What Goes Into a Control Panel, and Why It Is Finished Before It Ships

A control panel is the one part of an automation system a client can walk around before it does anything. It is also the part most often judged by its front, which is a shame, because the front is the least interesting thing about it.

What matters is behind the door, and whether all of it was decided before the panel left the workshop.

What is actually inside

Strip a typical pumping station panel and the contents fall into three groups that have almost nothing to do with each other.

Power. The incomer, the main isolator, the busbar, the moulded case circuit breaker, the miniature breakers for the auxiliaries, and a starter or a drive for every motor. This is the part that gets hot, the part that decides the enclosure size, and the part with the long lead times.

Control. The PLC or RTU, its input and output cards, the interposing relays that keep field voltages away from the controller, the 24 volt supply and the UPS behind it, the ethernet switch, and the terminals where the site actually lands.

The operator. The HMI, the pushbuttons and lamps, the labelling, and the drawing pocket. This is the layer that decides whether the person on shift can tell what the plant is doing without calling anyone.

A panel is a good panel when those three groups are separated properly, routed properly, and labelled so a stranger can follow them at two in the morning.

Form 4, and why the separation is the specification

On the irrigation mains at Khalifa City "A" we built five motor control centres to Form 4, one per pumping station, alongside five PLCs, five RTUs, HMI touch screens and fifteen variable frequency drives across the pump sets.

Form 4 means busbars, functional units and outgoing terminals are each segregated from one another. It costs more steel and more labour than a lower form, and it buys exactly one thing: the ability to isolate a single starter and work on it while the rest of the board stays live. On a station feeding a district irrigation network, that is the difference between taking one pump out of service and taking the station out of service.

Clients rarely ask for Form 4 by name. They ask whether maintenance can be done without stopping. It is the same question.

The panels are not all the same size

The word panel covers a wide range in practice, and most of ours are small.

• Twelve pump control panels across parks for the Department of Municipalities and Transport, seven of them three phase at 5.5 kW and five single phase at 2.5 kW, each carrying an RTU and a connection back to SCADA.
• A VFD and instrumentation panel at the Shakhbout City parks and playgrounds, integrated into the existing irrigation SCADA rather than replacing it.
• A wall mounted RTU and PLC panel for the cycling club irrigation system on Hudariyat Island, with pressure transmitters, motorised gate valves and flow meters wired back to it.
• Full motor control centres and RTU cabinets on the larger pumping and grid work.

The engineering effort does not scale with the enclosure. A 2.5 kW single phase pump panel that has to survive a summer in an unshaded park, report to a control room, and be maintained by someone who has never seen it before, is not a trivial build.

Why it is finished before it ships

Every panel we build is assembled, wired, labelled and factory tested at our own workshop in Mussafah, and clients are welcome to witness that test before anything is loaded.

This is not a courtesy. A panel that arrives on site half finished turns installation into fabrication, in a building that was never designed to be a workshop, usually next to plant that is still running. Every hour of that work is more expensive and more dangerous than the same hour in Mussafah.

A factory acceptance test proves the wiring against the drawings, exercises every input and output, runs the control sequence, forces the alarms, and does all of it with the client's engineers in the room. What leaves afterwards is a finished assembly with a known state, so the site work is installation and commissioning rather than discovery.

The other reason is documentation. The as built drawings, the terminal schedules and the settings are produced while the panel is in front of the person who built it. Documented later, from memory, they are worth considerably less.

What we need from you to quote one

A useful panel enquiry is short. The motor schedule, or at least the ratings and the number of starters. Whether the drives are new or being reused. What the panel has to talk to, and over what protocol. Where it will physically stand, and whether that location is air conditioned. Whether there is an existing SCADA it must join or whether the supervisory layer is in scope too.

Everything else we can work out. Those five points decide the enclosure, the form, the lead time and most of the price.

Working with us

Almafor designs, builds, tests and commissions control panels for pumping, irrigation, water, power and building services across Abu Dhabi and the wider UAE, as main contractor and as a specialist subcontractor to other engineers. Panels are built and factory tested at our workshop in Mussafah.

Call +971 55 954 5801 or email info@almafor.com with the motor schedule and we will come back with a scope rather than a brochure.