Foot Switch Symbol
Definition: The Foot Switch symbol represents a foot-operated pilot device that opens or closes contacts when the operator presses a pedal, drawn per NEMA ICS / IEC 60947-5-1 conventions as a contact symbol with a wedge-shaped pedal actuator, here with Common and NO (normally open) terminals.
Also known as: foot pedal switch, treadle switch, pedal switch, foot-operated switch, footswitch, guarded foot switch, momentary pedal.
What the Foot Switch symbol means
The Foot Switch symbol denotes a control-circuit (pilot-duty) switch actuated by the operator's foot, freeing both hands for workpiece handling. Like a push button it is a command device, not a power switch: in a typical diagram its NO contact closes a relay or contactor coil circuit, a solenoid valve, or a PLC input rather than carrying motor current directly. The 'normally open' state is defined with the pedal released — pressing the pedal closes Common to NO; releasing it re-opens the circuit (momentary action), unless the switch is a maintained (latching) type.
Because foot switches often initiate hazardous machine motion (press strokes, welder fire, shear cuts), diagrams frequently show them wired in series with guards, anti-tie-down logic, or two-hand controls. Safety-rated foot switches add a third 'kick-out' position or dual redundant contacts monitored by a safety relay, and machine-safety standards restrict when a foot switch alone may initiate a press stroke.
How to identify the Foot Switch symbol
The distinguishing feature is the actuator: a wedge or pedal shape drawn above (or attached by a lever to) an otherwise standard contact symbol. In NEMA/ANSI ladder diagrams the foot switch appears as the familiar NO or NC contact drawn with a curved treadle mark — JIC/NEMA symbol charts list it explicitly as 'foot switch, normally open' and 'foot switch, normally closed'. In IEC 60617 the same idea is expressed with the general contact symbol plus the foot-operated actuator qualifier (a pedal-shaped operator linked to the contact by a mechanical dashed line).
Do not confuse it with a limit switch (roller or lever actuator) or a pressure switch (diaphragm qualifier): the pedal/treadle mark is what says 'operated by foot'. NO contacts are drawn open-circuit; NC contacts closed — always in the released (unactuated) state.
Function in a circuit
Mechanically, pressing the pedal drives a plunger or lever that snaps an internal contact block — usually the same double-break contact blocks used in push-button stations — from its resting state to its actuated state. Momentary versions return by spring when the foot lifts; maintained versions alternate state on successive presses, like a push-on/push-off button. Industrial pedals are commonly housed in cast-metal enclosures with a full guard hood so a falling object cannot actuate them accidentally (anti-trip protection).
In the control circuit, the NO contact typically energizes a contactor coil, solenoid valve, or PLC input for as long as the pedal is held — giving the operator dead-man style control of jog, feed, or weld functions. Safety-function pedals use two contact channels plus a distinct third pedal position (full overtravel opens the circuit again) so that a startled operator stamping down hard stops the machine rather than continuing the stroke.
Standards: IEC vs ANSI
| IEC 60617 | IEC 60947-5-1 (Low-voltage switchgear — Control circuit devices and switching elements) governs the contact ratings and utilization categories (AC-15, DC-13) of foot switches; IEC 60617 provides the contact symbol with a foot-operated actuator qualifier. Machine-application rules come from ISO 12100 risk assessment and type-C standards for presses. |
|---|---|
| ANSI/IEEE 315 | NEMA ICS 5 covers control-circuit pilot devices in North America; the JIC/NEMA symbol set includes dedicated foot switch NO and NC symbols (contact with treadle mark). NFPA 79 governs their use in industrial machinery control circuits; ANSI B11 machine-tool standards restrict foot-switch initiation of hazardous strokes. |
| Key difference | NEMA/JIC diagrams use a specific pictorial treadle mark on the contact; IEC 60617 builds the symbol from a general contact plus a foot-actuator qualifier linked by a dashed mechanical line. Contact behaviour conventions are identical: state is drawn as-released, and ratings are expressed as NEMA designations (e.g. A600) or IEC utilization categories (e.g. AC-15). |
Terminals / pins
| Pin | Name |
|---|---|
| com | Common |
| no | NO |
Typical values
Typical industrial foot switches carry pilot-duty ratings such as NEMA A600 / IEC AC-15: about 10 A continuous thermal current, switching 120–600 V AC control circuits (e.g. 6 A at 120 V AC, 3 A at 240 V AC inductive), and DC-13 ratings near 0.5–1 A at 125 V DC. Contact blocks are usually 1NO+1NC or 2NO+2NC, snap-action, double-break. Mechanical life runs 1–10 million operations; enclosures are commonly IP65–IP67 cast aluminium with guard hoods. Safety-rated models offer two-channel contacts suitable for Category 3 / PL d or e circuits per ISO 13849-1.
