Technical data

www.westermo.com Theoretical and general applications 23
1.8 Flammability
UL 94 The Standard for Flammability of Plastic Materials for Parts in Devices and
Appliances
… Methods to measure and describe the characteristics of specimen materials relating
to flammability, when exposed to heat and flames under controlled forms in a labo-
ratory environment.
2 Definitions
2.1 Rated voltage range
… Voltage range specified by the manufacturer.
2.2 Operating voltage range
… Voltage range within which the device, under the specified conditions, can perform
its intended functions. Rated voltage range and upper and lower tolerances.
2.3 SELV
… A secondary circuit which is so designed and protected that, under normal and sin-
gle fault conditions, its voltages do not exceed a safe value.
2.4 TNV-1
… A secondary circuit whose normal operating voltages do not exceed the limits for a
SELV circuit under normal operating conditions and where overvoltages from
telecommunication networks are possible.
2.5 TNV-3
… A secondary circuit whose normal operating voltages exceed the limits for a SELV
circuit under normal operating conditions and where overvoltages from telecom-
munication networks are possible.
B A C K