Infrared Scans and a Point-to-Point Grounding Assessment at a Chemical Plant, Pasadena (2020-2021)

In 2020 and 2021 we scanned the electrical equipment of a chemical plant in Pasadena, Texas, with an infrared camera, and in 2021 we assessed its grounding system point to point. Client details are confidential.

Motor controllers in one of the electrical rooms scanned in 2020. The scan covers every section, front and back, not only the ones that look suspect.

Scanning every bucket

The 2020 scans covered the plant motor control centers, front and rear, and its switchgear bus sections. Each bucket and section got its own report sheet, filed under normal, abnormal or off, so the plant can find any item and compare it with the next year. Each terminal is scanned by the technician. When nothing stands out, an overall image is still saved, and it records the hottest object in the device at the time.

A terminal that could not wait

During the March 2021 scan, one bucket of a motor control center showed very high temperatures on one phase of its incoming line terminal. That terminal ran about 75°F hotter than the other terminals on the same breaker, and about 100°F hotter than an identical breaker serving a parallel system. In our opinion it presented an immediate danger of fire in that electrical room. Once a termination gets that hot, corrosion speeds up, resistance rises and the heating feeds on itself. Our contact at the plant was told on the spot, and plant personnel decided to repair it right away. Once the plant was in a safe state, the repair was made with their help, and an after-repair image confirmed the result. The 2020 overall image of the same bucket had shown no problem.

The grounding assessment

In September 2021 we tested the plant grounding system by the point-to-point method. Using fourteen record grounding drawings, covering the process, distillation, treatment and storage areas, the control buildings, the expansion areas and the main substation, the crew connected a reference riser in each area and ran a 250 foot spool of wire to every other riser they could reach. A Fluke^® 1625-2 measured the resistance between each pair, with the spool and lead resistance taken into account. A point-to-point resistance of 1 ohm or less was considered adequate. Many test points on the drawings could not be found in the field, a sign of changes since the drawings were last updated.

What the testing found

Three items were critical. One test point on the substation fence was discontinuous and needed a new bonding jumper. On two tanks, the grounding riser was not attached to the tank at all. A fourth item was a recommendation: at one control building, a non-conductive coating between an air-cooled condensing unit case and its ground lug was preventing good contact. Each is a simple fix once someone knows where to look.

Plant electrical surveys

The scanning service is described on our page for infrared inspections. The testing is described on our page for grounding system tests.