Where the Foot Switch symbol is used
- Spot and MIG welding stations where the operator holds the workpiece with both hands and fires the weld by pedal
- Hydraulic and mechanical press controls (with guarding and anti-tie-down logic per ANSI B11 / press safety standards)
- Industrial sewing machines and textile equipment controlling motor run and speed
- Sheet-metal shears, brakes, and tube benders initiating the cutting or bending stroke
- Medical and laboratory equipment (dental drills, surgical tools) where sterile hands-free control is required
- Conveyor jog and hoist inch controls giving dead-man style momentary motion
Example
In a spot-welder control diagram, the Foot Switch symbol's Common pin connects to the 120 V AC control-circuit hot leg and its NO pin feeds the weld-initiate relay coil: pressing the pedal closes Common to NO, energizing the relay for the duration of the press, which in turn triggers the weld timer. The contact is rated A600 pilot duty (6 A at 120 V AC inductive), and the pedal is a guarded, momentary type so the weld cannot fire from a dropped object.
Key facts
- A foot switch is a pilot device: it switches control circuits (coils, solenoids, PLC inputs), not motor power — the same contact blocks as push-button stations, actuated by pedal instead of finger.
- Contact state on the symbol is always drawn with the pedal released: NO = open until pressed, NC = closed until pressed.
- Momentary (spring-return) action is standard; maintained (alternate-action) versions latch on each press.
- Guard hoods (full-shield enclosures) provide anti-trip protection so falling objects cannot actuate the pedal — mandatory in many press applications.
- Ratings follow NEMA designations (e.g. A600) or IEC 60947-5-1 utilization categories (AC-15 for AC coils, DC-13 for DC coils).
- Safety-rated foot switches provide dual redundant contact channels and a three-position action (mid-travel = run, full stamp-down = stop) for ISO 13849-1 Category 3 circuits.
- Machine-safety standards (ANSI B11 series, press type-C standards) restrict using a foot switch alone to initiate a hazardous stroke — guards or two-hand control usually accompany it.
- Typical electrical life is 100,000–1,000,000 operations at rated pilot duty; mechanical life up to 10 million.
Frequently asked questions
What does the foot switch symbol look like in a ladder diagram?
It is a standard NO or NC contact drawn with a pedal/treadle mark — a small wedge or curved foot lever — attached to the contact. JIC/NEMA symbol charts list 'foot switch NO' and 'foot switch NC' explicitly; IEC 60617 shows a general contact linked by a dashed mechanical line to a foot-operator qualifier. The contact state shown is always with the pedal released.
Is a foot switch normally open or normally closed?
Both exist, and many pedals contain one of each (1NO+1NC). 'Normally' refers to the released state: an NO foot switch closes its circuit only while pressed (typical for initiate/run functions), while an NC contact opens when pressed (used for interlocks or, in safety pedals, the stop channel). This symbol provides Common and NO terminals — the most common start/run configuration.
Can a foot switch start a machine on its own?
Only if the risk assessment allows it. Machine-safety standards (ANSI B11 series, ISO 12100-based type-C standards) generally prohibit a bare foot switch from initiating a hazardous stroke unless the point of operation is guarded, or the pedal is a safety-rated three-position type monitored by a safety relay with anti-tie-down and single-stroke logic. For non-hazardous functions (welder fire with proper fixturing, conveyor jog) a standard momentary pedal is normal practice.
What is a three-position safety foot switch?
A pedal with three detectable positions: released (off), mid-travel (enable/run), and full depression past a tactile break point (off again, often latching until manually reset). The idea is that a startled operator either releasing or stamping down hard both result in a stop. Combined with dual redundant contacts monitored by a safety relay, it supports Category 3 / PL d-e circuits per ISO 13849-1.
What current can a foot switch handle?
Standard industrial pedals are pilot-duty devices: NEMA A600 or IEC AC-15 rated around 10 A thermal, switching roughly 6 A at 120 V AC or 3 A at 240 V AC inductive, and about 0.5–1 A at 125 V DC (DC-13). They are meant to drive contactor coils, relays, solenoid valves, or PLC inputs — not to carry motor load current. For direct motor switching, use the pedal to drive a contactor.
Related symbols
- Emergency Stop symbol
- Limit Switch NC symbol
- Limit Switch NO symbol
- Push Button NC symbol
- Push Button NO symbol
- Relay Coil symbol
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