Electrical Industry Awards 2021

Electrical Safety First –
Safety Innovation of the Year Award 2023

Read about HobSensus on pages 104-107 in the latest issue


Hob power cut-off system

Key features

  • 4 Settable run times - 15, 20, 30 or 120 minutes
  • Two selectable modes - ON/OFF or Auto-On
  • Simple on/off button activation
  • Power, active, pre-trigger and alarm LED’s
  • Standard 2 gang fitment
  • Sensor Head is mounted on the wall above the hob
    Power Switching Unit is mounted below the worktop
  • Supply voltage - PRE9279PSU - 230V~ 50 Hz.
    PRE9279SH - 6V battery power (4xAA) 5VDC hard-wired.
  • LV Connections - Sensus Head (+)(-), Leak Sensor, Cut-off VFC In.
  • Up to 40 Amp (resistive) capacity allowing
    a maximum loading of 9.2kW
  • Connections - Live in (Lin) 2x Neutral (N) 2x Earth ().
  • Terminal capacity - Minimum 0.6mm²,
    Maximum 13.3mm² cable size
  • Supply Voltage - 230V AC at 50Hz
  • Conformance - EN50615:2015
  • Prefect direct installation service available
    please contact us for a quote
  • 5-year warranty


The HobSensus system comprises two parts, the sensor head (PRE9279SH) and the Power Switching Unit (PRE9279PSU) but is supplied as a single product in one box (product code PRE9279). If you require the unit to be powered by batteries, the battery compartment is an optional extra (PRE9279BC).

This simple to use electronic hob power cut-off system is ideally suited for use in student halls of residence. Its robust design and large switching capacity make it the sensible choice to help avoid risk of accidental fire.

HobSensus observes the cooking surface over 64 zones and monitors the temperature in each zone individually. If the temperature reaches dangerous levels (250°C) the unit will first alert users with flashing amber lights and a beeping sound. If no action is taken and temperatures reach 290°C the power to the hob is cut off. If the person using the hob is distracted the hob will automatically switch off when the run-time elapses.

The user simply presses the red button to activate the hob and start the timer. There are four run times 15, 20, 30 and 120 minutes. For installations where pressing the button is an issue, the Auto-On feature can be set. Times and the Auto-On feature are set via dip switches located on the upper right hand side on the rear of the PSU. There are 4 numbered dip switches. Each dip switch can be either on (up) or off (Down).

Standard set point conforms to EN50615:2015. Low temperature set point can be used for added safety as the unit will switch off at a lower cooking temperature.

The 40A 9.2kW switching capacity allows for a wide range of hobs to be utilised. Installation is aided by large terminals boasting a maximum cable size of 13.3mm². The system also provides both a neutral feed terminal and a neutral output terminal eliminating the issue of doubling up two cables into one terminal.

HobSensus can be connected to third party devices i.e. smoke and fire alarms. When connected to such devices if one unit is triggered it can send a signal throughout the building to turn off all other hobs. If a telecare type system is installed, Hobsensus can call a designated number to inform the receiver that the unit has been triggered, particularly useful for carers or family of those living with dementia.

The timer is moulded in PC/ABS making the timer extremely durable. PC/ABS is fully UV stable and is resistant to cleaning products. A gloss finish overlay makes cleaning easy.

Please Note: This Prefect product is designed to limit the time the hob is powered on and to avoid the risk of fire by switching the hob off before ignition temperatures are reached.

HobSensus Introductory advertisement

HobSensus features video

How to replace the Sensor Head


Product Information


Wiring Diagrams