30 Essential Electrical Letter Symbols

Live wire — L

Neutral — N

Protective earth — PE

Alternating current — AC

Direct current — DC

Normally open — NO

Normally closed — NC

Push button switch — SB

Selector (rotary) switch — SA

Isolator switch — QS

AC contactor — KM

Intermediate relay — KA

Thermal overload relay — FR

Fuse — FU

Circuit breaker — QF

Forward — FWD

Reverse — REV

Positive — VCC

Ground — GND

Motor — M

Start — ST

Stop — STP

Run — RUN

Close — ON

Open — OFF

Transmit — TX

Receive — RX

Input — IN

Output — OUT

Generator — G