You won’t be shocked by us!
14 September 2022
Carlo Gavazzi has launched the DUA55 a single-phase relay for detection of incorrect mains voltage. It is designed to meet the specific requirements set out in the IET Wiring Regulations, BS7671:2018, to ensure that all new EV charge points are electrically safe.

The relay operates when the monitored voltage is within the voltage window 207V to 253V AC in order to protect against over and under voltage; its alarm output has also been fixed at four seconds to comply with the regulations. Stopping any incorrect power supply voltage from the desired one.
Only 17.5mm wide and is suitable for both rear- and front-panel mounting on a single-phase EV charging unit or a separate box, this will ensure the user is protected against electric shock if the PEN were to become damaged.
The relay sends an output signal to the EV charger to tell it to electrically disconnect the vehicle from the live conductors of the supply and from protective earth within five seconds (in accordance with Regulation 543.3.3.101(ii)), in the event of the utilisation voltage at the charging point, between the line and neutral conductors, being greater than 253V rms or less than 207V rms.
For additional safety, the relay can only be reset if the voltage between line and neutral conductors is in the range 207 to 253V rms.
Carlo Gavazzi’s DUA55CM44BXXX single-phase monitoring relay is practical and cost-effective at preventing electric shocks with residential EV charging stations. It eliminates the requirement for additional earth electrodes whilst improving the overall safety of the charge point installation.
The DUA55CM44B006 is approved by CE, and UK CA.
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