EX Stainless steel terminal box
Construction and materials
HARDO HTB1S is an explosion-proof terminal box manufactured in stainless steel AISI 316L (the most corrosion-resistant of the commonly used steel grades for industrial applications) and certified for use in explosive atmospheres in accordance with the ATEX Directive (2014/34/EU) and the IECEx standard. The terminal box is approved for Zone 1, 2, 21 and 22 and is suited for demanding industrial environments, including offshore, chemical and pharmaceutical industries as well as process plants and refineries where corrosion resistance is critical.
The enclosure and lid are manufactured from 1.5 mm stainless steel AISI 316L. The enclosure can house Ex e and Ex i terminal rails and can be supplied with a hinged lid, internal mounting plate and cable gland plates. The HTB1S is part of HARDO's comprehensive series of increased safety enclosures, which are also available in GRP and copper-free aluminium.
Applications
The HTB1S series is used for terminal boxes, control stations, instrument housings, isolators and switches, battery containers, emergency call units, circuit breakers, lighting controls and electrical housings for use in hazardous areas. The terminal box can house terminal rails for conductors with a maximum cross-section of 16 mm², including terminal rails for intrinsically safe circuits. The enclosure is suitable for both indoor and outdoor installation and is used in offshore, onshore, chemical and pharmaceutical production facilities.
Customisation and configuration
The HTB1S is available in 24 standard sizes from 100×120×100 mm to 1250×800×400 mm and can be further customised within the limits of the certification up to 910×1140×500 mm for special configurations. The enclosure can be supplied with a hinged lid, mounting plate and cable gland plates for use with Ex cable glands for armoured cable or unarmoured cable. The maximum number of terminal rails depends on the terminal rail cross-section, current, enclosure size, operating temperature and required temperature class. HARDO's technical department supports the design of the right solution. Contact Particulair with your requirements and we will coordinate a solution directly with the manufacturer.
Catalogues and data sheets
- HARDO Product Brochure – Electrical Equipment for Hazardous Areas
Overview of HARDO's complete range of terminal boxes, control stations and electrical equipment for ATEX and IECEx zones, July 2025. - HARDO Company Brochure
Introduction to HARDO by Grupa WOLFF, product programme and certification overview. - Use and Maintenance Instruction – HTB1S / HCS1 Series. TN2111
Technical installation and maintenance guide for HTB1S terminal boxes and HCS1 control stations from HARDO.
Related technical knowledge
- ATEX ABC. Before there are sparks, there are choices
Understanding the ATEX regulations and what they mean for equipment selection at your facility. - How to read Ex markings – guide from HARDO
Practical guide to understanding ATEX and IECEx markings on explosion-proof equipment.
FAQ
Which zones is the HTB1S approved for?
The HTB1S is approved for Zone 1 and 2 (gas) and Zone 21 and 22 (dust) in accordance with the ATEX Directive and the IECEx standard.
What is the IP rating of the HTB1S?
The HTB1S has an enclosure protection rating of IP66, meaning the enclosure is completely dust-tight and protected against powerful water jets. This makes it suitable for both indoor and outdoor installation in demanding environments.
Can the HTB1S be used outdoors?
Yes. The HTB1S is certified for both indoor and outdoor installation. The ambient temperature can range from -50°C to +95°C depending on the model and configuration, making the enclosure suitable for installation in arctic environments as well as hot industrial plants.
Why choose stainless steel over aluminium or GRP?
Stainless steel AISI 316L offers the highest corrosion resistance of all common materials and is particularly well suited for offshore, chemical and pharmaceutical industries as well as environments subject to seawater corrosion. GRP and aluminium may be relevant choices in other environments. Contact Particulair for guidance on the right material for your project.
Can the enclosure be customised?
Yes. The HTB1S is available in 24 standard sizes from 100×120×100 mm to 1250×800×400 mm. Dimensions can be further customised within the limits of the certification up to 910×1140×500 mm for special configurations. The enclosure can be supplied with a hinged lid, mounting plate and cable gland plates. Contact Particulair with your specifications and we will find the right solution.
