2 What is an fault arc - Die BG ETEM

4 Arc thermal risk parameters and their evaluation
Essential definitions and terms are summarized in Annex 2.
4.2 Calculation and measurement of thermal risk parameters
In the standardized electric arc test methods copper calorimeters are used to measure
the incident energy. The maximum value of the temperature rise dTmax of the defined
calorimeter copper disc (delta peak temperature) is proportional to the incident
energy Ei (see Figure 4.1):
with
14
Ei =
m . cp
A
. dTmax
m – mass of calorimeter copper disc
A – cross sectional area of calorimeter copper disc
cp – specific heat capacity coefficient of copper
dTmax – delta peak temperature (maximum temperature rise) of the calorimeter.
The delta peak temperature is the difference between the maximum temperature
during the test exposure time of 30 s and the initial temperature of the sensor.
Fig. 4.1: Temperature rise course during an arc test (example with sensor 1 directly exposed and
sensor 2 behind PPE)