Table of Contents
Advertisement
Chapter 12 Helpful information
5. 4 Pole (4P) MCB: A 4 pole MCB is similar to TPN but additionally it also has protective
release for the neutral pole. This MCB should be used in cases where there is possibility
of high neutral current flow through the circuit as in cases of an unbalanced circuit.
D Curve Circuit Breaker
Attention! This chapter is provided as reference and explanation. Always follow all national and
local electrical codes and laws of your country!
A miniature or molded - case circuit breaker (MCB) is an automatically operated electrical
switch designed to protect an electrical circuit from damage caused by over-current or
overload or short circuit. Its basic function is to interrupt current flow after protective relays
detect a fault.
DIN EN 60898-1 (VDE 0641-11):2006-03 stipulates per chapter 9.10.2.4:
A current equal to 10 In is passed through all poles starting from cold. The opening time must not be
less than 0.1 s or not more than
•
4 s for rated currents above 10 A up to and including 32 A,
8 s for rated currents up to and including 10 A and above 32 A
•
After this test a current equal to 20 In is then passed through all poles, again starting from cold. The
circuit-breaker must trip within 0.1 s.
Furthermore the circuit breaker must be tested according to chapter 9.10.1.2 of DIN EN 60898-1 (VDE
0641-11):2006-03.
Note that these tests are to be carried out in a controlled environment.
Please check with your local electrical standards body for further information on circuit breaker
testing.
These MCBs are use in industrial / commercial uses where current inrush can be very high.
Low-voltage circuit breakers
Low-voltage (less than 1,000 V
application, and include:
Miniature circuit breaker (MCB) - rated current not more than 100 A. Trip characteristics
normally not adjustable. Thermal or thermal-magnetic operation.
6U Rack or Tower UPS RT8kVA and RT11kVA IUOMG
) types are common in domestic, commercial and industrial
AC
199
Advertisement
Table of Contents
