Reliance Controls PB31
Reliance Controls PB31 Power Inlet Box User Manual
Model: PB31
Introduction
This manual provides detailed instructions for the safe installation, operation, and maintenance of the Reliance Controls PB31 3,750-Watt 120V Pro/Tran Generator NEMA 3R Outdoor Power Inlet Box. Please read this manual thoroughly before installation and use to ensure proper function and safety.
Important Safety Information
DANGER: RISK OF ELECTRIC SHOCK.
- DO NOT START THE GENERATOR UNTIL THE CORD IS CONNECTED TO THIS INLET AND THE GENERATOR.
- ANY TERMINAL MAY BE ENERGIZED WHEN THE CORD IS CONNECTED.
- SHUT DOWN THE GENERATOR PRIOR TO DISCONNECTING THE CORD FROM THIS INLET AND THE GENERATOR.
- FOR POWER INLET ONLY. NOT FOR USE AS AN OUTLET.
- NOT FOR INDOOR USE.
- Always follow local electrical codes and regulations.
- Installation should be performed by a qualified electrician.

Product Features
- NEMA 3R Rated Enclosure: Designed for outdoor use, providing protection against rain, sleet, and external ice formation.
- 3,750-Watt, 120V Capacity: Suitable for connecting a 120V generator to a transfer switch or panel.
- L5-30P Inlet: Standard 30 Amp, 120 Volt locking inlet for secure connection.
- Spring-Loaded Auto-Closing Cover: Weatherproof cover prevents ingress of debris, insects, and moisture when not in use.
- Pre-Wired Built-In Grounding: Simplifies installation with easy access to wiring terminals.


Setup and Installation
Note: Installation must comply with all applicable electrical codes and standards. It is highly recommended that a qualified electrician perform the installation.
- Choose Location: Select a suitable outdoor location for the power inlet box. It should be easily accessible and close to where the generator will be operated. Ensure the location allows for proper conduit routing to the transfer switch or main panel.
- Mounting: Securely mount the PB31 to a wall or suitable surface using appropriate fasteners. The enclosure is designed for surface mounting.
- Conduit Connection: Knockouts are provided on the enclosure for conduit connections. Remove the necessary knockouts and install appropriate conduit fittings.
- Wiring:
- Route the appropriate gauge wire (e.g., 10 AWG for 30A, 120V) from the transfer switch or main panel through the conduit to the PB31 inlet box.
- Connect the wires to the corresponding terminals inside the inlet box. The PB31 typically uses a 2-pole, 3-wire grounding configuration (L5-30P). Connect the hot wire(s) to the brass terminals, the neutral wire to the silver terminal, and the ground wire to the green grounding screw.
- Ensure all connections are tight and secure.
- Seal Enclosure: After wiring, ensure the cover is properly closed and sealed to maintain the NEMA 3R rating.
- Test: Before connecting a generator, verify all wiring connections and ensure there are no shorts.


Operating Instructions
Follow these steps to safely connect and operate your generator with the PB31 Power Inlet Box:
- Generator Preparation: Ensure your generator is turned OFF and all loads connected to it are disconnected.
- Connect Power Cord: Connect the appropriate generator power cord (L5-30P male plug) to the PB31 power inlet. Twist to lock the connection.
- Connect to Generator: Connect the other end of the power cord to your generator's output receptacle.
- Start Generator: Start your generator according to its manufacturer's instructions.
- Transfer Power: Operate your transfer switch (if applicable) to transfer power from utility to generator.
- Disconnecting:
- Before disconnecting, shut down the generator.
- Operate your transfer switch to transfer power back to utility (if applicable).
- Disconnect the power cord from the generator first, then from the PB31 power inlet.
WARNING: Never attempt to connect or disconnect the power cord while the generator is running or under load.
Maintenance
The Reliance Controls PB31 Power Inlet Box requires minimal maintenance. Regular inspection is recommended to ensure continued safe operation.
- Periodic Inspection: Annually, or before each use season, inspect the inlet box for any signs of physical damage, corrosion, or loose connections.
- Cleanliness: Keep the inlet free of dirt, debris, and insect nests. The spring-loaded cover helps prevent this, but occasional cleaning may be necessary.
- Cover Functionality: Ensure the spring-loaded cover opens and closes smoothly and seals properly.
- Wiring Integrity: If comfortable and qualified, periodically check the internal wiring connections for tightness. Always disconnect all power before opening the enclosure.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No power from generator through inlet. |
|
|
| Inlet cover not closing properly. |
|
|
Specifications
- Model: PB31
- Manufacturer: Reliance Controls
- Power Rating: 3,750 Watts
- Voltage: 120 Volts
- Amperage: 30 Amps
- Inlet Type: NEMA L5-30P
- Enclosure Type: NEMA 3R (Outdoor Rated)
- Product Dimensions: Approximately 4 x 2.63 x 6 inches
- Item Weight: Approximately 1.88 pounds
- Part Number: PB31
Warranty Information
The Reliance Controls PB31 Power Inlet Box includes a full manufacturer warranty. For specific details regarding warranty coverage, duration, and claims procedures, please refer to the documentation provided with your purchase or visit the official Reliance Controls website.
Customer Support
For technical assistance, troubleshooting, or parts inquiries, please contact Reliance Controls customer support. Refer to the contact information provided in your product packaging or on the official Reliance Controls website.
You can also visit the Reliance Controls Store on Amazon for more product information and resources.
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