Explosion-Proof Push Button Switches
Control stations, push buttons, selector switches and pilot lights for local control in hazardous areas.
Typical range
- Control station with 1–8 push buttons
- Emergency stop push button with lock-off
- Selector and key-operated switches
- Pilot light and indicator units
Indicative specification
- Protection: Ex d IIC T6 / Ex e
- Ingress protection: IP66
- Rated voltage: AC 220 / 380 V, DC 24 V
- Contacts: 1NO+1NC up to multi-contact assemblies
- Ambient: -40 to +55 °C
Applications
Local control of motors, valves and pumps; emergency stop circuits; control panels and field stations.
Part of the explosion-proof electrical apparatus range. Request a quote with your contact configuration.
How a control station is specified
A push button in a hazardous area is a small item with a long specification, because the function, the contact arrangement and the enclosure all have to agree before the station is built. These are the points that decide the drawing:
- Function. Start, stop, open, close, reset, test — say what the operator has to do, not just “a button”.
- Contact arrangement. 1NO+1NC is the common starting point; multi-contact assemblies are used when one operation has to signal several circuits at once.
- Voltage. AC 220 / 380 V and DC 24 V control circuits are all in the range; state which one the panel uses.
- Protection concept. Ex d IIC T6 enclosures where the device makes and breaks a circuit; Ex e where the station only terminates and indicates.
- Station size. Control stations are built with 1 to 8 operators, so the enclosure is sized by the legend, not by the button.
- Mounting and marking. Local field station or panel section, and the zone / group of the area it sits in.
What the different operators are for
| Unit | What it does | Normally specified when |
|---|---|---|
| Push button | Momentary contact while held | Start, jog and reset functions, and any operation that must not latch |
| Selector switch | Positions that stay where they are set | Local / remote and auto / manual selection |
| Key-operated switch | A position that only authorised staff can change | Where a mode change must be restricted, for example maintenance or test modes |
| Pilot light | Indication only, no switching | Run, trip and supply-healthy indication at the local station |
| Emergency stop | Latching stop with a lock-off provision | Any machine that has to be stopped locally and kept stopped during intervention |
Legends, marking and site consistency
Most control-station problems on site are not electrical. They are legends that do not match the panel drawing, or two stations in the same plant that look identical but do different things. Ordering stations with engraved legends from the start, and keeping one enclosure family across the site, is cheaper than re-labelling after commissioning — and it matters more in classified areas, because every change to the enclosure has to be made in a way that keeps the certification valid.
Frequently asked questions
Can a pilot light be added to an existing station?
Only if the enclosure was built with the position for it. Adding an operator means machining the front plate in the way the certification allows, so it is normally cheaper to order the station with the full complement of operators.
Why are emergency stop contacts normally closed?
So that a damaged cable or a loose terminal causes a stop instead of leaving the machine able to run. This is a circuit-design principle, not a property of the button.
Is Ex d needed for a control station in Zone 2?
Zone 2 allows Ex e or non-sparking solutions where the area classification permits them, but stations that switch circuits are usually ordered in Ex d so that one design can be used across the plant.
Can you engrave the legend we need?
Yes. Send the legend text with the order — including any language requirement — and it is engraved as part of the build.
What about the cable entries?
Entries are specified with the station: count, thread standard and face. Unused ways must be closed with certified stopping plugs.
What to send us for a quote
- Function list and contact arrangement for each operator
- Control voltage and, if relevant, the signal voltage
- Number of operators per station and the legend text
- Zone / gas group and mounting arrangement
- Cable entry count, thread standard and quantity
Request a quote with the contact configuration and we will confirm the closest station.
Control-station and push-button assembly, including internal wiring and contact blocks, is shown in our factory videos.
Explosion-Proof Push Button Switches: Frequently Asked Questions
Configuring control stations for hazardous areas, from single buttons to full emergency-stop assemblies.
What can be built into an explosion-proof control station?
Pilot lights, momentary and maintained push buttons, selector and key-operated switches, ammeters and voltmeters, and emergency-stop actuators. Stations are supplied with one to six positions, as a single local control point or as a grouped panel, and they can be delivered pre-wired to a terminal block so field installation only needs the incoming supply and the outgoing control cores.
Which protection concept do your push buttons use?
The standard range uses increased safety Ex e enclosures with Ex d or Ex de contact blocks, which is the usual choice for Zone 1 and Zone 2 power and control circuits. For instrumentation and intrinsically safe loops we supply Ex ib versions for use with Ex i barriers, where the energy in the circuit itself is limited so that no ignition-capable spark can occur.
What should an emergency-stop station satisfy?
The actuator should be a mushroom head that latches when pressed and needs a deliberate release action, in line with ISO 13850 and EN 60947-5-5, and the station should be reachable without passing through the hazard. Because an emergency stop is a safety function, the wiring between station and contactor or drive should be reviewed with your safety architecture rather than treated as ordinary control wiring.
Can one push button switch several circuits?
Yes, contact blocks can be stacked in different combinations, for example one normally closed contact for the control circuit and one normally closed contact for a monitoring or signalling circuit. Tell us how many contacts and of which type you need for each position, and the number and size of the cable entries, and we will assemble the station accordingly.
Question not answered here? Send it to our engineering team — we answer hazardous-area selection questions with the relevant standard referenced.
Related: explosion-proof electrical apparatus, junction boxes, plugs and sockets.
