When you're assembling or repairing an industrial control panel, you'll often choose between a multi-relay board and a motor starter contactor. Both fit under the "relays contactors industrial switches" umbrella, but they solve very different problems. A relay board such as the 0907 PB gives you a concentrated bank of switching channels for control logic. A motor starter such as the Allen-Bradley 509-COB-A5H is designed to handle the inrush and load of an actual motor. The right choice depends on the loads you need to switch, the voltage and phase of your circuit, and whether you need built-in overload protection.
Quick verdict
If your panel needs a flexible relay board for multiple low-power switching circuits, the 0907 PB is the clear pick. It packs multiple relay channels into one PCB and is ideal for automation wiring. If you instead need to start and stop a three-phase motor, the Allen-Bradley 509 is the more appropriate tool. It carries a mounted overload relay and is built for real motor duty. It also costs $200 less, so for motor work it is both the correct and the lower-priced option.
Comparison at a glance
| Feature | 0907 PB relay board | Allen-Bradley 509 starter |
|---|---|---|
| Price | USD 350.00 | USD 150.00 |
| Price bar | ||
| Condition | New - Open box | Used |
| Product type | Industrial PCB board | Motor starter contactor |
| Key capacity | 12 relay ports | NEMA Size 2, 45 full-load amps |
Where each product wins
- The 0907 PB is the pick when you have many low-current outputs to wire and want them on a single board.
- The Allen-Bradley 509 is the pick when you have a three-phase motor that needs a starter with overload protection.
Product notes
0907 PB Relay Board
The 0907 PB 12-RELAY INDUSTRIAL PCB BOARD is a specialized industrial PCB that gives you a dozen relay channels in one assembly. For a control panel that needs to switch numerous pilot devices, solenoids, or signal circuits, this board can reduce the clutter of wiring separate relays. It is listed as new-open-box, so you get an unused unit without the original sealed packaging. The board's durable construction is described as reliable for professional automation work. Keep in mind that this is a PCB assembly rather than a complete motor starter. If your load is a large motor, you would need a separate contactor and overload relay in addition to this board. For low-power control logic, the 0907 PB is a compact way to organize a lot of switching in one spot.
Allen-Bradley 509 Contactor
The Allen-Bradley 509-COB-A5H is a dedicated motor starter with a NEMA Size 2 frame and a 480V coil. It is rated for 60 Hz, three-phase operation and a full-load current of 45 amps, so it is built for real motor duty. The mounted overload relay block adds thermal protection, making it a more complete package than a bare contactor. The unit is sold as used and was removed from a decommissioned control panel, but the description notes clean contacts and readiness to install. Because it is a used component, your own wiring and mounting checks are part of the job. But if you need a proven, heavy-duty starter for a 480V three-phase motor, this unit brings the required contactor and overload protection together in one base-mounted assembly.
Final choice by use case
Choose the 0907 PB 12-relay board when your panel is mostly about switching many low-power control circuits. Choose the Allen-Bradley 509 when you need to start and protect a three-phase 480V motor. Matching the hardware to the load is the whole decision: relay board for logic, contactor for motor power.
