3.2.2.3 Relay symbols

General relays symbol names shall be RL A B C D E F where:

  • A = Generic name (see below) or manufacturer e.g. TYCO
  • B = Generic build (see below) or family e.g. IM, HF
  • C = optional configuration for variations
  • D = optional additional information such as TH or SM for variations
  • E = D optional diode
  • F = optional SPLIT if a split relay model


Generic name

  • 1A = SPST (NO)
  • 1B = SPST (NC)
  • 2A = DPST (NO)
  • 2B = DPST (NC)
  • 1A1B = DPST (NO & NC)
  • 1C = SPDT
  • 2C = DPDT


Generic build DPDT abcdefgh<space>i(j etc)

  • a = +coil pin number
  • b = -coil pin number
  • c = NO 1 pin number
  • d = COM 1 pin number
  • e = NC 1 pin number
  • f = NO 2 pin number
  • g = COM 2 pin number
  • h = NC 2 pin number
  • i = GND or Screen pin number(s)