Repair or replace? It’s a question repeatedly faced by plant engineers and maintenance managers. For power distribution equipment, there are four important considerations when making that decision.
“Should I repair or replace my power distribution equipment?”
It’s a common customer question, whether they want to improve reliability, add new features, or just expand the capacity of their existing switchgear lineups. Regardless of the reason for the upgrade, answering that question can be challenging. Distribution equipment manufacturers (DEMs) can help their customers find the right answer by considering four important factors:
- Can the existing structure and bussing be reused?
- What are the unforeseen costs of direct replacement?
- How will it affect the UL marking and end-customer requirement?
- What value can I add to make the customer application better?
If the decision is made to buy new equipment, many DEMs rely on “OEM” or “abbreviated” switchgear lineups. These are UL certified power distribution equipment products that the DEM can tailor to the needs of their customers. That customization process provides the DEM with a value added opportunity as they incorporate control, communication systems, and other customer specified features.
Let’s explore those four questions, as well as the benefits of selecting abbreviated equipment.
1. Can the existing structure and bussing be reused?
Two cardinal rules guide the decisions made by facility engineers and maintenance managers. First is to always strive to minimize downtime, avoiding the need to shut down production or process equipment. Second is to work as efficiently as possible, avoiding unnecessary work and expense when doing maintenance or upgrades.
When looking at upgrades to power distribution equipment, that pushes the decision toward reusing existing structure (cabinets, buckets, and other sheet metal components) and bussing. In almost every case, switchgear can be upgraded by substituting new breakers and other selected internal components rather than a total lineup replacement.
The programming of the new breakers will probably require the same amount of time as if a new lineup were installed. Reconfiguration of the breaker cradles will likely be required, although many suppliers offer adapters and hardware that speed and simplify this activity.
Bussing may be more problematic. If a power capacity increase is part of the upgrade, existing bussing may need to be modified or replaced. If the capacity of the lineup isn’t going to increase, chances are the existing bussing will need little, if any, modification.
In the end, reusing the existing structure and bussing provides the same result as a rip-and-replace, but in less time and less disruption to normal operations. The reliability and functionality improvements are all in the components housed in the enclosures; there’s little or no downside to having them housed in the older structures.
2. What are the unforeseen costs of replacement?
Opting for complete replacement of the older assets is typically a “cleaner” approach, as you don’t need to contend with issues related to modifying or retrofitting the existing structure. If the footprint of the new asset is no larger than its replacement, you are likely to face fewer unforeseen installation snags as space restrictions.
There is, however, the issue of demolition and removal of the old equipment, which cannot be ignored. This step in the upgrade process adds time to the project schedule and increases disruption to your customer’s facility processes.
Also, it is unlikely that existing conduit will be in the correct place, be the correct size, and/or have the correct conductors in place. That means replacing the conduit, as well as all the wiring connecting the unit to your plant processes. Again, that’s additional downtime and disruption.
Finally, there’s the cost and time for design and engineering. Compared to replacing components in the existing structure, total system replacement may be a more time-consuming project. Also, capital investment of new machinery with more sophistication and automation might require greater power reliability, which in turn will add costs.
3. How will an upgrade affect the UL marking?
In the past, upgrading an existing power distribution and control system often caused issues with the UL marking vs. the end customer’s actual requirements. Many panel builders just utilized their UL 508A control file without actually having a UL 1558 file. So, trying to pass off a total switchgear lineup as UL 1558 was suspect without further UL inspections. Today, that is not the case, assuming you select the correct UL components. You also must involve a UL inspector to perform a field inspection, after completion, to approve the total integration of the controls with the UL 1558 power distribution feeder and bus system.
This starts with selecting the proper direct-replacement breakers and other devices for the front end or power side of the unit that are already UL certified for this application. Some DEMs rely on their own UL 1558 file to specify, while others can access a UL extension. On the control side, again, they can utilize their own UL 508 file or, when necessary, include a UL field inspection to complete the project.
One way that DEMs can simplify UL certification and expedite the overall construction process is to purchase abbreviated or OEM version of equipment, which is discussed in detail later in this article.
4. What value can I add to make the customer application better?
Many power distribution equipment manufacturers offer abbreviated units, or preassemblies, that include the primary components and structure. The DEM then completes the equipment, customizing it to the customer’s specifications with the desired control and communication systems, and any other specified add-ons. While the abbreviated units are somewhat standardized, they offer broad customization potential, including bussing that is more robust, with the option of applying special coating
Compared to simply buying and reselling a complete lineup, abbreviated equipment provides DEMs with the opportunity to include value added features. It also enables DEMs to differentiate themselves, since control schemes are often what sets DEMs apart.
Opting for abbreviated equipment naturally enables DEMs to provide faster turnaround because the major components and structures are already in place.
Making the choice: Repair or replace
The bottomline goals for most power distribution equipment upgrades or replacements is to improve reliability and reduce maintenance costs, while increasing capabilities and possibly capacity. All those goals can technically be met by either repair or replace. When choosing between the two options, consider the factors described above to identify the optimum solution for each application.
Sales Enablement Program Manager
ABB Electrification Business