4 pin Molex power connector at the powersupply cable.
The 4-pin peripheral power connector — commonly called the “Molex connector” — is a 5.08 mm pitch crimp connector specified in every major revision of Intel’s ATX Power Supply Design Guide, from the original ATX specification through ATX 3.0 (2023). It delivers +12 V and +5 V rails with two ground returns on 18 AWG wire, and has been the standard internal power connector for 5.25-inch drives, hard disks, and other peripherals since the mid-1990s. The approved housings are the TE Connectivity (formerly AMP) Commercial MATE-N-LOK 1-480424-0 and its Molex equivalents (15-24-4048 / 8981-04P), which are fully interchangeable at 5.08 mm pitch. The housing is rated at 13 A per circuit and operates from −55 °C to +105 °C.
| Pin | Name | Color | Description |
|---|---|---|---|
| 1 | +12V | yellow | +12 VDC |
| 2 | GND | black | +12 V Ground (Same as +5 V Ground) |
| 3 | GND | black | +5 V Ground |
| 4 | +5V | red | +5 VDC |
Signals
- +12V — +12 VDC supply rail; yellow wire, 18 AWG; used to power drive motors and other higher-voltage loads.
- GND — Common ground return shared by both the +12 V and +5 V rails; black wire, 18 AWG. Pins 2 and 3 are both ground to reduce resistance and share current.
- +5V — +5 VDC supply rail; red wire, 18 AWG; used for drive logic circuits.
Notes
- The connector uses a 5.08 mm (0.200 inch) pitch; the housing is polarised by the asymmetric Mate-n-Lok key to prevent incorrect insertion.
- ATX wire-colour convention: +12 V = yellow, +5 V = red, ground = black — mandatory across all ATX peripheral and floppy connector types.
- The socket-side (cable end) housing is AMP 1-480424-0 (TE Connectivity Commercial MATE-N-LOK); the approved contact is AMP 61314-1 (note: some older references list AMP 60619-1, which is a related Mate-n-Lok contact variant from the same family). The mating pin-side housing is AMP 1-480426-0 with contact AMP 60620-1.
- The Molex 8981-04P (also listed as Molex 15-24-4048 in the ATX 3.0 guide) is the interchangeable Molex Disk Drive Power equivalent; the two brands have been codified as alternatives since ATX12V v1.3.
- Maximum current: 13 A per circuit (TE Connectivity rating for 1-480424-0 at 250 VAC); insulation resistance 500 MΩ minimum.
- Wire gauge: 18 AWG for all four conductors, as mandated by the ATX Power Supply Design Guide.
- The connector was inherited from pre-ATX (AT-era) power supplies and the Molex Disk Drive Power Connection System introduced in 1983, making it one of the longest-lived internal PC power connectors.
Connector part numbers
- Socket housing: AMP 1-480424-0
- Socket: AMP 60619-1
- Pin housing: AMP 1-480426-0
- Pin: AMP 60620-1
- Maximum current per circuit: 13 amps
References
- ATX Version 3.0 Multi Rail Desktop Platform Power Supply Design Guide v2.01 — Peripheral Connectors
- ATX 12V Power Supply Design Guide v1.3 (Internet Archive)
- TE Connectivity / AMP 1-480424-0 — Commercial MATE-N-LOK housing, 4-position, 5.08 mm (the 5.25-inch drive “Molex” power connector).