Electric Vehicle Charging Open PEN Protection
Reliable & Durable “Fit & Forget” Units
UK Design & Manufacture
On & Off-board Switching Options
Advanced Sensing & Fault Monitoring
Flexible and Tamper-proof Configuration
Fully BS7671 Compliant
An open PEN scenario is when the combined Protective Earth (PE) and Neutral (N) conductor to an electrical installation goes open circuit but the Live remains connected. It is an unusual event (approx. 400 reported per annum in the UK), but the consequences for EV charging is potentially serious. Any loads that remain on drag the vehicle body towards live presenting a serious shock hazard. In the latest edition of the IET wiring regulations, the specific safety concern over an open PEN conductor for Electric Vehicle Charging was redressed. A race to get products to market occurred with units appearing for stand-alone use or with the required function integrated. We have been contacted for our technical opinion on these units. We could immediately see multiple improvements that could be made to function and particularly reliability. As a result, we launched an internally funded product development earlier in 2020 during the CV19 lockdown.
We are in an advanced stage of development on a range of devices for domestic, commercial and on-street applications. We have decided to call the units PEN-Guard®. They will be designed and manufactured by our very experienced and ISO9001 accredited sister company Smart Power Solutions.
We have listened to what installers want – a simple and reliable unit they can “fit and forget”. We fully understand that just one additional site visit can cost the installer dearly. Rigorous product validation tests are being carried out to ensure reliable trouble-free operation. Full product launch is anticipated in early March 2021 with limited trial units available before that.
Features which we believe are
unique to PEN-Guard®
- Use of high-quality components from suppliers known for long-term reliability.
- High-integrity durable low-resistance earth path
- Active detection of sensing faults and high-resistance earth path
- Simple but flexible configuration at point of install with tamper prevention
- Low operating power consumption
- Advanced relay switching technology to reduce inrush current and extend contact life
- Specific design measures to reduce nuisance tripping:
- High accuracy voltage measurements allowing trip limits to be set very tightly
- Advanced digital signal processing for robust real-world measurements
- Trip memory and reset delay to prevent an intermittent PEN conductor going unnoticed
- Indication of last fault even if power is cycled.
- Automatic testing and manual testing via push button
- Clear indication of status and faults via LEDs
- Current Transformer input with adjustable trip threshold. This can be used for limited capacity
- installations to ensure correct load sequencing
- Trip status output (For commercial or on-street applications)
- Smallest units with on board relays (32A 1 Phase 5 DIN Wide and 3 Phase 6 DIN Wide)
- Same advanced technology in smaller footprints and reduced cost for use with external contactors. This
- should allow operation up to 400A per unit in 1 or 3 phase configurations
- Robust metal housing for DIN rail mounting (to be used with IP54 plastic enclosure)
- 3 year warranty with aim to extend that to 5 years+ once results of long term accelerated life testing is available.