a protective relay for producing {TAIL ~ a breaker opening command} when a fault occurs on {HEAD ~ a load side} of the breaker 
a protective relay for producing { TAIL ~ a breaker opening command } when a fault occurs on { HEAD ~ a load side } of the breaker
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH