Your electric grass trimmer my be defective in:
Socket you plug it into (try a known good socket)
Fuse in plug (if fused plug) (continuity test fuse)
Integrity of power cable (especially close to appliance where trim line may have severed conductor) (inspect closely with cord unplugged)
Control switch (dismantle trimmer to continuity test)
Internal cable (very rare and unlikely)
Motor (dismantle trimmer and run on bench if confident)
TAKE CARE
Twisting cord for "short"
Unless a fuse/breaker has blown/tripped then there will have not been a short - any cable problem is 90% likely to be an open circuit rather than a short circuit.
When continuity testing a cable you should test both supply & return wires.
Peccavi
September 2009