20/30/50 Amp Generator Power Inlet Box Series
The “20, 30, 50 Amp Generator Power Inlet Box” refers to a series of weatherproof, outdoor-rated electrical inlet boxes designed for safely connecting portable generators to a home’s transfer switch or panel during power outages. These boxes eliminate the need for running extension cords through windows or doors, keeping dangerous exhaust fumes (like carbon monoxide) outside. They are NEMA 3R rated for rainproof outdoor use, constructed from heavy-duty steel or durable nylon with anti-corrosion coatings to withstand rain, UV rays, snow, and impacts. All models are ETL Listed for safety and compatibility with standard generator cords.This series is available in multiple configurations to match common generator outlets, including 3-prong and 4-prong setups. They feature a flip-up spring-loaded cover for protection when not in use, pre-drilled mounting holes for easy installation, and generous internal wiring space (often 50% more than standard boxes) to accommodate thick gauge wires (e.g., 6-10 AWG). Many include a green LED power indicator that lights up when connected and powered on, providing clear visual confirmation.
Available Variants and Specifications
The following table summarizes the key models based on amp rating, NEMA connector type, voltage, wattage, and typical applications. Weight is around 1-2 lbs across models.Made with inlet generator plug Twist-locking, Designed for twist locking generator cord, A good partner for the generator to accommodate the power cord, providing and maintaining continuous backup power supply from the generator outside
| Amp Rating | NEMA Type | Voltage | Max Wattage | Prongs | Typical Use |
|---|---|---|---|---|---|
| 20 Amp | L5-20P | 125V | 2,500W | 3 | Small generators, basic appliances (lights, fridge) |
| 20 Amp | L14-20P | 125/250V | 5,000W | 4 | Mid-size generators, RVs, tools |
| 30 Amp | L5-30P | 125V | 3,750W | 3 | Portable generators for partial home backup |
| 30 Amp | L6-30P | 250V | 7,500W | 3 | Welding machines, high-voltage tools |
| 30 Amp | L14-30P | 125/250V | 7,500W | 4 | RV campers, dryers, full kitchen circuits |
| 30 Amp | TT-30P | 120V | 3,600W | 3 | RV/trailer shore power (less common in series) |
| 50 Amp | L14-50P | 125/250V | 12,500W | 4 | Large generators for whole-home backup |
| 50 Amp | SS2-50P | 125/250V | 12,500W | 3 | Heavy-duty generators, construction sites, farms |
Applications & Ideal For:
- Home Backup Power: The safe and professional way to connect a portable generator to your home’s transfer switch.
- Workshops & Garages: Provides a dedicated, high-amperage inlet for running heavy-duty tools.
- Construction Sites: A durable and secure power inlet for temporary site power.
- RV Parks and Farms: A reliable power connection point for RVs and agricultural equipment.
Critical Safety Notice & Installation:
This inlet box must be installed by a qualified electrician and must be connected to your main electrical panel through a UL-certified Transfer Switch or Interlock Kit. This is mandatory to isolate your generator from the public utility grid, preventing electrocution hazards for line workers and ensuring compliance with national electrical codes. Never plug a generator directly into a wall outlet.
- Mount the box on an exterior wall near your generator’s operating spot.
- Run approved conduit/wire from the box through the wall to your transfer switch.
- Connect the inlet to hot, neutral, and ground wires (4-wire for 125/250V models).
- Secure the generator cord into the inlet when in use; flip cover closed when idle.
- Test with a multimeter before full use. Always turn off the main breaker before connecting.
Generator Power Inlet Box Manufacturer
Our Advantages as a Leading Electrical Plug Manufacturer
With 15+ years as a dedicated power plug and socket factory, we excel in producing types of Generator Plug, Power Cords, Extension Cables with UL (ETL) certified.
- Guaranteed Market Access: Our UL certification eliminates compliance risks, speeding up your product approval process in the United States and Canada.
- Precision Manufacturing: Produced in our ISO 9001-certified facilities with stringent quality control, including continuity, hi-pot, and insulation resistance tests.
- Customization & Support: We offer OEM/ODM services for custom lengths, colors, and packaging. Benefit from rapid prototyping, low MOQs, and dedicated engineering support.
- Cost-Effective Sourcing: As a direct manufacturer, we provide competitive pricing without compromising on quality or safety.
2-year industrial warranty included; free samples for qualified OEMs. Contact our team for quotes or custom plugs, plug adapters, custom electrical plug builds!
