Why process plants are especially hard on electrical control cabinets
Corrosion is slow; safety is unforgiving. A cabinet can look fine for two years and then fail an insulation test — and a system that puts emergency shutdown in software will not pass a functional safety review. These are the four problems we focus on.
Corrosion comes from the air, not from splashes
Chlorine, hydrogen sulfide and acid mist attack powder-coated steel and unprotected copper busbar from the outside in. By the time it shows on the surface, the terminals inside are long gone.
Shutdown path depends on a PLC
If emergency shutdown runs through software, a processor failure is a safety failure. Auditors want an independent hardwired path, plus a cause-and-effect matrix.
Documentation does not survive an audit
Process plants run on traceability: material certificates, component traceability, test records, as-built drawings that match what was shipped. One missing item can hold up handover longer than it took to build the cabinet.
Explosion-proof scope gets assumed wider than it is
Hazardous area classification is often based on assumption rather than a defined scope. A cabinet described as suitable for a hazardous area without a stated protection type is a liability for both buyer and seller.
How we fight corrosion — and how we pass an audit
Four decisions, matched to the four problems above. Where something is beyond our capability, we state it at quotation stage, not after the order is placed.
| Design decision | What changes in the cabinet | How to verify |
|---|---|---|
| Atmospheric corrosion | Material selection comes first: 316 stainless steel for chemical and coastal atmospheres, 304 for general wet areas, powder-coated carbon steel only where the environment genuinely allows it; sealed gland plate at the bottom, foamed door gasket, phosphated pretreatment on coated parts, then 60–80μm topcoat. | Enclosure material certificates and coating thickness records go into the order file. |
| Software-dependent shutdown | Emergency shutdown is built as a hardwired chain — relays and contactors, not a PLC — with software interlocks layered on top, not underneath. | Cause-and-effect matrix and ESD loop drawings delivered with the drawings. |
| Audit documentation | Complete as-built package: schematic diagrams, terminal and wire number schedules, BOM with brand and model, routine test reports, and IP and CE declarations where applicable. | Each cabinet is numbered individually, and test records are filed under that number. |
| Explosion-proof scope | Here is where we draw the line: we do not build Ex-qualified enclosures ourselves. For hazardous areas, we quote certified components combined with pressurization or isolation solutions. What we cannot do, we decline outright — we never imply certifications we do not hold. | Every quotation includes a written scope statement — no language that implies certification. |
Equipment and applications we have built in this category
Process industries are one of our core focus areas, with delivered electrical packages across six categories of plant. We have documentation and photos for petrochemical; the rest are delivery records we can discuss in terms of approach — no customer site photos, no invented project figures.
Packaged solutions for chemical, petrochemical, pharmaceutical and process industries
These are the equipment and approaches we have built in this category. Each package page covers the duty conditions, the problem, how the cabinet is configured, and what can be customized per project.
Petrochemical plant control cabinet
Corrosive atmospheres and classified zones in plant areas: zone-based supply paths, corrosion-resistant enclosures, interlock configuration.
See this package →Chemical / reaction / heat transfer equipmentChemical equipment control cabinet
Data acquisition and control for reactors, heat exchangers and similar equipment: analog isolation, split-range PID, hardwired interlocking.
See this package →Fertilizer / urea processesUrea separation unit control cabinet
Temperature control and valve sequencing for separation stages: programmed to the process step table, shipped after factory simulation testing.
See this package →Pharmaceutical / GMP equipment packagesPharmaceutical equipment control cabinet
Enclosure construction and surface finish for GMP environments, verifiable process records, CIP sequence interlocking.
See this package →Air separation / cryogenics / industrial gasesAir separation unit control cabinet
Data acquisition and interlocking for compression, pre-cooling, purification and distillation stages, with DCS integration support.
See this package →Reactors / electric heating packagesReactor heating jacket control cabinet
Zone-based temperature control and power regulation for heating jackets, with independent hardwired over-temperature trip per zone, shipped after full-power burn-in.
See this package →Three cabinet types for process plants
Most chemical sites need corrosion-resistant control cabinets, safety interlock cabinets, and instrument signal marshaling cabinets.
