MCCB for line protection — 20 A, 4-pole, TM210 trip
The TM210 thermal-magnetic release provides fixed overload and short-circuit protection — no adjustable thermal pickup, so the trip curve is set at the factory for the 20 A frame. Interrupting capacity reaches 75.6 kA at 240 V and 52.5 kA at 415 V, giving selectivity headroom in high-fault panelboards.
The 20 A rating holds through 55 °C ambient; above that, derate to 19 A at 60 °C through 70 °C. This matters for tightly packed panels where internal temperature rise can push past 55 °C — a 5 % reduction avoids nuisance tripping. Maximum power loss is 12 W per pole — a figure to factor into enclosure thermal calculations when grouping multiple breakers.
Interrupting ratings across voltages
The breaker's interrupting capacity varies with system voltage: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V. On a 400 V class panel, the 52.5 kA figure covers most utility transformer secondary faults.