Moulded Case Circuit Breakers (MCCB)
A moulded case circuit breaker (MCCB) protects feeders and equipment from around 16A up to roughly 2500A inside a sealed insulated case, sitting between an ACB upstream and MCBs on final circuits downstream. NLS Power sources MCCBs to IEC 60947-2, with thermal-magnetic or electronic trip units, sized to each feeder's load and fault current.
The moulded case circuit breaker fills the middle of the distribution chain, protecting individual feeders on an MDB or SDB and outgoing ways on an MCC, at current ratings from around 16A up to roughly 2500A depending on frame size. Its defining feature is the sealed, moulded insulating case around the whole mechanism, which makes it compact, low maintenance, and cheaper per amp than an ACB, at the cost of the field adjustability and higher current range an ACB offers.
Trip units come in two families. Thermal-magnetic breakers use a bimetallic strip for overload protection and a magnetic element for instantaneous short circuit trip, fixed by design or adjustable within a narrow band, and remain the standard choice for straightforward feeder protection where fine coordination isn't critical. Electronic trip units, standard on larger frame MCCBs and increasingly common across the range, add adjustable long-time, short-time and ground fault settings similar to an ACB's LSIG protection, which is what a project needs when several MCCBs feed from the same upstream breaker and have to trip in the right order during a fault.
Breaking capacity again has to be checked against the actual fault level at the point of installation, and it's worth noting explicitly that fault current drops the further a breaker sits from the transformer, so an MCCB on a top floor SDB genuinely needs less breaking capacity than one at the main switchboard, provided someone actually ran the calculation rather than specifying the same Icu everywhere out of caution.
MCCBs are available fixed-mounted, plug-in, or drawout depending on how often a project expects to swap or test the device, and current-limiting versions are specified where a downstream device's own rating needs protecting against a fault current higher than it could otherwise withstand.
NLS Power sources MCCBs to IEC 60947-2, thermal-magnetic or electronic trip, in the frame sizes and breaking capacities a feeder schedule specifies. Quoting works from the current rating and fault level per feeder; NLS Power returns pricing in USD, and because MCCBs are a widely stocked component across manufacturers, lead times are typically shorter than for ACBs or full switchgear assemblies.
Specifications
- ✓To IEC 60947-2, low voltage moulded case circuit breaker standard
- ✓Current ratings from approximately 16A to 2500A depending on frame size
- ✓Thermal-magnetic trip for standard feeder protection, electronic trip for adjustable coordination
- ✓Breaking capacity (Icu) verified against fault level at the specific point of installation
- ✓Fixed, plug-in, or drawout mounting options
- ✓Current-limiting versions available where downstream equipment needs fault current restriction
Frequently Asked Questions
What current range does an MCCB cover?+
MCCBs typically cover from around 16A up to roughly 2500A depending on frame size, sitting between MCBs on final circuits and ACBs at the main switchboard in a project's protection chain.
Who supplies MCCBs for panel builds in Saudi Arabia?+
NLS Power sources MCCBs to IEC 60947-2, thermal-magnetic or electronic trip, sized to each feeder's current rating and the fault level confirmed at that point on the board.
Do all MCCBs on a board need the same breaking capacity?+
No. Fault current drops the further downstream a breaker sits from the transformer, so a board's outgoing MCCBs can often carry a lower Icu rating than the incoming device, provided that's confirmed by calculation rather than specified uniformly out of caution.