316 stainless steel corrosion-resistant control cabinet
- Enclosure316 or 304 stainless steel, IP65, sealed gland plate at the bottom
- Control systemSiemens / Mitsubishi PLC with HMI
- ProtectionFoamed door gasket, anti-condensation heater, exposed stainless steel hardware
- DocumentationMaterial certificates and coating thickness records available on request
Interlock and emergency stop control cabinet
- SafetyHardwired ESD chain, independent of the PLC
- DocumentationCause-and-effect matrix and loop diagrams
- IndicationAlarm annunciator panel or touchscreen alarm page
- StandardsIEC 61439-1/-2 · CE (LVD + EMC)
Instrument junction and terminal boxes
- FormatWall-mounted, IP65, 24–96 circuits
- SegregationIntrinsically safe and non-intrinsically safe circuits in separate compartments
- MarkingTerminal numbering matches the loop diagrams
- Material316 stainless steel or powder-coated steel
Photo evidence: complete unit, interior and industry-specific details
The three slots below are photo positions for cabinets in this industry. We have built for these duty conditions, but site photos have to be collected project by project; placeholders are used until then, with a brief under each. Replace once photos arrive — no customer or project is identified on the page.
From drawing to shipment, in five steps
316 stainless steel sealed cabinet, PLC with touchscreen, hardwired ESD chain, instrument and power wiring routed separately, terminal numbers matching the loop diagrams, full routine testing completed before shipment and a complete as-built documentation package delivered.
01 Send drawings & duty conditions
Send the single-line diagram / load list / protection requirements / quantity. Quote within 1 working day.
02 Drawing review
An electrical engineer verifies the selection item by item, with a call if circuit details need clarifying, and issues a revised schematic.
03 Order & scheduling
Delivered 15-25 days after scheduling begins; urgent orders can take a fast track (volume plus stock components).
04 Factory testing
Every unit gets a powered functional test + 2500 V·1 min withstand + ground continuity + IP sampling.
05 Dispatch & acceptance
Finished-cabinet photos and routine test records before dispatch; the full documentation pack travels with the cabinet so commissioning can start on arrival.
Chemical, Petrochemical, Pharma & Process control cabinets
Corrosion-resistant control cabinets custom-built for chemical, petrochemical, pharmaceutical and air separation plants: 316 stainless steel enclosure, sealed gland plate at the bottom, hardwired ESD chain independent of the PLC, complete as-built documentation package, compliant with IEC 61439 and CE, delivered in 15–25 days.
Industry FAQs
Do you build Ex / ATEX certified cabinets?
We do not build Ex-qualified enclosures ourselves, and we will not imply that we can. For hazardous areas we evaluate each order individually, using certified components and pressurized or isolated designs; where something is outside our scope, we will say so plainly.
Should I use 304 or 316?
It depends on the environment. For general wet areas, 304 is sufficient; where there are chloride ions, acids or coastal salt spray, use 316. Tell me what is in the air at the site and we will specify honestly, including telling you where powder-coated steel is enough.
Can the emergency stop work without relying on the PLC?
Yes, and we recommend it. The ESD chain is hardwired through relays and contactors; the PLC only handles interlocking and alarm display. We provide the cause-and-effect matrix so your review team can verify the logic.
What documentation comes with the cabinet?
As-built schematic diagrams, terminal and wire number schedules, BOM with brand and model, routine test reports (insulation, power frequency withstand, grounding continuity, powered functional test), IP and CE declarations where applicable, and factory photos.
Can you install instruments we supply ourselves?
Yes. We routinely design around customer-supplied transmitters, analyzers and safety relays. Send the list along with your delivery schedule and we will flag which items affect the timeline.
Are there special requirements for pharmaceutical or food cleanrooms?
We can build to your requirements: easy-clean surfaces, no dust-trapping structure, exposed stainless steel parts, silicone gaskets. The specific cleanliness class and certifications are defined by your process; we build to drawing and do not invent certifications.
The other eight categories
Water & Environmental →
Industry #02Mining, Tunneling & Heavy Machinery →
Industry #03Municipal Infrastructure & Smart City →
Industry #04Energy & Power Generation →
Industry #06Building & Facility Power →
Industry #07Logistics, Warehousing & Sorting →
Industry #08Marine & General Equipment OEM →
Industry #09New Energy (PV · Storage · EV Charging) →
Tell us about your plant and area classification
Selecting cabinets for corrosive or safety-critical areas?
Honest scope review · Quotation approach the same day · We tell you straight when something is beyond our scope