Megohmmeters can test for the most common loop issue - a cut in the insulation which causes the loop to short to ground. Megohmmeters are the only meter that can test for the common issue of a slight tear in the insulation. This is why they have the nickname "Insulation Testers". This analog megohmmeter gives installers more information that the typical light up megohmmeters. The pin will point to the megohm reading, which then gives you a number you can record and monitor to determine if the loop is shorting to ground.
The BD Loops Analog Megohmmeter Loop Tester Includes:
In-depth Instructions for Testing Loops
Quick Start Instructions for Testing Loops
Testing Record Booklet - Track loop performance and protect your installation.
To have a megohm reading simply connect one lead of the megohmmeter to the loop and connect the other lead of the megohmmeter to ground.
Are you testing your loops with the right meter?
To accurately "meg" a loop you need to use a megohmmeter and not a multimeter. Due to the fact that multimeters have an "ohm" setting many installers falsely believe that a multimeter can be used to "meg a loop". Multimeters and megohmmeters differ by:
multimeters typically measure Continuity, Voltage, and Resistance. (Loop multimeters will check continuity, but won't tell you if the loop is shorting to ground.)
Megohmmeters are Insulations Testers. (Megohmmeters will let you know if the loop wire's insulation has been cut and is causing a short to ground.)