Grade 2 13.8V DC. This Grade 2 boxed power supply from Asec has a powder coated steel construction and 13.8VDC regulated output with anti tamper features and a hazard warning label. EN50131 – GRADE 2 Intruder systems that require monitoring of the mains and battery. Featuring deep discharge protection and integral battery charging facility this is a safe choice of power supply with LED indicators and switch mode technology.. Anti tamper features. Switch mode technology. EN50131 – GRADE 2 Intruder systems that require monitoring of the mains and battery. LED indicators