Arc Flash and Power Studies in the Houston Area

What Houston-area systems look like

Four of these sites take utility service at medium voltage. The terminal near Houston and the Galveston campus each take 12.47 kV, the Humble plant 34.5 kV and the technology campus 35 kV, which a single transformer steps down to 4.16 kV for its substations. The federal campus has two utility feeds, each through a 3,000 kVA transformer, backed by two standby generators.

At the federal campus, tie breakers, transfer switches and a UPS bypass mean the same bus can be fed in several ways, each with a different fault current. Our models for the federal campus, the technology campus, the Humble plant and the terminal each carry six operating scenarios, and at the federal and technology campuses every label uses the worst case for its bus.

Where the energy is high

The final Galveston campus model had 53 locations above 40 cal/cm² on utility power, the highest near 139. At the Humble plant, 19 locations across two buildings came out above 40, the highest about 128 cal/cm² at a 3,000 A switchboard. At those levels the reports put de-energized work first. At the federal campus, where no breaker setting change could bring the energy down at the utility and standby generator buses, the report recommends arc flash protection at a future upgrade: a light-sensing system that trips a shunt-trip breaker, or relays with arcing fault detection.

Keeping studies current

NFPA 70E^® calls for the incident energy analysis to be reviewed at least every five years and whenever the system changes. Several Houston-area owners have had us back for that. The federal campus study from 2019 was updated in 2024, and the technology campus and Humble studies from 2020 were updated in 2025. In those five years the technology campus model grew from 318 buses to 445.

More than the label

Some studies come with more. At the terminal, the arc flash study came with a motor starting study for the new motor control centers and a harmonic study at both utility connection points. At the Pasadena chemical plant we scanned the motor control centers and switchgear with an infrared camera, found an incoming line terminal running about 75°F hotter than the others on its breaker, and later tested the plant grounding point to point.