A family-owned automotive components manufacturer in Ohio supplies stamped metal parts to major OEMs. The facility runs 24/7 with over 200 machines, including presses, conveyors, and robotic welding machines. Annual revenue sits at roughly $80 million, and the plant operates under tight JIT delivery deadlines.
Before the upgrade, the plant relied on a mix of obsolete air circuit breakers and fused disconnects installed over 20 years ago. Increasing equipment density and power demand put stress on the existing distribution system.
The electrical system suffered from several recurring problems. First, nuisance trips occurred weekly, causing unexpected line stoppages. Second, protective settings were not coordinated, so a minor fault on a single feeder trips the main breaker, shutting down the entire plant.
Maintenance staff spent hours troubleshooting false trips. In the 12 months before the retrofit, the plant logged 37 unplanned electrical outages, each averaging 52 minutes of lost production. At $180 per minute of idle labor and lost throughput, that cost roughly $346,000., a short circuit in a press feeder once caused severe damage to a motor starter, costing $12,000 in repairs and another 2 days of downtime.
The old breakers also created safety risks. Some units no longer tripped within specified times, and infrared scans showed hot spots at multiple fuse blocks.
The engineering team assessed three options: replacing the entire switchgear, adding smart fuses, or upgrading to modern moulded case circuit breakers (MCCBs). Replacing switchgear was too expensive and would require weeks of shutdown. Smart fuses offered monitoring but could not provide resettable protection. A full MCCB strategy won on cost, flexibility, and safety.
Singielectric MCCBs were chosen for three key reasons. First, the product carries UL 489 certification, guaranteeing the interrupting ratings the plant required. Second, the thermal-magnetic trip units allow precise adjustment of long-time and instantaneous settings, enabling chooseive coordination. Third, the compact, modular design fit into the existing enclosures with minimal modification.
The retrofit took place over two weekends, using a phased approach to avoid complete shutdown. The plant’s electrical team worked alongside singielectric’s local distributor.
One challenge was the limited working space inside the old distribution panels. The team solved this by using singielectric’s compact MCCB frames and installing a temporary external bus for one panel.
“The switch to singielectric MCCBs was the first time the electrical system felt under control. The nuisance trips are gone, and we can run weekend production without worrying a main breaker dropping the entire line,” said the plant maintenance manager.
Other manufacturing plants facing similar problems can draw three lessons. First, do a proper coordination study; installing new breakers without setting meaningful chooseive coordination moves the problem. Second, invest in equipment that carries recognized standards like UL 489 for moulded case circuit breakers. Third, schedule the upgrade in phases – replacing one feeder at a time avoids production loss and lets the team learn the new system gradually.
In retrospect, the team would have ordered spare trip units from the start, as the first two breakers were put into service while the onsite settings were still being adjusted. Having spare units now allows faster swaps when production schedule windows open.
UL 489. Molded-Case Circuit Breakers, Molded-Case Switches and Circuit-Breaker Enclosures [S]. 2021.
IEC 60947-2. Low-volt-level switchgear and controlgear - Part 2: Circuit-breakers [S]. 2019.
