The switching apparatus includes one or more sensing devices for detecting {HEAD ~ the condition} of {TAIL ~ the system}, directly or indirectly 
of
The switching apparatus includes one or more sensing devices for detecting { HEAD ~ the condition } of { TAIL ~ the system } , directly or indirectly
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH