Simbologia — Electrica Industrial Best

Here’s a solid, best-practice guide to industrial electrical symbology , focused on standards you’ll actually see on the job (IEC, NFPA, ANSI, and common machine builder variants).

1. Stick to the main standards

IEC 60617 (international – Europe, Asia, most modern plants) NFPA 79 / ANSI Y32.9 (North American industrial machinery) JIC (older US panels – still found in legacy systems)

✅ Best practice: On new designs, use IEC 60617 with a cross-reference table to ANSI for US clients. simbologia electrica industrial best

2. Core industrial symbols (must-know) Power & Supply | Component | IEC symbol | ANSI/NFPA symbol | |-----------|------------|------------------| | 3-phase supply (L1, L2, L3) | Three circles with L1/L2/L3 | Line with three slanted ticks | | Neutral (N) | Circle with N | Line with N | | Protective Earth (PE) | Vertical line, horizontal bottom line | Downward arrow + vertical line | | Chassis ground | Hollow triangle | Dashed line + horizontal line | Wires & Connections

Crossing wires (not connected) → no dot Connected wires → dot at junction Cable shield → dashed line around conductors + ground symbol at one end

Switches & Pushbuttons (industrial) | Device | Symbol note | |--------|--------------| | Normally open (NO) pushbutton | Two open circles, line connecting top to bottom when pressed | | Normally closed (NC) pushbutton | Same but with diagonal line through contacts | | Mushroom head emergency stop | Red NO symbol with large circle around actuator | | Selector switch (2-position) | Circle with line at 45° – shows position | | Limit switch (NO, spring return) | Triangle pushing on open contact | Contactors & Relays PNP) – symbol with +

Coil – rectangle (IEC) or circle (old ANSI) NO auxiliary contact – two parallel lines, open NC auxiliary contact – same but with diagonal slash Overload relay – rectangle with “OL” or thermal element symbol (curved line)

Motor control (most critical in industry) | Device | Symbol | |--------|--------| | 3-phase induction motor | Circle with M inside, three lines to terminals | | Single-phase motor | M with one line + capacitor symbol | | Motor starter (contactor + OL) | Contactor coil + OL in series below | | Reversing starter | Two contactors mechanically interlocked (dashed line between coils) | Sensors (proximity / photoelectric)

Inductive NO – rectangle with “I” and open contact Capacitive – rectangle with “C” Photoelectric (through-beam) – transmitter (LED symbol) and receiver (photo transistor) Proximity switch (3-wire, PNP) – symbol with +, load, output line Here’s a solid

3. Best-practice labeling (panel + drawing)

Function letters (IEC 81346):