What drives the price
A custom stainless steel ATEX enclosure is a fabricated product, not a catalogue item pulled from a shelf. The price reflects material cost, cutting and forming time, welding, finishing, hardware, and compliance testing. Each of the six factors below independently affects the final price, and most interact with each other.
The largest single driver, by a significant margin, is size. A doubling of all linear dimensions increases surface area by approximately four times and volume by eight times, and material cost, weld length, and handling time all track surface area, not volume. Small enclosures are relatively more expensive per square metre than large ones; large enclosures are cheaper per square metre but much more expensive in total.
1. Material grade
Most stainless steel ATEX enclosures are fabricated in 316L or 304 grade. The choice is driven by the installation environment:
| Grade | Composition difference | Key advantage | Price premium over 304 |
|---|---|---|---|
| 304 (1.4301) | 18% Cr, 8% Ni | Good general corrosion resistance; lower cost | Baseline |
| 316L (1.4404) | 16% Cr, 10% Ni, 2% Mo | Molybdenum addition resists chloride pitting; marine and coastal grade | 15–25% |
| 2205 Duplex | 22% Cr, 5% Ni, 3% Mo | Higher strength; excellent chloride resistance; lighter wall possible | 30–50% |
For offshore, coastal, and food processing applications, 316L is the standard. For general indoor or sheltered industrial use, 304 is adequate and more cost-effective. Duplex grades are rarely used for enclosures, the strength advantage is not typically needed, and the forming characteristics are less favourable for complex shapes.
2. Wall thickness
Standard wall thickness for ATEX stainless terminal boxes is typically 1.2 mm for small enclosures (up to approximately 600×600 mm) and 1.5 mm and 2mm for larger enclosures. Thickness affects:
- Material cost, directly proportional to weight; 2 mm sheet weighs 33% more than 1.5 mm
- Rigidity, thicker walls reduce deflection on large panel fronts and lids; important for maintaining lid-gasket contact and IP rating over the enclosure's life
- Weld quality and warpage, thinner material is more susceptible to heat distortion during welding; more skilled labour time is needed for thin-gauge work
For large floor-standing enclosures (1200×1000 mm and above), 2 mm walls are required for structural rigidity. The certificate will specify the minimum thickness, reducing wall thickness below the certified minimum invalidates the ATEX approval.
3. Overall size
Size is the dominant cost driver. Pricing scales approximately with surface area. A rough rule of thumb: doubling the footprint of an enclosure approximately doubles the price (because most of the cost is in the material and weld length, which track surface area).
4. Painting
Powder coating is the standard surface finish for mild steel enclosures and is available as an option for stainless steel. Adding a powder coat finish adds cost and at least one week to the lead time, as the enclosure is sent to a finishing facility and must be returned before dispatch.
Stainless steel enclosures are supplied in a No.4 brushed finish as standard, which is suitable for most industrial and outdoor applications without further treatment.
5. Lead time
Lead time affects price in two ways. First, rush orders on tight schedules require premium scheduling, other work is displaced, overtime may be required, and the planning margin is reduced. Rush premiums of 15–30% are common for lead times below 2 weeks.
Standard lead times from UK manufacturers of enclosures can be up to 16 weeks. However indEx Enclosures ships its custom enclosures within 3–4 weeks. Cabinets, control panels and painted mild steel enclosures are shipped within 4–6 weeks.
6. Certification and compliance
ATEX certification is included in the base price for enclosures designed and certified within indEx Enclosures' existing certificate scope. If a custom design requires modifications that fall outside the existing certificate, a supplementary examination by the Notified Body adds cost and lead time (typically 4–8 weeks and several hundred to a few thousand pounds, depending on scope).
Indicative price ranges
The following ranges are indicative for 316L stainless steel, No.4 brushed finish, ATEX certified to Ex eb IIC T6 Gb, IP66, with standard entries:
| Enclosure size | Indicative price range (single unit) | Notes |
|---|---|---|
| 100×100×80 mm | £150 – £280 | Standard size |
| 200×200×150 mm | £280 – £450 | Very common size |
| 300×250×150 mm | £400 – £650 | Standard range |
| 400×300×200 mm | £550 – £900 | Custom entry configurations add cost |
| 600×500×250 mm | £900 – £1,500 | Larger welded assembly |
| 800×600×300 mm | £1,400 – £2,200 | Hinged lid, multiple locks typical |
| 1200×1000×300 mm (cabinet) | £3,000 – £6,000+ | Complex fabrication; internal fitting extra |
These ranges are single-unit prices. Volume discounts are available on repeat orders and project quantities, typically 10–20% for five or more identical units, and 20–30% for larger project quantities.
For an indicative price, use the online configurator or contact the engineering desk with your specification, dimensions, entry configuration, IP rating, and certification requirements.
See also: How to choose the right ATEX enclosure · UK ATEX enclosure manufacturers compared