Instrument protection boxes
- Insulation: 30–50 mm rock wool sandwich layer; winter duty sized against the local minimum temperature
- Heat tracing: self-regulating electric heat tracing cable, standard optional / steam tracing pipe to drawing
- Rain protection: rain hood projecting ≥50 mm, double door-frame seal, bottom drain holes
- Material: SPCC cold-rolled steel standard / 304 stainless steel (coastal and chemical areas)
- Layout: one instrument per enclosure / multiple instruments per enclosure; mounting plates and impulse line connections to drawing
Specifications
The table below covers 80% of factory distribution room cases. Anything outside it we can still build — those are engineered items, quoted separately, with an indicative price the same day.
| Standard sizes (W×D×H) | 400×300×500 / 500×400×600 / 600×500×800 mm; multi-instrument enclosures to drawing |
|---|---|
| Material | SPCC cold-rolled steel (standard) / 304 stainless steel (coastal, chemical areas) |
| Insulation | 30 / 50 mm rock wool sandwich layer, lined with 0.5 mm galvanized sheet |
| Rain protection design | Top rain hood projecting ≥50 mm, double door-frame seal strip, bottom drain holes |
| IP rating | IP65 (GB 4208 / IEC 60529) |
| Installation | Pole clamp / wall-mount bracket / platform railing clamp-on |
| Impulse line connection | Side / bottom conduit ports φ22–φ34 to drawing, with sealing grommets |
| Surface finish | SPCC powder-coated (outdoor: hot-dip galvanized + dual coating) / 304 brushed stainless |
| Electric heat tracing | Self-regulating heat tracing cable 15–30 W/m, length calculated against local minimum temperature and insulation thickness |
|---|---|
| Thermal management | Mechanical thermostat (10–30 °C adjustable) standard optional, controls heat tracing on/off |
| Steam heat tracing | DN15 steam tracing line + steam trap, designed to the site steam system |
| Temperature measurement | Thermometer mounting position inside the box (for inspection readings) |
| Power supply | Heat tracing circuit AC 220V, dedicated breaker and ground fault protection (supplied to drawing) |
| Explosion-proof note | For heat tracing and electrical accessories used in hazardous areas, supply scope is confirmed per project requirements |
| Pressure transmitter insulated box | One box per meter, impulse line heat-traced against freezing, general purpose for thermal networks |
|---|---|
| Multi-meter central box | 2–4 transmitters per box, mounting plates arranged in tiers |
| Flow meter head box | Local protection box for flow meter head, viewing window for readings |
| Steam tracing type | For plant areas with a steam system, tracing line + steam trap to drawing |
| Stainless steel corrosion-resistant type | For coastal and chemical areas, 304 + brushed finish, resists salt spray and corrosive atmospheres |
| Custom build | Non-standard dimensions, special connections, holes cut to piping drawings |
| Structural standard | GB/T 7251.1 / IEC 61439-1 (mechanical structure section) |
|---|---|
| Insulation calculation | Tracing power and insulation thickness calculated against local extreme minimum temperature and wind speed; calculation report included with delivery documents |
| Ingress protection check | Rain hood, double seal and drain ports visually inspected on every unit; seal compression marks continuous around the full perimeter |
| Heat tracing test | Insulation test on every electric tracing circuit + powered temperature-rise check (thermostat set point) |
| Documents with shipment | Outline drawing, tracing calculation report, hole and connection drawings |
Five steps to specify your run
A configuration summary is generated as you go. It travels with your inquiry, saving a round of confirmation.
Build details
Systems have been in service for decades, and the failure points are always the same few: poor busbar contact, water ingress at the door seal, high temperature rise in the correction cabinet, and mis-phased outgoing feeders. The six hard rules below are written for exactly these points — every cabinet can be traced to them.
Designed for the coldest day
Electric heat tracing length and wattage are calculated cabinet by cabinet based on the local extreme minimum temperature, wind speed and insulation thickness, and the calculation report ships with the order — guess at the heat tracing and your meters freeze during the coldest week.
Rain runs off the cabinet face
The top rain hood overhangs by ≥50 mm so rainwater drips off the edge instead of running along the door seam; a second seal on the door frame catches what gets past the first.
A path out for condensate
Drain holes in the cabinet floor give condensate inside the enclosure and moisture at the cable entry somewhere to go — standing water rusts through a cabinet floor long before low temperatures do.
Rock wool stays put
The insulating rock wool is faced with 0.5 mm galvanized steel so fibers do not shed onto meters and terminal blocks.