What information do I need to provide to receive a quotation?
To enable us to provide you with an accurate quotation quickly, it is helpful to know the enclosure size or internal dimensions, zone classification (Zone 1, 2, 21 or 22), number of units and any requirements for cable entries and mounting plates. Contact Particulair and we will help specify the right configuration directly with HARDO.
What accessories can be used with the HTB1S?
The HTB1S can be fitted with Ex cable glands for armoured cable and unarmoured cable for safe cable entry. The enclosure is also available with a hinged lid, mounting plates and cable gland plates. Contact Particulair for advice on the right combination for your installation.
How do I place an order?
The HTB1S is supplied on a quotation basis. Contact Particulair with your specifications and we will help identify the right size and configuration.
Technical documentation
Technical data
| Certification | ATEX, IECEx |
| ATEX marking | II 2 G Ex db eb ia/ib mb IIC/IIB T6…T4 Gb II 2 D Ex tb IIIC T85°C…T135°C Db |
| IECEx marking | Ex db eb ia/ib mb IIC/IIB T6…T4 Gb Ex tb IIIC T85°C…T135°C |
| Zones | Zone 1, 2 (gas), Zone 21, 22 (dust) |
| Material | Stainless steel AISI 316L, 1.5 mm wall thickness |
| Ambient temperature | -50°C to +60°C (ATEX and IECEx standard) Up to +95°C for HT models |
| Enclosure rating | IP66 |
| Rated voltage | Max. 1000 V |
| Rated current | Max. 160 A |
| Size range | 24 standard sizes, 100×120×100 mm to 1250×800×400 mm |
Dimensions
A = external width, B = external height, C = external depth, D = width incl. mounting flanges, E = height incl. mounting flanges. All dimensions in mm.
| Type | A | B | C | D | E |
|---|---|---|---|---|---|
| HTB1S101210 | 100 | 120 | 100 | 150 | – |
| HTB1S142013 | 140 | 200 | 130 | 170 | – |
| HTB1S151510 | 150 | 150 | 100 | 180 | – |
| HTB1S202016 | 200 | 200 | 160 | 230 | 160 |
| HTB1S202713 | 200 | 270 | 130 | 230 | 230 |
| HTB1S272713 | 270 | 270 | 130 | 300 | 230 |
| HTB1S203016 | 200 | 300 | 160 | 230 | 260 |
| HTB1S273513 | 270 | 350 | 130 | 300 | 310 |
| HTB1S282816 | 280 | 280 | 160 | 310 | 240 |
| HTB1S204016 | 200 | 400 | 160 | 230 | 360 |
| HTB1S353516 | 350 | 350 | 160 | 380 | 310 |
| HTB1S282827 | 280 | 280 | 270 | 310 | 240 |
| HTB1S355016 | 350 | 500 | 160 | 380 | 460 |
| HTB1S383816 | 380 | 380 | 160 | 410 | 340 |
| HTB1S384516 | 380 | 450 | 160 | 410 | 410 |
| HTB1S385716 | 380 | 570 | 160 | 410 | 530 |
| HTB1S505016 | 500 | 500 | 160 | 530 | 460 |
| HTB1S383827 | 380 | 380 | 270 | 410 | 340 |
| HTB1S575716 | 570 | 570 | 160 | 600 | 530 |
| HTB1S577620 | 570 | 760 | 200 | 600 | 720 |
| HTB1S575730 | 570 | 570 | 300 | 600 | 530 |
| HTB1S769520 | 760 | 950 | 200 | 790 | 910 |
| HTB1S202716 | 200 | 270 | 160 | 230 | 230 |
| HTB1S1258040 | 1250 | 800 | 400 | 1280 | 360 |
A = external width, B = external height, C = external depth, D = width incl. mounting flanges, E = height incl. mounting flanges. All dimensions in mm.
