Haydon HAY-PSUEN54-5A is an EN54-4 certified uninterruptible power supply (PSU) for fire-detection and life-safety systems. The boxed unit delivers a nominal 27.6 V DC output with a continuous 5 A rating and includes a built-in battery charger and battery standby/back-up within a tamper-protected steel enclosure. The PSU provides automatic mains-to-battery switchover, battery deep-discharge protection and status reporting via LEDs and a fault relay.

• EN54-4 certified for use with fire-detection / alarm systems.
• Nominal output: 27.6 V DC, continuous 5 A output.
• Built-in battery charger and automatic mains-to-battery switchover; supports typical small enclosure battery fitment (2 × 7 Ah SLA).
• Tamper-protected steel enclosure with mains, battery and fault LEDs; tamper switch and mains-fail / fault relay for remote signalling.
• Electronic overload, short-circuit protection and battery deep-discharge protection; mains transient protection.

Use cases: Intended for fire alarm and life-safety installations in commercial and residential buildings. Suitable for system integrators, fire alarm installers and facilities managers. Not a plug-and-play consumer product — installation must be carried out by a qualified engineer in accordance with EN54 and local regulations.

Compliance & safety: EN54-4 certified (see manufacturer datasheet for full certification details and marking such as UKCA/CE). Follow the supplied datasheet and local wiring regulations for battery sizing, cable routing and earthing. Do not modify the unit — servicing and battery replacement should be performed by qualified personnel.

Notes: Some battery capacity and enclosure sizes vary by Haydon SKU. Confirm the exact enclosure variant and datasheet prior to ordering to ensure correct battery fitment and exact dimensions.