Field terms, plainly

What’s on the pipe,
and what protects it

EHT — Electric Heat Trace

The general term for electrically powered heating cable systems that maintain pipe temperature. Covers every cable type and technology in this glossary.

Self-Regulating Cable

Heat trace cable that adjusts its own power output to the temperature of the pipe it’s on — the default choice for freeze protection, since it draws less as the pipe warms.

Constant Watt Cable

Heat trace cable that delivers a fixed watt-per-foot output regardless of temperature. Used where self-regulating cable can’t hold a high maintain temperature.

MI Cable — Mineral Insulated

Stainless-sheathed copper conductors in compressed mineral-oxide insulation — the cable for extreme temperatures, classified areas, and safety-critical circuits, with a sheath that’s weld-repairable.

GFEP — Ground Fault Equipment Protection

A breaker-level protection scheme, commonly tripping at 30mA, that takes a circuit offline when it develops a ground fault. Required by NEC Article 427.22 for electric heat-tracing branch circuits; IEEE 515 covers the testing practice.

Ground Fault

An unintended path where current leaves its normal circuit — through moisture, a crushed cable, or damaged insulation — and finds a route to ground instead of returning the way it’s supposed to. The condition GFEP is built to catch.

Setpoint

The temperature a thermostat or controller is programmed to hold or trigger at. A setpoint drifted a few degrees off design still looks correct on the panel — and stays invisible until the pipe it protects gets cold enough to prove it wrong.

What an auditor, an insurer,
or the next contractor needs

Panel Schedule

A document listing every heat trace circuit in a system — circuit number, load in watts, breaker size, thermostat setpoint, and the pipe or zone it serves. The reference every troubleshooting call starts from.

As-Built (Drawings)

What was actually installed, as opposed to what the design drawing intended — re-routed runs, relocated junction boxes, circuits combined or dropped. Only one of the two is true, and it isn’t the one issued before the work started.

Closeout Package

The documentation that keeps working after the crew is gone — as-builts, panel schedules, circuit-level test records, setpoint sheets, and the commissioning report, all tied to what was actually installed and tested.

NERC EOP-012 — Cold Weather Reliability Standard

The North American Electric Reliability Corporation standard requiring generating facilities to identify cold-weather-critical components, verify freeze protection against each unit’s cold weather temperature threshold, and document it. Hard implementation deadline: October 1, 2027.

ECWT — Extreme Cold Weather Temperature

The coldest temperature a generating unit is required to be prepared for under NERC EOP-012 — the threshold that determines which components carry a cold-weather-critical designation.

CWCC — Cold Weather Critical Component

A NERC EOP-012 designation for equipment whose failure at or below a unit’s Extreme Cold Weather Temperature could keep the unit from starting or staying online — the components a corrective action plan is built around.

PSM — Process Safety Management

OSHA’s regulatory framework for facilities handling highly hazardous chemicals. Heat trace systems in PSM-covered facilities need documented design, installation, and maintenance records as part of the Mechanical Integrity program.

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