Independent study explains why RootWave technology is the safest electrical weed control

A study has shown that RootWave’s patented 18 kHz electrical weed control is safer than 50Hz or DC devices, by orders of magnitude.

In 1891, Jacques-Arsene d’Arsonval found that using high frequency alternating electric current significantly reduced the likelihood of serious injury from electric shock.

The study on RootWave’s technology built on this and undertook extensive literature searches, modelling, and analysis to assess the severity of injuries a person could sustain from electric current. The conclusions are consistent with d’Arsonval, and show that ‘operating electrical weed control devices at around 20 kHz is much safer than operating lower frequency devices (including DC)’.

RootWave’s patented higher-frequency eWeeder is 10,000 times less likely to cause cardiac arrest than a device using standard 50Hz AC in the event of accidental contact with an electrode. For DC devices, RootWave is 2,500 times less likely.

The design of the product is intended to minimise the risk of someone coming into contact with live eWeeding electrodes, but this study gives assurance that RootWave high frequency technology is significantly less harmful should that unlikely scenario occur.

Safe use of electricity

The study, completed in 2022 by professors who work for AMC Consulting and Imperial College, London found that operating at around 20 kHz gives ‘substantially greater opportunity to increase the power levels of the equipment without causing ventricular fibrillation (arrythmia of the heart/cardiac arrest), should a person come into direct contact with the electrodes.’ Concluding ‘It is thus advisable to operate weed control devices in the region of 20 kHz.’

Graph: The Y axis shows electrical power, the X axis shows frequency (log. scale) with green (low) and red (high) denoting the risk of ventricular fibrillation (cardiac arrest). This shows RootWave can operate at high powers with relatively low risk. [each listing reffers to full exposure to a single eWeeding module]

Frequency, in electrical terms, is simply how many times the current oscillates from positive to negative per second. Standard 50Hz electricity oscillates 50 times per second, at 18kHz it is 18,000 times. Direct Current (DC) has no oscillation.

International patents

RootWave has patented this technology in all major markets.

Founder and Head of Research Robert Diprose says: “Our technology is cutting edge. Fundamentally the concept of driving electricity around a circuit that includes the weed the ground and then the return is relatively simple.

“However, we do things differently, we use waveforms that are intrinsically safer, we use control systems that allow us to manage every joule of energy that flows through the system in real time, then we put wrap around safety protocols on our systems to ensure that accidental injury is unlikely to occur.”

The study is helpful in explaining why RootWave’s patented waveforms are safer. Initial results from trials with RootWave’s tractor-powered eWeeding machine in sugar beet, maize and apple crops also show that the technology can provide full control of a range of weeds.