Case Study

Case Study #122 | A critical step in preventive maintenance for your uninterruptible power supply

Apr 30, 2018 | Case Study

“We don’t want to take a chance on our UPS system not working.”
“What if there’s an outage while you’re doing your PM?”
“Can’t you just do all your checks with the UPS online?”
“We’re not ready to take that chance while you inspect it.”

All of the above comments and questions have been heard by Nationwide Power’s Critical Power Professionals™ at some point while performing preventive maintenance on uninterruptible power supply systems. This poses a problem that further exposes you – the customer, to potentially unforeseen problems.

Certain issues can be overlooked by not allowing your UPS system to be transferred to or from bypass mode. More thorough inspections can be performed that include vital checks for loose mechanical connections, loose wiring to and from circuit boards, visual checks deep inside the UPS (in areas that would be powered down while in bypass mode), and operational verification of motorized breakers or contactors. By avoiding these necessary examinations, your UPS system may be vulnerable to more costly problems and repairs in the future.

Unfortunately, one of our customers just found themselves in this exact situation. They refused to allow their UPS system to be transferred to bypass mode for many years, citing that “the risk was too high that we might lose power during the preventive maintenance”. Very recently, their UPS system had failed. Upon further inspection, it was noted that the magnetics of the system needed a major cleaning – the kind of cleaning that is safely done with the unit offline, isolated, and panels removed. Because this cleaning did not take place, excessive dirt and debris had built up on these critical components. This caused excessively high operating temperatures and eventually a catastrophic failure. The customer had been notified of the need to allow service while in bypass but opted to forego this due to concerns of an outage during the inspection.

In previous case studies, similarities between vehicle and UPS system maintenance have been used. In this case comparison, it would be as if you were to leave the car running while requiring the auto-mechanic to carefully examine the vehicle before a family road-trip. It is highly doubtful that the inspection would be very thorough.

Our Critical Power Professionals™ recommend annual preventive maintenance, with the UPS system placed offline in bypass mode. Scheduling the inspection during the most “non-critical” time for your company, as well as precise coordination between all departments may be required to mitigate a potential utility outage while in bypass. This planning will go a long way to ensuring that a more detailed inspection is performed on your UPS system under controlled circumstances, as opposed to an unwanted emergency call.

Have questions or ready to schedule your next preventive maintenance? Our Critical Power Professionals ™ are here to help.

Nationwide Power provides 24/7/365 technical support to ensure that everything operates and transitions successfully before, during, and after any power outage.

Request a quote Call | 800-868-2780 E-Mail

We are your critical power infrastructure partner!

Latest News

Case Study #156 | Importance of Following Age Based Recommendations

Case Study #156 | Importance of Following Age Based Recommendations

Case StudyIn this Nationwide Power™ (NP™) case study, we highlight the importance of following your service provider’s age-based components. The most common age-based components are batteries (every 3-5 years), fans (every 5 years), capacitors (every 5-7 years), and...

Newsletter Signup

Sign up below to stay informed with latest industry trends, products, and news.


Submit a Comment

Your email address will not be published.



January 11, 2024

"Breck is always courteous and professional, and of course he really knows his stuff!"

View All - Mark B


Sign up below to stay informed with latest industry trends, products, and news.

Pin It on Pinterest