No hidden faults allowed in electric heat tracing
Every electric heat-tracing circuit gets an insulation test before power-up, followed by a temperature-rise check, with thermostat trip points recorded in the factory documentation — a shorted heat-tracing cable is the most insidious failure in an insulated enclosure.
Explosion-proof zones confirmed per project
For heat tracing and electrical accessories used in explosion-proof zones, the supply plan is confirmed to project requirements — we state the explosion-proof qualification scope honestly and do not make that call for the customer.
Photos & enclosure construction
Below are photos taken in our own shop — from the complete unit down to the internal busbars and secondary wiring. Every build detail can be checked item by item.
Image key: 01–05 are shop photos (the numbers match the shot list). The line drawing shows the front elevation of the enclosure; dimensions match the specification table above.
Where these cabinets go
These are the routine applications — we can talk scheme and configuration directly. For the industry view, see the industry pages.
Steam distribution networks
Winter freeze protection and insulation for pipeline pressure transmitters — electric or steam heat tracing.
Petrochemical plants
Field measurement point protection enclosures, 304 stainless for corrosive chemical areas.
Water treatment facilities
Rain and moisture protection for outdoor instruments — unheated or lightly heat-traced versions.
Natural gas stations
Instrument protection in pressure regulating and metering areas; heat tracing sized to local ambient temperatures.
Tank farm level measurement
Centralized protection for remote level and temperature transmitters in tank farms.
Brownfield revamps
Retrofit protection enclosures onto existing outdoor meters, with drawings produced from on-site measurements.
Commercial terms
Specification dated September 2026; quotations follow this.
| Drawings & design | Free |
| MOQ | 1 unit (5 or more recommended for production) |
| Production lead time | 15-25 days after drawing approval |
| on-time delivery | 98% |
| Warranty | 12 months |
| Loading port | Ningbo / Shanghai, China |
| Sheet steel | Baosteel / Ansteel cold-rolled sheet (SPCC) / 304 stainless steel |
| Factory visit & dispatch confirmation | Factory visits welcome; finished-cabinet photos and video before dispatch |
| Capacity | 5,800+ units / year |
Documents for your engineering team
Selection manual, outline dimensions and RFQ checklist — for the customer's electrical engineer. All three documents are being organized by product line; download links go live once complete.
Six questions procurement and electrical engineers ask most
How is heat tracing power determined?
Calculated enclosure by enclosure based on the local extreme minimum temperature, wind speed, enclosure dimensions and insulation thickness — not a one-size-fits-all wattage. Send us the project location and instrument list, and the calculation sheet comes with the quotation.
Electric or steam heat tracing — which one?
If the plant already has a steam system, use steam tracing (lower operating cost, but requires trap maintenance). If there is no steam or the measurement points are scattered, use self-regulating electric heat tracing (simple to install, self-controlling temperature).
Can it be used in explosion-proof zones?
For heat tracing and electrical accessories in explosion-proof zones, the supply plan is confirmed to project requirements — the explosion-proof qualification and nameplate scope must be clarified per project. We neither make blanket promises nor dodge the question.
How many instruments fit in one enclosure?
Standard is one to four instruments per enclosure, with layered mounting plates. When many instruments are grouped at one location, we build multi-instrument enclosures to the piping drawings — maintenance space matters more than packing them in.
Is stainless steel necessary?
For coastal areas, chemical plants and corrosive atmospheres, go straight to 304. For inland dry industrial areas, SPCC with an outdoor coating is sufficient — no need to spend more.
What about condensation on site in winter?
Drain holes at the bottom of the enclosure plus heat tracing to keep the internal temperature above the dew point — both together. An enclosure that only seals without draining will pool condensate at the bottom, which causes problems sooner than low temperatures do.
Other cabinet types in the same main circuit
Related products use color-block placeholders for now (product photos not yet complete; they will be replaced together). Internal links will be filled in once live URLs are confirmed.
Send the project climate data and instrument list — heat tracing calculated enclosure by enclosure
Send us the project location's minimum temperature and instrument list, and we will provide a free insulation and heat tracing plan with calculation sheet · reply within 24 hours. Direct from the source factory, MOQ 1 unit, 1-year warranty.
ISO 9001:2015 · CE(LVD+EMC) · CQC · IP65
When you write, include: single-line diagram or primary scheme, switch room layout, load list, and component brand requirements. You do not need complete drawings — capacity and cabinet type are enough to start.