MW9420 earth/resistivity meter

MW9420 earth/resistivity meter: overview

The MW9420 allows earth measurement by several methods: standard method (with stakes), selective method (with a clamp, optional), 2-clamp method (optional) and leakage-current measurement (optional clamp), as well as soil resistivity measurement. Particularly suited to cathodic protection measurements, it can be accompanied by a Soil Box on request.

Its new housing concept is compact and rugged, with a graphic LCD display, a PASS/FAIL light indication, rechargeable battery power (20 h life), a built-in magnetic support for hands-free work, 50 V CAT IV safety and RS-232 and USB interfaces. It is supplied with a mains adapter, 6 NiMH batteries, 4 earth stakes, 2 cables of 4.5 m and 2 cables of 20 m, and a manual. Optional accessories: clamps (leakage current, current), lead kits, 50 m measurement kit, carrying bags and reporting software.

Its role in cathodic protection

Before designing protection, you need to know the soil: its resistivity indicates how aggressive it is and guides the choice of anodes and groundbed. The MW9420 measures this resistivity in the field. Once the system is in place, it is also used to check the resistance of earth electrodes and groundbeds, whose increase reveals ageing.

Why several methods

The stake method gives the reference measurement. Clamp methods avoid disconnecting an earth electrode in service, which matters on an operating site. Leakage current measurement helps locate unwanted current flows.

MW9420 earth/resistivity meter: technical specifications

MW9420 earth/resistivity meter: documentation