Control-panel adaptability benefits from spare I/O points and additional space

Figure 1: Michael Blass is design team manager at Concept Systems, a CSIA-certified system integrator headquartered in Albany, Oregon.

Michael Blass is design team manager at Concept Systems, a CSIA-certified system integrator headquartered in Albany, Oregon (Figure 1).

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Is NFPA 79 still the go-to standard? What does it tell us about installing electrical equipment properly?

Michael Blass, design team manager, Concept Systems: NFPA 79 is certainly one of the key standards to consider, but it's important to recognize that not all control panels require industrial machinery-level compliance.

In cases where NFPA 79 is applicable, it plays a vital role in ensuring that human-machine interactions and electrical safety hardware adhere to a standardized methodology. This consistency is crucial, as it allows both operations and maintenance personnel to easily understand and operate the system. However, the need for NFPA 79 compliance should be evaluated based on the specific requirements of each project, as other standards may be more relevant depending on the application.

How does proper routing ensure cable protection outside the enclosure, and why are bundling and labeling important?

Figure 2: Important parts of cable configuration in and out of the cabinet are accurate bundling and clear labeling.

Michael Blass, design team manager, Concept Systems: One of the biggest threats to system reliability is the integrity of the interconnect hardware. Sharp edges, burrs and even minor vibrations in machinery can lead to the premature failure of cable and wire insulation. This is why proper routing and effective strain relief techniques are critical—they help protect the cables from these potential hazards. Equally important is accurate bundling and clear labeling (Figure 2). Proper labeling ensures that if a cable or wire causes issues, it can be quickly identified at both ends, making troubleshooting faster and more efficient. Additionally, it aids in aligning the physical wiring with the design documentation, reducing the risk of errors during maintenance or modifications.

Can you explain the different types of termination devices and the best applications for each?

Michael Blass, design team manager, Concept Systems: There are several categories of termination methods for panel wiring, but they generally fall into two main types: screw clamp and spring cage. While there are various versions within each category, these two styles are the foundation of most termination methods.

Screw termination, which has the longest history, involves securing the wire by torquing it to a specific pressure to prevent it from loosening over time. This method requires the use of calibrated torque drivers, adding both cost and time—not just in the initial procurement, but also in the ongoing maintenance of the tools. While screw clamps have been reliable for decades, they can be less efficient and more labor-intensive.

In contrast, spring cage technology is becoming increasingly popular due to its ease of use and resilience in high-vibration environments. Unlike screw clamps, spring cage terminals do not require specific torque, making them more straightforward to install. A version of this technology, known as push-in terminals, further simplifies the process. With push-in terminals, no special tools are needed—wires of a certain minimum size can be directly inserted into the spring cage, and removal is as simple as pressing a button. The only caveat is that push-in terminals require the use of wire end ferrules. However, this is often not an issue since many customers already mandate the use of ferrules for all terminations.

Overall, the choice between screw clamp and spring cage methods depends on the specific application requirements, including factors like vibration levels, ease of maintenance and the need for specialized tools.

Considering the increasing complexity of machinery and the critical role of control panels, how can you effectively balance the demand for faster time-to-market with the need for robust, long-lasting control panels?

Michael Blass, design team manager, Concept Systems: In today's fast-paced, just-in-time manufacturing environment, we achieve success by leveraging standard designs that incorporate built-in flexibility. One key approach is the inclusion of 20% spare I/O points and additional space in control panels, along with slightly oversized variable-speed motor controllers. This strategy reduces the level of detail required during the design phase and enables the early procurement of long-lead-time components.

The provision of spare I/O points and additional space offers significant advantages, such as the ability to accommodate future expansions, updates and adaptations to evolving regulations. By planning for these contingencies upfront, we ensure that the control panels remain robust and adaptable over time.

Similarly, slightly oversizing variable-frequency drives (VFDs) and servo drives, within reason, provides crucial benefits. It allows for motor sizing to be finalized later in the design cycle, offering flexibility during development. Additionally, these oversized components are better equipped to handle the demands of aging motors that may operate continuously at the higher end of their ampacity range, reducing the risk of premature failure and extending the overall lifespan of the control panel.

By balancing the need for speed with thoughtful design considerations, we can deliver control panels that meet the demands of rapid time-to-market while maintaining the durability and reliability required for long-term performance.

What are the most effective methods for standardizing panel design and components while maintaining flexibility to accommodate diverse machine requirements?

Figure 3: Standardizing hardware and panel layouts across systems can significantly reduce overall design time, allowing for greater focus on creating adaptable solutions.

Michael Blass, design team manager, Concept Systems: Incorporating flexibility into control panel design is essential for minimizing budget and schedule impacts, particularly when dealing with one-off turnkey machinery. However, the diverse requirements of each application can make this a complex task. To address this, standardizing hardware and panel layouts across systems can significantly reduce overall design time, allowing for greater focus on creating adaptable solutions (Figure 3). This approach not only streamlines the design process but also mitigates the impact of changes during both the design cycle and system commissioning. The foundation of this flexibility lies in building spare capacity wherever possible.

For instance, even when a functional safety level of Category 2, Performance Level C, is required, opting for the slight increase in labor and hardware costs to achieve a Category 3, Performance Level D system often proves advantageous. This proactive approach allows for potential hazards that could elevate the required safety level to be addressed later in the design or commissioning process, without disrupting budgets or schedules.

Another effective strategy is substituting VFDs for full-voltage direct-on-line (DOL) starters. This decision has multiple benefits. First, VFDs offer motor speed adjustability, which is crucial since the exact speed required for a system’s cycle time is often estimated early on. In fixed motor and gearbox applications, DOL starters do not allow for speed adjustments, making any necessary changes costly in terms of both hardware and labor.

While VFDs may initially cost up to three times more than DOL starters, they provide a safeguard against late-stage speed adjustments, thereby protecting the project timeline and budget. Additionally, using the same motor and VFD sizes across various applications simplifies parts selection and spares management.

The second impact is on installation labor costs. As Ethernet communications become more prevalent in machinery, the extensive labor hours traditionally required for I/O wiring of DOL starters are significantly reduced. Ethernet connections streamline the process, reducing complexity and saving time.

Finally, modern VFDs often include functional safety-rated safe-torque-off (STO) control. This feature enhances motor safety control without the need for additional contactors and safety wiring, minimizing hardware within the panel and leaving extra space for potential design changes or future system expansion.

By standardizing key components while incorporating these flexible strategies, control panel designs can accommodate diverse machine requirements without sacrificing efficiency, safety or long-term adaptability.

Tell us about your company’s panel-building and -wiring capabilities.

Figure 4: Concept Systems’ panel shop is fully equipped to handle all aspects of control panel production, including the precise interconnect cabling and external wiring necessary for comprehensive, turn-key system solutions.

Michael Blass, design team manager, Concept Systems: Concept Systems is a UL508A-certified panel shop with more than two decades of specialized experience in control panel fabrication. Our extensive portfolio includes a wide range of applications, from basic remote I/O junction boxes designed for mild, Type 1, environments to complex, multi-door control system panels engineered for harsh, caustic conditions, Type 4X.

Our panel shop is fully equipped to handle all aspects of control panel production, including the precise interconnect cabling and external wiring necessary for comprehensive, turn-key system solutions (Figure 4). This ensures that every panel we deliver meets the highest standards of quality, durability, and reliability.