My Cub Scout Training Solves Test Equipment Corrosion Problem

Quote of the Day

A man's intelligence does not increase as he acquires power. What does increase is the difficulty in telling him so.

— D. Southerland

Figure 1: Connectors Damaged Because of Water Ingress.

We have recently experienced some laboratory failures during humidity testing that were due to corroded connectors (Figure 1). The connectors had corroded after they become wet from condensation that accumulated on the cables and rolled down to the lowest point on the cable – where the connectors were.

Our testing is performed in environmental test chambers – essentially a combination of oven and refrigerator. We can adjust the both the temperature and humidity within the chambers. To connect the electronics inside the chamber to external test equipment, the cables pass through a hole in the chamber wall (Figures 2 and 3) called the pass-through. The condensation occurs when air leaking through the pass-through hole encounters the outside air.

While we try to seal the cable pass-through, some water inevitably condenses on the cables. Since the cable are hanging, the condensed water runs down the cables until it met a connector and corrosion can start.

Figure 2: Example of an Environmental Chamber with Side Cable Access.	Figure 3: Typical Internal Cable Configuration.

This situation reminds me of what I had to deal with as a Cub Scout when we would use  ropes tied to trees to hold up tarps and hammocks (Figure 4). When it was raining, water would run down the ropes and make the hammocks and tarps wet. The solution was to tie a drip line onto the ropes to interrupt the flow of water. It looks like the same solution will work for our environmental test cables.

Figure 4: Cub Scout Drip Line (source).