Breaker housings
MCB, RCCB, MCCB and ACB housings, bases and covers.
For breaker makers
Custom plastic mouldings, made to your drawing.
Injection and compression moulded parts in engineering thermoplastics and thermosets, from MCB, MCCB and ACB housings to the parts inside. Manufactured in India, inspected against your drawing, and delivered to your Incoterm.
- Thermoplastics and thermosets
- Flammability class to spec
- Measured records
MCB housing half, PA66 GF30, V-0DWG REV. D
- Material
- PA66 GF30, UL 94 V-0
- Process
- Injection moulded
- Critical dimension
- Length 81.00 ±0.10 mm
- Inspection
- Critical dimensions measured
What we make
Breaker internals
Handles, trip levers, cams, latches and arc chamber parts.
For the mechanism inside the breaker
Contactor and relay parts
Bases, covers, armature carriers and coil bobbins.
For contactors and relays
Terminal block bodies
Insulating bodies, end plates, jumpers and markers for DIN rail terminal blocks.
For terminal block makers
Insulators and busbar supports
Supports, standoffs, barriers and spacers in DMC, SMC and glass-filled plastics.
For switchgear and busduct
Insert and over-moulded parts
Metal terminals, inserts and coils moulded into the plastic part.
For fewer parts and joints on your line
Choosing a material
Heat, flame and tracking decide the plastic. The shape and the volume decide the process.
Thermoplastics injection moulded
- Polyamide, glass filled PA66, PA6
- Strong and tough, for housings, handles and internals.Watch for: Absorbs moisture and grows slightly; state whether dimensions are dry or conditioned.
- PBT, glass filled
- Stable dimensions and good tracking resistance, for terminal blocks and relay bases.Watch for: Less tough than polyamide under impact.
- Polycarbonate PC
- Clear and impact strong, for covers, windows and indicators.Watch for: Cracks under stress with some greases and solvents.
Thermosets compression or transfer moulded
- DMC and BMC polyester
- High heat and arc resistance, for MCCB and ACB housings and arc chambers.Watch for: Flash must be removed; edges chip if handled roughly.
- SMC
- Large, flat, stiff parts: busbar supports, barriers and panels.Watch for: Thickness varies more than in injection moulding.
- Melamine and phenolic
- Arc resistant, found in arc chutes and older designs.Watch for: Give the grade; colour and properties vary.
Fire and tracking for the standard
- UL 94 rating V-0 to HB
- How the plastic burns and self-extinguishes.Watch for: The rating holds at a thickness; give the thinnest wall.
- Glow-wire IEC 60695-2
- Resistance to ignition from an overheated part, as GWFI and GWIT.Watch for: Name the temperature, such as 750 °C or 850 °C, on the drawing.
- Tracking index CTI, IEC 60112
- Resistance to tracking across the surface under voltage.Watch for: It sets the creepage distances under IEC 60664.
Specifications
- Types
- Breaker housings; breaker internals; contactor and relay parts; terminal block bodies; insulators and busbar supports; insert and over-moulded parts
- Thermoplastics
- PA6 and PA66, unfilled and GF15–GF50; PBT GF; PC; PC/ABS; PP; PPS
- Thermosets
- DMC and BMC; SMC; melamine; phenolic
- Processes
- Injection, insert and over-moulding; compression and transfer moulding
- Machine size
- 50–450 tonnes standard
- Flammability
- UL 94 V-0 to HB; glow-wire to IEC 60695-2-12 and 2-13; CTI to IEC 60112, as specified
- Colours
- To RAL or your master batch
- Checks
- Critical dimensions; material grade with certificate; flammability class; visual to your limit sample
- Quantities
- Prototype builds to mass production
Thermoplastic or thermoset
Thermoplastics mould faster. Thermosets stand up to heat and arcing.
Thermoplastics
Injection moulded in seconds, with fine detail and snap fits. PA66, PBT and PC.
Choose it for housings, internals and terminal blocks at volume.
Thermosets
Compression or transfer moulded and cured. Do not soften when hot, and resist arcing. DMC, SMC, melamine and phenolic.
Choose it for MCCB and ACB housings, arc chambers and busbar supports.
- Heat
- Thermosets keep their shape when hot. Thermoplastics soften above their rated temperature.
- Arc and tracking
- Thermosets and filled PBT resist arcing and tracking best.
- Cycle time
- Thermoplastics mould faster, so cost less per part at volume.
Questions buyers ask
Which plastic is used for MCB housings?+
Usually glass-filled PA66 or PA6, or glass-filled PBT, rated UL 94 V-0 with a glow-wire rating to suit IEC 60898. MCCB and ACB housings often use DMC or other thermosets for heat and arc resistance.
What is a glow-wire test?+
A heated wire is pressed against the plastic to show whether it ignites, and whether flames go out. The glow-wire flammability index, GWFI, and ignition temperature, GWIT, are tested to IEC 60695-2-12 and 2-13.
What does UL 94 V-0 mean?+
A test bar of the plastic stops burning within 10 seconds and drips no flaming particles. The rating applies at a stated thickness, so it must hold at the thinnest wall of your part.
Can you mould our metal parts into the plastic?+
Yes. Terminals, inserts and coils can be insert moulded or over-moulded, so you receive one part instead of several. The metal parts can come from us too.
Can you match an existing moulding from another supplier?+
Yes. Send the drawing, and a sample if the drawing is incomplete. We tell you what can be held before we quote, then make samples for your approval.
Can you take a small order?+
Yes. Small, engineering-heavy batches are work we take, from prototype quantities upwards.
Send the drawing
Email us your enquiry at contact@qumek.com. We respond within 12 hrs.
Your enquiries are confidential with us and we proceed with manufacturing only after signing a NDA.
Need a DFM review, a prototype or a test plan before production? See the services.