The new MFT1721 multifunction tester (MFT) from Megger is a versatile and cost-effective choice for contractors whose work includes commercial and industrial installations that have three-phase supplies.

As well as providing all of the facilities needed for testing low-voltage single-phase installations in line with the IET Wiring Regulations, this innovative instrument can also check phase sequence, evaluate prospective short-circuit current up to 20 kA, perform phase-to-phase loop testing at 415 V, and test three-phase RCDs even when no neutral connection is available.

Additionally, the MFT1721, which is one of the new models in Megger’s popular and successful MFT1700 range, offers valuable extra features, including: true RMS voltage measurement, facilities for testing the Type B RCDs and a millivolt sensor input. It also features fast-response continuity testing at 200 mA or 15 mA and, with an optional current clamp accessory, it can be used to measure current.

The MFT1721 has a timesaving automatic RCD test facility, and can test RCDs with sensitivity ratings between 10 mA and 1 A, including programmable types.

Like all instruments in the new MFT1701 range, the MFT1721 provides three options for loop testing – two-wire no trip, three-wire no trip and high current – which means that the fastest and most convenient method can be used in every situation.

A large, bright, dual-parameter display shows the test voltage at the same time as insulation resistance.  Loop resistance is displayed at the same time as prospective fault current. Tests are selected quickly and positively using clearly marked colour-coded control knobs – there are no complex and confusing menus to navigate.

Safety is central to the design of MFT1700-series instruments. They are dust and rain proof to IP54 rating, and they have a CAT IV 300 V safety rating, which means they can be used without concerns in any environment. The instruments also incorporate comprehensive protection against damage if the wrong range is selected or if they are accidentally connected to a live circuit, even if the test has been locked on.