The requirement of 760.10 seems pretty straight forward: label all PLFA circuits where they terminate or are installed in junction boxes. But one fire alarm contractor is telling me that its only required where it might cause confusion for other trades such as at a duct detector on a large air handler. Using the line from the NEC, "in a manner that will prevent unintentional interference with the fire alarm circuits during testing and servicing," I agree it needs to be done in a manner that prevents unnecessary interference. But I do not see that other areas such as all other junction boxes like those behind the fire alarm device, therefore, become exempt from the labeling requirement because other trades are not there. Please comment!