Fault level is arithmetic
Clearance, then height
Built in Bintulu
Documents are a deliverableFault level is a calculation, not a preference
The short-circuit withstand of the assembly and the breaking capacity of the devices must cover the prospective fault current at that point in the installation. This is arithmetic, it is done from the transformer rating and impedance, and it is the single most common thing found wrong on a panel that was bought on price.
Worked through: a transformer's prospective short-circuit current at its secondary is approximately its rated current divided by its percentage impedance. A 2,500 kVA transformer at 6 % impedance produces roughly 55 kA at the secondary terminals. A board specified with 50 kA devices on that supply is non-compliant on the day it is installed, regardless of how well it is built, and no amount of workmanship corrects it.
What follows from that calculation: device breaking capacity, busbar bracing, the form of separation, and whether cascading or a current-limiting upstream device is being relied on. If it is, that dependency has to be documented, because a future change upstream silently invalidates it.
Sizing for drives and heat
An enclosure carrying variable speed drives is sized by thermal behaviour, not by the footprint of the components.
- Height is the drive body plus the manufacturer's stated airflow clearance, above and below, for every drive in the stack. Show that sum on the drawing. A clearance quietly absorbed to make a layout fit produces thermal trips that get diagnosed as drive faults for months.
- Heat load is calculated from the losses, drive by drive, plus the ambient the switchroom actually reaches in the afternoon, not the ambient on the datasheet.
- Cooling is specified from that number. Natural ventilation, forced ventilation, or air conditioning, with filters that somebody is actually going to change.
- Incoming on the left, load out to the right, as a house convention, because a consistent layout is what lets an unfamiliar technician work safely at two in the morning.
IP rating follows the location, not the catalogue. A dusty conveyor gallery, a washdown area and an air-conditioned switchroom are three different enclosures. Over-rating costs money and makes the thermal problem worse, because a sealed enclosure cannot ventilate.
What we build
- PLC and control panels, including marshalling and remote I/O cabinets
- Motor control centres and starter boards, fixed and withdrawable
- Drive panels, single and multi-drive, with the thermal design shown
- Operator consoles and control desks, including console rebuilds around existing equipment
- Field junction boxes and local control stations, to the area classification of the location
Every assembly ships with wiring schedules, a tested functional check against the schematic, a torque record on power terminations, and as-built drawings. The document pack is the part you still have in five years, so it is treated as a deliverable rather than an afterthought.
Built in Sarawak, for Sarawak sites
Our fabrication base is in Bintulu, which matters more than it sounds for a panel. A panel is bulky, it is easily damaged in transit, and it almost always needs a modification once it meets the site. When the build is local, a site change is a short drive and a day. When it is not, it is freight, a barge schedule and a fortnight.
It also means the people who wired the panel are the people who commission it, and they are reachable when something needs attention a year later.
Questions we get asked
Can you modify an existing panel rather than building new?
Frequently, and it is usually the cheaper answer. The limits are the busbar rating, the fault level of the existing assembly and whether there is genuine thermal headroom. All three get checked before we agree, because a modification that exceeds any of them transfers a compliance problem to whoever signs it off.
How do you decide the enclosure size?
From the thermal calculation and the stated clearances, then the component layout, then the ingress rating for the location. Working in the other order is how panels end up too small in exactly the way that cannot be fixed later.
Do you deliver and install, or just build?
Both. Build, deliver, install, terminate, test and commission, with a local crew for Sarawak sites.
What documentation comes with a panel?
As-built schematics, wiring and terminal schedules, component list with part numbers, test records including the functional check and termination torque record, and the operating and maintenance information for the major components.