this chaos, they remain common because they're cheap, simple, and adequate for low-power DC applications. USB-C Power Delivery is slowly replacing them.

IEC 60320

IEC 60320 Appliance Couplers

IEC (International Electrotechnical Commission)

Max Speed

0 Mbps

Max Power

4000W

Connector

3 pins, 30×22mm

Common Uses

Desktop computers Monitors Servers +7 more

⚠️ C13 fits into C14 inlets, C14 is the plug on the device - confusing naming

IEC 60320 connectors standardized appliance power connections worldwide. The ingenious aspect is separating the appliance connector (universal) from the wall plug (country-specific), so manufacturers can ship one product globally with different power cables. C13/C14 dominates computing, while C19/C20 handles data center and high-power needs.

NEMA

NEMA AC Power Plugs and Receptacles

NEMA (National Electrical Manufacturers Association)

Max Speed

0 Mbps

Max Power

12500W

Connector

3 pins, 32×22mm

Common Uses

All US household electronics Computers and monitors Kitchen appliances +5 more

⚠️ 5-15 and 5-20 receptacles look similar but 5-20 has a T-shaped neutral slot

NEMA connectors are the North American standard, used in the US, Canada, Mexico, and some other countries. The system uses different physical configurations to prevent connecting devices to incompatible voltage/amperage circuits. The 14-50 outlet has become popular for EV charging since it's commonly available for RVs and electric ranges.

About Power Connectors

Power connectors vary by region, voltage, and current requirements. Using the wrong connector or adapter can be dangerous.

DC Power

  • Barrel jacks - Electronics, laptops
  • USB-C PD - Modern universal charging
  • Proprietary - Manufacturer-specific

AC Power

  • IEC C13/C14 - Computer power cables
  • NEMA - North American outlets
  • Type G, F, etc. - Regional standards