A multi-function tester (also known as an MFT) is a single, complete unit which is used to carry out a combination of basic electrical testing procedures. It allows the user to perform a range of different tests quickly and efficiently with one piece of equipment and without having to search for and switch to different instruments.
The MFT is used to test low and extra low voltage circuits and ensures equipment and installations are safe and correctly installed and comply with local standards and the 18th Edition rules and regulations. A multi-function tester is generally known as the most essential instrument in any electrical tester’s toolbox.
What does a multi-function tester look like?
MFTs vary in size and functionality but they will usually be a compact, mobile and hand-held instrument with an LCD screen to help the user scroll menus, select tests, operate the unit and read and store results.
There are a wide range of MFTs on the market ranging from basic models which just carry out AC or DC current tests, voltage and electrical continuity tests, to high specification instruments which complete the full range of standard electrical tests and have extra functionality such as temperature probes and better quality or bigger screens. Some units also have Bluetooth and WiFi capability, which allows the user to store, download and share data from the unit to a laptop or mobile device.
What tests do you use a multi-function tester for?
The range of tests that an MFT will perform may vary from model to model, but a standard instrument should allow the user to complete basic tests for wiring polarity, loop and line impedance and phase sequence and rotation checks. A good MFT will allow the user to diagnose any breakdown of the insulation that has occurred in various parts of a standard electrical system such as wires, transformers and motors.
Tests that any MFT instrument should include:
- Continuity tests (or low ohms resistance tests)
- Insulation resistance tests (or high ohms resistance tests)
- Earth fault low impedance tests
- Short circuit current tests
- RCD tests
What do you need to consider when using a multi-function tester?
As with all electrical testing instruments, the key considerations when using an MFT are safety and accuracy. So:
- You should ensure that all equipment and appliances being tested are dead/isolated and remain locked-off in this state while testing is carried out, perhaps using a tag system.
- The user should use a calibration checkbox to ensure routine verification of the MFT, along with maintaining accuracy. This isn’t an alternative to carrying out a formal and independent calibration of the unit on a periodic basis.
Who would use a multi-function tester?
An MFT would be used by electricians and electrical engineers in any commercial, domestic, industrial or agricultural setting, and particularly where a fixed wiring installation has been undertaken.
The nature and design of the MFT is such that it favours a user who has a long series of checks and tests to carry out in a short space of time. Because the MFT combines a number of separate tests and functions in one instrument it is very useful in speeding up testing procedures and making them more efficient, because the user is only using one instrument and doesn’t need to search and set-up another. Furthermore, the MFT is small and mobile and can easily be transported between each testing location.
Video Demonstration
Below is a demonstration video on our popular TIS MFT-PRO Multifunction Tester product:
Please note that this section is for information purposes only. Anyone using equipment referred to in this section must be suitably qualified and/or experienced within the respective field. If in doubt before use, please consult a qualified electrician or engineer & thoroughly read all instruction booklets.