Installation Manual

21
ElectroMelt System
Design Guide
Supplemental Design
Information
Example
An application at a parking garage requires four heating cable circuits 275 feet
long. The heating cable is to be powered at 277 Vac.
Circuit Breaker Sizing
From Table 1 on page 12, up to 300 feet of heating cable may be connected to
a single 50-amp branch circuit breaker.
Transformer Sizing
The branch circuit current after startup at 0ºF is calculated as follows:
Current = 80% x 50 amp/300 ft
= 0.13 amp/ft
Transformer size = 0.13 amp/ft x 275 ft/circuit x 277 Vac
= 39,600 watts
= 39.6 kilowatts