|We often get asked about the plastic viewport approach to allow infrared inspection of electrical cabinets without opening the panel doors. The idea is that this approach makes it safer for thermographer to do inspections because they don’t have to open the doors.
While we support an approach that allows inspections to be done without opening the doors, we believe very strongly that this approach is dangerous to the thermographer and to anyone proximate to these panels. The panel doors are there for a reason, namely to protect people from hurting themselves and making the area safer in the event of an arc flash and/or explosion.
Putting an open hole in the panel door that’s
> ½” wide protected by nothing more than a plastic port and plastic cover defeats this safety mechanism. IEE regulation 412-03-01 that states, “Live parts shall be inside enclosures or behind barriers providing at least the degree of protection IP2X”. The 5/8” hole is in contravention of IP2X and can negate the safety rating of the cabinets.
A customer described how a person electrocuted themselves when they attempted to measure the distance from the door to the bus bar with a tape measure through a vent. As a result of incident like this, utilities are replacing doors with vents with fully protected enclosures.
In addition, the viewport approach requires a big and expensive proprietary lens to look through their 5/8” view hole. This means that anyone installing these view holes is locked into a single camera supplier forever. The lens can’t focus beyond 45” so it’s useless for any other applications.
We believe that IR windows accomplish the same goal in a much safer manner. Many even include a locking metal cover for further protection (IP65). Nothing can penetrate the cabinet and no safety ratings are compromised. In fact, many OEM cabinet makers are offering doors with the IR windows already installed.
While some customers feel they get better results with a wide angle lens, most have decided that it’s not necessary and that they can scan the entire cabinet by rotating a camera and standard lens. This is the safest, quickest, and most practical way to perform electrical cabinet inspections.