Form 4 Motor Control Centre for a Wastewater Treatment Works
R&R Engineering designed, manufactured and delivered a 69-way motor control centre for a wastewater treatment works, built in transportable sections and reassembled on site. A 630A 50kA withdrawable ACB incomer and Form 4 Type 7 internal separation sit behind a Profibus-networked control system driving VSD, star-delta and direct-on-line starter sections across the plant.
The completed motor control centre installed and commissioned on site.
Where it starts â bare cubicle frames on the build floor, before any gear is fitted.
630A
Busbar and Incomer Rating
Form 4
Type 7 Internal separation
50kA
Breaking capacity
69
Outgoing sections
THE PROJECT
The MCC provides motor control and protection for pumping, thickening, dewatering, polymer dosing, sludge handling and odour-control plant across the works, together with building services, site actuators, and level and flow instrumentation feeding the control system.
At 69 outgoing sections the assembly was too large to build or move as one piece. It was manufactured and pre-wired in individual sections at R&R’s facility, then transported and reassembled on site with R&R’s assistance, maintaining internal separation and busbar and control wiring continuity between sections.
THE SOLUTION
- Floor-standing Form 4 Type 7 cubicle with 630A 4P busbar system and 96 cable boxes, built in sections and transported to site for reassembly
- 630A 4P 50kA withdrawable air circuit breaker incomer (ABB SACE Emax 2, Ekip Dip LSI protection) with motorised mechanism and door escutcheon
- Socomec DIRIS A-30 energy meter with Profibus, mains CT metering, phase-failure and mains-failure monitoring, and brown-out restoration timing
- Type 1+2+3 50kA surge protection on the incomer
- 20 outgoing feeder sections, each fuse-switch protected with individual Socomec Diris A20 Profibus metering, covering process and building-services distribution
- 25 VSD starter sections from 1.5kW to 18.5kW, each door-interlocked and fitted with MiniCAS II motor protection and Profibus communications
- 12 star-delta and 12 direct-on-line starter sections, each with Siemens Simocode Pro motor management
- Instrumentation interfacing for 16 Siemens Hydroranger 200 ultrasonic level transmitters and 18 Siemens electromagnetic flowmeters, plus lightning protection for 30 valve actuators
- PLC common control section with a dual-hub Profibus network, 24VDC I/O relay banks and a Riello UPS with maintenance bypass
- Panel heaters, ventilation fans and filters fitted to every motor starter section
- Paired with wall-mounted local isolator and control stations at individual pump and dosing locations around the site
- Delivered to site in sections, reassembled and set into place with R&R's assistance
SPECIFICATION
- 1 x 630A 4P 50kA withdrawable ACB incomer (ABB SACE Emax 2, Ekip Dip LSI)
- 20 x 32A/63A TP fuse-switch outgoing feeder sections
- 25 x VSD starter sections, 1.5kWâ18.5kW
- 12 x star-delta and 12 x direct-on-line starter sections (Siemens Simocode Pro)
- 1 x PLC common control section, dual Profihub B5+ Profibus network, Riello UPS
PROJECT DETAILS
- Enclosure: Floor-standing steel cubicle, IP rating
- Scope: Design, manufacture, delivery and on-site reassembly
- Completed: 2026
THE OUTCOME
The completed MCC gives the works motor control and protection for pumping, thickening, dewatering, dosing and odour-control plant from a single Profibus-networked system, with fused and metered outgoing sections for individual monitoring and fault-finding. VSD, star-delta and direct-on-line starter sections use Simocode motor management for local protection and diagnostics, and a UPS-backed control section with dual Profibus hubs keeps the network resilient. Spare and future-duty sections leave capacity for the plant to expand without a further switchboard.
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