Photo Credit: IRISS
Infrared inspection windows are usually found on high voltage equipment where opening panels for inspection is not always safe and feasible. During a shutdown, panels are cut to accommodate IR inspection windows in locations that give the best view of critical connections and components. During the course of a typical electrical infrared inspection, the majority of the equipment is of a low voltage. Under most circumstances, these panels can be opened for a thorough qualitative inspection. In some cases, however, site-specific safety requirements will not allow for the opening sections of critical power distribution panels for inspection of wire connection. In this instance, the addition of specifically placed IR windows can allow for inspection of these critical connections. Here is a case study from a facility that experienced a plant-wide shutdown due to the failure of a breaker on a power distribution panel on the plant floor.
A plant-wide, yearly IR scan was completed. Faults were documented and a report was sent out. A few months after the scan, a critical failure occurred on a power distribution panel that shut down a critical piece of equipment. In turn, the plant shut down. During the initial IR scan, no fault was documented on this piece of equipment. Due to safety concerns, this facility would not allow for the disassembly of the panel covers over the breaker wire connection. Though some heating could have been observed on the breaker itself, the air gap between the faulty wire connection and the outer surface of the panel cover did not show the desired thermal gradient that would have indicated the actual severity of problem that was lying underneath.
In many instances, site-specific safety protocols can affect the quality of an infrared scan. In this case, if the panel covers were able to be removed, then the fault most likely would have been easily found. As a solution to avoid missing any critical faults in the future, a custom panel front was ordered and installed to allow for the addition of IR windows at all critical breaker wire connections for this power distribution panel. This facility has also gone one (or many) steps further. They plan to add custom IR window panel fronts to all critical distribution panels to help maximize the effectiveness of the infrared scan in the safest manner possible.