What is the current rating of 38999 connector?
Jul 10, 2025
The current rating of a MIL-DTL-38999 connector depends on several factors, including:
Contact size
Number of contacts
Material (plating, shell)
Series (I, II, III, IV)
Wire gauge
Temperature rise and derating requirements
Below is a general guide to the current ratings based on contact size commonly used in 38999 connectors:
Typical Current Ratings by Contact Size (per contact)
| Contact Size | Wire Gauge (AWG) | Typical Max Current |
|---|---|---|
| Size 22D | 24–22 AWG | 5 Amps |
| Size 20 | 20–22 AWG | 7.5 Amps |
| Size 16 | 16–18 AWG | 13 Amps |
| Size 12 | 12–14 AWG | 23 Amps |
| Size 10 | 10–12 AWG | 33 Amps |
| Size 8 | 8–10 AWG | 46 Amps (power contacts only) |
| Size 4 / 0 | 4–0 AWG | Up to 100+ Amps (custom cases) |
Notes:
These are per-contact ratings under standard ambient conditions (~25°C).
The actual current limit can be lower in high-density layouts, or derated for high ambient temperatures.
Power inserts (e.g., with size 8 or larger contacts) are available for higher current-carrying applications.
In some configurations, 38999 connectors may carry up to 100A+, but this typically requires:
Special insert arrangements
Lower contact density
Oversized contacts
Appropriate thermal management
Example: MIL-DTL-38999 Series III, 12-10 Insert with Size 12 Contacts
Number of contacts: 3
Contact size: 12
Max current per contact: 23A
Total connector rating: 69A (if all contacts used for power, which is rare)
Important Considerations:
Always check the manufacturer's datasheet for exact current ratings based on your specific insert and shell.
Derating is essential: Military and aerospace applications often apply a 50% safety factor.
Mixed contact configurations (signal + power + coax + fiber) affect the total current capability.
Summary
| Maximum Current (general) | Up to ~46 A per contact |
|---|---|
| Depends on | Contact size, wire gauge, layout, thermal conditions |
| For high-current | Use size 8, 4, or custom power inserts |
