This engineering brief compares the Carlo Gavazzi Inc. GDPH253L120V three-phase definite-purpose contactor to the CC12SA120 IEC contactor as shown in Figure 1.
The featured products demonstrate that the current rating is the least interesting part of the selection process. Instead, this is a system architecture exercise where product selection depends on specifications as well as how the component fits within the greater design.
Key Takeaways
- A UL Listed IEC contactor is the low-friction solution for the UL 508A control panel.
- The IEC contactor is part of an ecosystem while the definite-purpose contactor is a coil and three heavy-duty contacts.
- Similar cost: When purchased in 100-unit quantities, the cost of the featured parts is within $0.83 per unit (U.S. pricing as of 17 Aug 26).
This article is part of the DigiKey Field Guide for Industrial Automation
Location: Select It → Motor Starters
Difficulty: 
Engineer — difficulty levels explained
Author: Aaron Dahlen | MSEE | Senior Applications Engineer, DigiKey
Last update: 17 Aug 2026
Figure 1: Image of the GDPH253L120V (left) and CC12SA120 (right).
Current Capacity Trade-Offs
Both contactors are designed for across-the-line control of induction motors. This immediately shifts the conversation away from the elementary current capacity. Instead, we have a matrix that involves voltage, current, and horsepower. For our purposes, consider two operating points:
| Voltage | GDPH253L120V | CC12SA120 |
|---|---|---|
| 240 VAC | 10 hp | 5 hp |
| 480 VAC | 15 hp | 7.5 hp |
Evaluate contactors at the system level. We see that higher voltages allow a given contactor to control a higher horsepower induction motor.
Certification
The definite-purpose contactor GDPH253L120V is UL Recognized while the CC12SA120 is UL Listed. This is why we don’t often find definite-purpose contactors in an industrial control panel.
This article describes a UL Listed part as one that has already passed a battery of tests. This matters because the IEC contactor provides a certification driven pathway for control panel parts selection. By contrast, the UL Recognized contactor requires more attention. The components are not necessarily rejected from the UL 508A panel, but they may require additional documentation or even a system-level evaluation. The definite-purpose contactors may also require physical isolation as their wire terminals are not finger-touch safe.
Tech tip: Note that the UL Recognized product is a “component” used in a larger system. This can be confusing as the IEC contactor is also a “component.” The term is overloaded. We are not always careful with our language as we conflate the certification language with the shop floor language. In the first case, the contactor is used in a larger system that is certified as a unit. In the second, the IEC contactor is used in a 508A ecosystem that is primarily certified by virtue of the constituent components. In plain language, 508A has preferred components. Other components may be used but they create friction in the certification process. It’s horses for courses as each contactor has its own niche.
UL Listed components may be located at https://iq.ulprospector.com/. In this example, the Carlo Gavazzi model CC12 contactor has a file number of E236208. You and I are unlikely to see this proprietary document. However, it is enough for us to know that the component meets the applicable UL requirements.
Figure 2: UL Listed vs UL Recognized.
Location of Overload Trade-Offs
The IEC contactor can be assembled to control and protect a generic motor. The thermal overload block is a perfect example as the overload function is moved adjacent to the contactor.
By contrast, the definite-purpose contactor has no such provisions. Thermal overload or single-phasing detection must be added elsewhere. For example, three-phase Danfoss MT/MTZ compressors feature an integral motor protector. (Danfoss is not affiliated with DigiKey.)
There are other types of overload detection systems. For example, the 240 VAC (single phase U.S.) hermetically sealed heat pump compressor at my home has a start capacitor. When it fails, the stalled motor will suffer high starting current. In this example, an upstream overcurrent detection system is included. The contactor’s coil is deenergized after a few seconds to limit motor damage.
Tech Tip: An integral thermal trip may require several hours to reset (highly system dependent). This is especially true if the sensor is attached to the motor windings or mounted within a hermetically sealed enclosure. By contrast, an IEC contactor’s thermal overload relay can be reset in a few minutes. This is an important when troubleshooting an overload event. The integral temperature sensor will not reset until the motor cools. However, repeated resets of an external IEC contactor’s thermal overload block can add heat to an already overheated motor. Don’t damage the motor’s insulation.
The IEC Contactor is a Platform
The IEC contactor is the center of a platform of related components as shown in Figure 3. This includes the thermal overload relay, auxiliary contacts, mechanical interlocks and busbars for motor reversing, and even an upstream circuit breaker.
Tech Tip: Let’s call this the classic IEC motor stack consisting of a circuit breaker, contactor, and thermal overload block. To this we add busbars for convenient mounting. We also add auxiliary contacts to meet the application’s control and monitoring needs.
With regards to the IEC contactor, the components are easy to identify as shown in Figure 3. Similar functionality may be engineered into equipment with the definite-purpose contactor. However, the engineering has deeper integration, and the parts are not as easy to identify. For example, the thermal overload block may be integrated incorporated into a compressor.
Figure 3: IEC contactor platform with direct-mounted accessories as described in the CC12SA120 datasheet.
Next Steps
If you haven’t already done so, I would encourage you to complete the UL 508A training. This training provides perspective for the cryptic specifications associated with UL 508A control panel components.
For a technical deep dive, consider my multipart series on the magnetic motor starter.
Parting Thoughts
Interfamily comparisons such as this are my favorite articles to write. They force us to carefully set the boundary conditions that help select a component for a particular application. In this case, the pathway from UL Listing to UL 508A was one of the most import considerations.
About This Author
Aaron Dahlen, LCDR USCG (Ret.), is a Senior Applications Engineer at DigiKey in Thief River Falls. His background in electronics and industrial automation was shaped by a 27-year military career as both technician and engineer, followed by over a decade of teaching.
Dahlen holds an MSEE from Minnesota State University, Mankato. He has taught in an ABET-accredited electrical engineering program, served as coordinator of an electronic engineering technology program, and instructed military technicians in component-level repair.
Today, he has returned to his home in northern Minnesota, completing a decades-long journey that began with a search for capacitors. Read his story here.