A selector switch, a pushbutton, and a [pilot light](/encyclopedia/pilot-light.html) are three distinct control-device families that routinely share the same panel cut-out and the same 22 mm or 30.5 mm mounting hole, which is exactly why specifying engineers confuse their roles on first-pass panel layouts [S4]. The three families differ in their electrical contact logic (maintained vs momentary), in their visible front-of-panel state (a switch position, a button cap, or an illuminated dome), and in their compliance scope (general industrial IP65 vs ATEX/IECEx for hazardous areas) [S1][S2].
Current IDEC, Werner Electric, Eaton, and OMEGA pilot-device catalogues all group these three products under the same "30 mm pilot devices" or "22.5 mm command & signalling" umbrella, with shared accessories such as contact blocks, transformer blocks, and legend plates, but with different operator heads, different contact configurations, and different electrical ratings per operator type [S3][S4]. This article lays out the spec bands, the standards, and the selection logic a process or panel engineer needs to pick the right device for each control function.
Definition and Functional Scope of the Three Device Families
Per IDEC and OMEGA pilot-device documentation, a selector switch is a manually operated control switch with two or more maintained positions (typically 2-, 3-, or 4-position) whose knob or lever stays in the position the operator last moved it to, driving a different contact combination at each detent [S4]. A pushbutton, by contrast, is a momentary operator: spring-return on the standard version, with a contact block that closes (N/O) or opens (N/C) only while the operator is actively pressing the cap, and returns to its normal state when the operator releases [S3].
A [pilot light](/encyclopedia/pilot-light.html) is not a switching device at all: it is an indicating light with a single lamp block (typically LED, 24 V AC/DC, 120 V AC, or 240 V AC variants) and no electrical contacts, used purely to show the state of a process or machine [S2][S4]. IDEC and Werner lines list illuminated selector switches and illuminated pushbuttons as separate SKUs, but the illumination is added by inserting an LED lamp block into a selector or pushbutton operator — the underlying switching function is unchanged [S1][S2].
Mounting Standards, Cut-Out Sizes, and IP Ratings Across the Three Families
OMEGA's E34 series and equivalent Eaton M22 / Cutler-Hammer 10250T lines all use the 30.5 mm (1-13/64 in) round panel cut-out as the North American default for heavy-industry pilot devices, while IDEC's HW and EU2B series and Werner's 40 series use the 22.5 mm metric cut-out as the IEC default [S3][S4]. Both cut-out sizes are documented as compatible with the same contact-block depth (roughly 50-60 mm behind the panel) and the same finger-safe terminal screws, so the choice between 22 mm and 30 mm is mechanical and aesthetic, not electrical [S1][S4].
Ingress protection differs sharply across the three families within the same series: Werner's 40-series selector switch is rated IP65 at the front-of-panel (dust-tight, jet-proof) for the standard knob, with an IP40 option for the compact body, and the matching pushbutton and pilot light in the same Werner line inherit the same IP65 front rating [S2]. For hazardous-area applications, IDEC's EU2B series extends the standard 22 mm operator to ATEX-certified emergency-stop, key-lock, and selector versions with the certification printed on the nameplate — the IP65 front rating is preserved, and the ATEX marking covers the operator-and-contact-block assembly as a unit, not the operator head alone [S1].
Contact Logic, Electrical Ratings, and Operator Types
Selector switches ship in maintained (latching) form as the catalogue default, with spring-return-from-left and spring-return-from-right variants available for momentary operations, and contact blocks typically rated 600 V AC / 10 A continuous (UL/CSA) or 250 V / 5 A (IEC) depending on the series [S2][S4]. A 2-position maintained selector wired with one N/O + one N/C contact block gives a binary "Run/Stop" or "On/Off" logic; a 3-position maintained selector with two N/O contact blocks gives the classic "Hand/Off/Auto" (HOA) logic used on motor starters and pump control panels [S4].
Pushbuttons ship in two electrical modes: momentary (spring-return, the default) and maintained (push-on/push-off, a separate SKU with a latching mechanism inside the operator body). Contact blocks are interchangeable between pushbutton and selector operators within a given series, which is why IDEC, Eaton, and OMEGA all sell "contact blocks" and "lamp blocks" as separate line items from the operator heads [S3][S4]. Pilot lights carry no electrical contacts — they only accept a single lamp block (LED 6 V, 12 V, 24 V, 120 V, 240 V, or a universal 24 V AC/DC variant) and the front lens colour (red, green, amber, blue, white) is a separate orderable part [S2].
