AbbreviationDescriptionSymbolIEC
SPSTSingle pole, single throw
SPDTSingle pole, double throw
SPCOSingle pole changeover or Single pole, centre off
SPTTSingle Pole, Triple Throw
DPSTDouble pole, single throw
DPDTDouble pole, double throw
DPCODouble pole changeover or Double pole, centre off
Intermediate switchDPDT switch internally wired for polarity-reversal applications