Best 5 50-Amp Power Inlet Boxes (NEMA SS2-50P Tested)
The best 50-amp power inlet boxes feature heavy-gauge steel or powder-coated aluminum with NEMA 3R rainproof ratings. Our top recommendation is the Reliance Controls PB50 for its spacious wiring compartment and bottom-entry knockouts.
01 Why Metal Inlet Boxes Outperform Plastic During Storms
A power inlet box is mounted on the outside of your house to receive emergency generator power. Plastic boxes can crack during winter hail and degrade under summer sun.
Steel and powder-coated aluminum enclosures resist physical impacts and seal tightly against blowing rain. They prevent moisture from shorting out high-voltage conductors.
- Heavy-gauge metal prevents distortion when twisting in heavy cords.
- Bottom-entry conduit knockouts keep water from seeping into walls.
- Spring-loaded flip covers protect terminal prongs when disconnected.
02 Top 5 50-Amp Weatherproof Power Inlet Boxes
The Reliance Controls PB50 is the industry standard for 50-amp residential installs. It offers 33 percent more interior wiring volume than compact competitors.
Connecting your box requires heavy wire. Size your conduit run to your electrical panel with the help of a certified local electrician.
| Inlet Box Model | Material | Conduit Knockouts | Power Light | Rating |
|---|---|---|---|---|
| Reliance Controls PB50 | Powder-Coated Steel | Bottom & Sides | No | 9.8 / 10 |
| Reliance Controls PBN50 | Non-Metallic Resin | Bottom Only | Yes | 9.3 / 10 |
| Conntek 50A Steel Box | Galvanized Steel | Bottom & Back | Yes | 9.1 / 10 |
| Generac 6344 50A Box | Aluminum Enclosure | Back & Bottom | No | 9.0 / 10 |
| Champion 50A Metal Box | Steel with E-Coat | Bottom Only | No | 8.9 / 10 |
03 Installation and Conduit Best Practices
Bending 6 AWG copper conductors inside a tight electrical box is difficult without proper depth. Use conduit with at least 1-inch diameter to make wire pulls smooth.
Apply silicone sealant around the top and side exterior edges of the box, leaving the bottom edge open for weeping condensation.
- 1 Mount Securely to Studs: Anchor the box directly to house framing rather than thin vinyl siding.
- 2 Torque Terminal Screws: Torque electrical lugs to manufacturer specs to prevent hot spots.
- 3 Seal Exterior Edges: Caulk the perimeter with exterior silicone to keep rainwater out.
- Select metal NEMA 3R boxes with generous interior wiring room.
- Use bottom-entry conduit knockouts to prevent water intrusion.
- Torque all terminal lugs to spec to stop terminal overheating.
Frequently Asked Questions
Q: Can I install a 50-amp inlet box on 30-amp wire?
No. The wire connecting your inlet box to the breaker panel must match the 50-amp rating of the box using 6 AWG copper conductors.
Q: Why do some inlet boxes have an LED indicator light?
The LED light shows you that the generator is successfully sending power through the cord before you flip the indoor transfer breaker.
Q: What is the best height to mount a generator inlet box?
Mount the box between three and five feet above the ground to keep it above winter snowdrifts and make plugging in comfortable.