Socket-See-DL420-Plus-Loop-Testing-Kit-Socket-See-SOC-DL420 Plus-P-The-DL420-will-test-for-No-trip-loop-High-current-True-Loop-Impedance-No-trip-PFC-Prospective-Fault-Current-High-current-PFC-using-True-Loop-Impedance-mains-voltage-L-N-L-E-&-N-E-&-correct-socket-wiring-P-P-Another-unique-feature-of-the-DL-420-tester-is-high-current-2-wire-measurement-of-TLI-True-Loop-Impedance-Regulations-&-guidance-books-refer-to-loop-impedance-measurements-but-up-until-now-loop-tes