Martindale, Model BZ701 Socket Tester 230V ac RS Calibration

The Martindale Socket tester & supply polarity checker not only detects 28 socket wiring fault conditions and checks the mains voltage level, it also safely detects Line-Neutral reversal (cross polarity) at the incoming supply. The polarity swap test detects a serious fault condition that cannot be identified by normal socket testers on PME / TN-C-S systems, the most common type of supply.

Incoming supply cross polarity test
Quick & easy mains socket testing
High/low voltage indication