Which statement correctly describes how End of Line resistors help the panel differentiate faults?

• A. The panel uses the current level to indicate a fault
• B. The panel uses a known resistance to differentiate open versus short conditions
• C. The panel relies on voltage drop across the loop
• D. The panel ignores EOLR in fault conditions

Answer: (B)

End of Line resistors establish a definite reference value at the end of the supervised loop. The panel continuously reads the loop’s resistance and expects it to match the known End of Line resistor value when everything is normal. If the line opens, the circuit appears open and the resistance becomes very high; if a short occurs, the resistance drops to a low, predictable value. By comparing the measured resistance to the expected end-of-line value, the panel can differentiate between an open fault and a short fault. That’s why using a known resistance to distinguish open versus short conditions is the correct idea. The other options don’t describe how EOLRs provide that distinction, and EOLRs are not ignored during fault conditions.