Original article from 2008.
A company which specialises in the manufacture of sensitive insulation monitoring devices and on-line earth fault location systems for the healthcare sector is using the latest Cropico instrument to test the electrical safety of its installations.
Cumbria-based Bender UK, part of the German owned Bender Group, has equipped its mobile service engineers with DO4002 digital ohmmeters to ensure that earth loops are less than 0.1 ohm when commissioning and servicing electrical equipment.
The lightweight units are very portable, making it easier and quicker for engineers to check the safety of hundreds of Bender isolated power system installations in operating theatres, cath labs, MRI rooms, CT scanners located throughout the UK.
Bender has specified the DO4002 to enable it to comply with New Medical Electrical Installation Guidance Notes (MEIGaN), which cover the safety requirements of electrical systems installed in diagnostic imaging, patient treatment and radiotherapy rooms.
This guidance includes buildings, refurbished rooms and transportable diagnostic or treatment rooms and requires the measurement of resistance between each protective earth terminal, socket outlet or every accessible metal part and the earth reference bar in patient medical environments.
In the revised guidance, a minimum test current of 1A is now permitted and the maximum acceptable resistance is 0.1Ω.
Bender’s project engineer Gary George said that the DO4002 has fulfilled all expectations and has been impressed with its performance.
He added: “It’s an excellent instrument, which makes it easy for our engineers to undertake the safe electrical testing of our products regardless of where they are located.
“Nothing compares with it in terms of portability and design function. All in all, it’s an impressive and unique product that will make the job of electrical safety testing a whole lot easier.”
The DO4002 enables users to meet the earthing and equipotential bonding tests required by MEIGaN and has been specifically developed for this type of electro medical installation testing.
A special lightweight design and single push button test operation, with a large direct reading display of measured values allows maximum ease of use and total portability.
Importantly, the tester is battery powered which means that readings can be taken without the risk of earth leakage currents from the main power supply interfering with resistance measurements.
In addition, the availability of extended lead lengths of up to 20 metres means that room sockets are all accessible from a single point and individual plug tests can be undertaken fast and effectively.
The rugged DO4002 incorporates a number of advanced features to ensure measurement accuracy including forward and reverse current measurement with auto averaging, true current zero, long scale length and a selectable measurement range from 4mΩ to 400Ω with respective resolutions between 1µΩ and 100mΩ.