Tracing SC

Module from the Electrical Engineering Curriculum curriculum.

Module 10 - Heat Tracing and Short Circuit / Arc Flash · Learning Objectives · 1. Select self-regulating vs constant-wattage vs MI cable tracing · 2. Size tracing per IEEE 515 heat loss calculation · 3. Compute short-circuit current at each bus per IEEE 141 / ANSI C37 · 4. Perform arc flash study per IEEE 1584-2018 to set incident energy · 5. Specify appropriate PPE per NFPA 70E Table 130.7(C)(15) · Heat Tracing Types

Type	Max T (F)	Self-Limit	Cost	Maintenance	Use
Self-regulating	150-250 (varies)	Yes	Moderate	Low	Most refinery <250F
Constant wattage	350	No	Low	Medium	Fixed temp, longer lengths
Mineral-insulated (MI)	600-1200	No	High	Low	High-T, long-term
Skin-effect	300-450	No	Very high	Low	Long pipelines
Impedance	400	No	High	Medium	Special
NFPA 70E Arc Flash PPE Categories
Category	Incident Energy (cal/cm2)	Min Arc Rating	PPE Description	Typical Voltage	Notes
Cat 1	1.2-4	4 cal/cm2	AR shirt + pants + shield	LV panelboards	Basic
Cat 2	4-8	8 cal/cm2	AR coverall + hood	Feeders	Standard MCC work
Cat 3	8-25	25 cal/cm2	AR suit + hood	Switchgear	Standard MV
Cat 4	25-40	40 cal/cm2	AR suit + hood + gloves	Large switchgear	Use engineering controls if >40
Above Cat 4	>40	DANGER - no work	De-energize required	Extreme SC	NFPA 70E 130.2

Source: Electrical_Engineering_Curriculum_v1.xlsx · Sheet: Tracing SC

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