OPERATION
Under normal operating conditions, a low impedance is present between the –IN and –OUT terminals of the base, so that power and signals pass to the next base in line.
If a short-circuit or abnormally low impedance occurs, the fall in voltage is sensed and the base isolates the negative supply in the direction of the fault. The isolated section is tested using a current pulse every five seconds. When the short-circuit is removed, the power will automatically be restored.
From this the isolator will isolate on whatever side the short is on so it will be from the out on one and on the in on the other (or vice versa) so I don't think (well,Ive never checked it myself up to now) it matters but Id run it past Apollo just in case.