MSEL Master Relay

£439.00£484.00 (+VAT)

The MSEL Master Relay is a battery isolator that goes much further than just safety in mind. It has been designed with the sole purpose of a motorsport environment. Utilising solid state  switching components, the Master Relay has excellent temperature resistance, as well as an  aluminium enclosure that is lightweight and robust in even the harshest motorsport environment. The device not only has built in engine shutdown functionality in accordance to FIA regulations, it also incorporates alternator load dump protection unavailable on most rival devices. This helps to avoid nasty voltage spikes often seen when disconnecting the battery source whilst the alternator is still charging.

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This MSEL Master Relay can safely shut down the vehicle under a number of different events including: external kill switch press, over current / short circuit, over temperature, and can even be shut down via a remote CAN message. For example, in the event of a severe impact or an overturned.

When connected to a data logger on a CAN bus, the Master Relay provides valuable information about the current, voltage and internal temperature, as well as diagnostic information that makes finding problems a lot easier. As well as transmission to a data logger the Master Relay has a multi-coloured LED that shows a unique colour combination for each of the 10 different states. The driver switch can also be connected with an LED to show when the battery is isolated.

Available with either AutoSport or Serial connectors, please make your selection whilst adding the Master Relay to the basket in the options above.

MSEL Master Relay Specification:


  • Interface Connector: 8STA6-04-06SN
  • Battery Terminal: Copper plated M6 Stud
  • Output Terminal: Copper plated M6 Stud


  • Supply Voltage(Vs): 8V / 30V
  • Operating Current (ls):
    • Normal: 0.03A
    • Isolated: 0.02A
    • Standby: 0.01A

PDM/ECU Output

  • Drive Type: Configurable
  • Output Voltage (On): Vs
  • Output Current (Max): 200mA

Switched Current

  • Maintained Current: 200A @ 25 ℃
  • Peak Current: 1000A


  • Rating: IP63
  • Operating Temperature: -20 to 100 ℃
  • Weight: 115g
  • Dimensions: 99 x 70 x 28mm

Download Files


Download MSEL Master Relay User Manual


Download MSEL Master Relay Quick Start Guide

Here at Northampton Motorsport, we also offer a full wiring and fitting service as well as engine calibration on our in house Superflow AD30 2 wheel drive chassis dyno. For more information, please contact us and a member of our team would be happy to assist with your enquiry:

Contact Us

All ECU’s are configured to order so the lead times can vary. Estimated dispatch time within 10 working days.

Picture for illustration purposes only. Actual parts may differ slightly in appearance.