Illuminated Operators and the Shared Lamp-Block Architecture
Werner's 40-series and Reny Electric's parallel line both market "LED-illuminated selector switches" and "illuminated push buttons" as standard catalogue SKUs, with green, red, white, and blue LED colours listed in the product characteristics [S2][S5]. The illumination is added by inserting a full-voltage or transformer-type LED lamp block into the centre of a selector or pushbutton operator — the same lamp block that would otherwise drive a standalone pilot light [S2][S4].
This shared lamp-block architecture is the technical reason a panel builder can specify one LED voltage (typically 24 V AC/DC for control panels fed from a 24 VDC PSU, or 120 V AC for North American motor-control centres) and use it across all three device families on the same panel, cutting the lamp-block SKU count by roughly two-thirds [S2][S4]. The trade-off is that a faulty LED lamp block takes down the indication on every device it is installed in, so spares policy and lamp-life ratings (typically 50,000-100,000 hours for industrial LED blocks) become a panel-engineering decision, not just a purchasing one [S2].
Hazardous-Area Compliance: When a Selector or Pushbutton Steps Outside IP65
IDEC's EU2B series carries an ATEX marking on the operator nameplate, covering emergency-stop, key-lock, and selector variants in the same 22 mm body [S1]. This is the only path the three device families have into Zone 1 / Zone 2 (gas) or Zone 21 / Zone 22 (dust) hazardous areas, and it requires the matching ATEX-certified contact blocks and lamp blocks to be fitted at the factory — field-substitution of non-ATEX contact blocks into an ATEX operator voids the marking [S1].
For a panel inside a non-hazardous industrial area, a standard IP65 selector, pushbutton, or [pilot light](/encyclopedia/pilot-light.html) from the Werner 40 series, the Eaton M22 line, or the OMEGA E34 line is the default specification, and the emergency light or explosion-proof light categories do not apply to the panel itself [S2][S3][S4]. A useful companion read is the pushbutton and pilot light vs emergency stop button spec-band breakdown, which lays out the contact-logic and colour-coding differences between a normal-state pushbutton and a certified E-stop mushroom-head in the same 22 mm and 30.5 mm form factors.
Criteria-Based Comparison: Selector vs Pushbutton vs Pilot Light
On four decision criteria the three device families line up as follows, per the IDEC, Werner, Eaton, and OMEGA product data [S1][S2][S3][S4]: (1) Output type — selector gives maintained multi-position switching, pushbutton gives momentary switching, pilot light gives no switching output (indication only). (2) Operator state visible on the panel — selector shows the knob/lever position, pushbutton shows the cap height (flush, extended, mushroom), pilot light shows the lens colour and on/off state. (3) Typical electrical rating per contact — 600 V AC / 10 A (UL) or 250 V / 5 A (IEC) for the switching families, no contact rating for the pilot light. (4) Lamp-block compatibility — pilot light always carries a lamp block, selector and pushbutton carry a lamp block only on the "illuminated" SKU variant.
Engineers should pick a selector when the panel needs a maintained mode change (HOA, Local/Remote, Manual/Auto), a pushbutton when the panel needs a momentary command (Start, Stop, Reset, Jog), and a pilot light when the panel needs remote indication of a process state (Run, Fault, Power On) without any switching action [S1][S2][S4]. Mixing the three in a single 22 mm or 30.5 mm cut-out is the standard pattern, with the shared contact-block and lamp-block architecture keeping the BOM and the spare-parts list compact [S1][S2][S3][S4].
Sourcing, Standards, and Trackable 2026 Signals
Standards governing the three device families include IEC 60947-5-1 (low-voltage switchgear, control-circuit devices, electromechanical control switches including pushbuttons and selector switches), IEC 60947-5-5 (control-circuit devices — emergency-stop devices with mechanical latching function), and the ATEX 2014/34/EU directive plus the IEC 60079 series for hazardous-area variants of the same 22 mm and 30.5 mm operator families [S1][S4]. The Werner 40 series, IDEC HW/EU2B, Eaton M22, and OMEGA E34 are all third-party-certified to these standards, with the certification marking printed on the product nameplate or referenced in the catalogue [S1][S2][S3][S4].
Two trackable signals for 2026 panel-engineering sourcing: (1) Reny Electric and other Asian OEM lines now publish a combined "illuminated pushbutton / illuminated selector / pilot light" family under one catalogue number series, which is a useful shorthand for buyers consolidating SKUs across all three functions [S5]. (2) The Cutler-Hammer / Eaton 10250T-style 30.5 mm legacy SKUs and IDEC / Werner's 22 mm metric SKUs both remain in active distribution on the surplus market alongside the current production lines, which is relevant for spare-parts continuity on panels older than roughly 2010 [S6].