ARM5 Series 630A 3Pole Molded Case Circuit Breaker with High Breaking Capacity MCCB

85kA at 400V is the floor for the series, not the ceiling—the H version pushes that to 200kA, which is frankly overkill for a standard distribution board but essential for transformer feeders or heavy motor circuits with high fault currents. We’ve had buyers spec the L version for a 400A feeder and then realize they need the M for the 50kA fault level at main switchboard, so check your utility’s short-circuit calculation before ordering—roughly 30% of returns we see are form mis-matched breaking capasity.

What it’s not suited for is frequent switching under load; with a mechanical life of 10,000 operations and electrcial life at 7,000, it’s a protection device first and an isolation switch second. The arc extinguishing is air-based with magnetic blowout channels, and at 690V you’ll get a distinct pop when it trips—that’s the ionized gas being forced out the vents, and we usually tell people to keep a 100mm clearance above the breaker in the panel for that.

The insulation voltage sits at 1000V with a 12kV impulse withstand, so it’ll handle the transients from a nearby lightning strike or capacitor bank switching without flashover—something a lot of cheaper MCCBs can’t guarantee at the 690V rating. Dimensoins on the 3-pole are 140mm wide by 255mm tall by 169mm deep, weighing about 5.8kg, and it’s manual operation only (no motor operator as standard, though you can add one aftermarket if you really need remote trip).

Protection functions cover overload (thermal-magnetic, adjustable), short circuit (magnetic, non-adjustable), and under-voltage (add-on module required, not built-in), and the trip unit is basically the same across the L, M, and H variants—the difference is solely in the contact materials and arc chamber geometry to handle higher fault currents. You’ll get ISO9001 and CCC certs with each unit, and we include a COA (usually 2-3 pages) showing the actual Icu test results for that batch.

MOQ is typically 5 units for the 630A frame, but our company can do singles if you’re prototyping—lead time is about 20 days or so for the L version, longer for the H because the silver-tungsten contacts are sourced from a different supplier. Also, the 4-pole version adds about 35mm to the width and weighs 7.2kg, and it’s better than the 3-pole for generator incomers where you need to break the neutral as well.