MPS Electrolysis Blocker-Galvanic Isolator

  • Model: MPSEB100
  • Manufactured by: L&B


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Marina Protection Systems Electrolysis Blocker

Marina Protection Systems' award winning Electrolysis Blocker is designed to address the corrosion problem that occurs when dissimilar vessel hulls and/or structured materials are electrically connected to a common ground.


  • When vessels are isolated from different electrical potentials, the electrical potential (emf.) is allowed to equalise, resulting in a mass decrease in the metal ion transfer rate (corrosion).
  • Rated to 67A and meets the stringent AS/NZS test standards for fault current of up to 5000A
  • Note: *Galvanic Isolators are now recommended in the latest AS/NZS standards

    How It Works

    Vessels in a marina are interconnected via the common shore earth which carries low voltage DC current between them and the marina.

    This DC current is passed through the metal through hull fittings in to the water where it is free to contribute to galvanic corrosion. The result is more rapid consumption of anodes and then damage to unprotected submerged metal parts.

    An Electrolysis Blocker™:

    Blocks the damaging DC current

    Maintains effective AC earth capability

    Standards AS/NZS3004.2.2008 & 3820:2009

    ABYC A-28

    Marine ISO 8846

    Installation Instructions The MPS Electrolysis Blocker must be installed by a licenced Electrician.

    * The Electrolysis Blocker must be used in conjunction with a circuit breaker rated up to 16A max (minimum 5KA fault rated) and a 30mA residual current device.

    The diagram below shows the general arrangements for electrical supply to a vessel with blocker installed. Further information can be obtained in Appendix B of AS/NZS3004.2

    The Electrolysis Blocker shall be connected into the supply protective earthing conductor before it connects to the boats earth system. It should be installed where there is protection from accidental access, good ventilation, as close as practical to the shore power inlet / distribution panel and behind the appliance inlet. Use the mounting slots on the Blocker to secure it. The Electrolysis Blocker is installed in series in to the earthing conductor, the Blocker is clearly labelled “Ship Earth” and “Shore Earth”. The terminals of the Blocker should be treated as live parts.

    The information stickers provided must be affixed in plain view on the front of the distribution panel.

    Maintenance Instructions

    The MPS Electrolysis Blocker does not require service or maintenance as it contains no moving or serviceable parts.

    Boat owners are required to obtain an Electrical Warrant Of Fitness (EWOF) for all vessels with hard wired 240VAC electrical systems.

    MPS recommend inspection periodically by a licenced electrician to ensure earth terminal connections remain secure and the unit stays properly mounted.

    Electrolysis Blockers can be tested for performance and/or fault conditions by a qualified electrician using a multimeter.

    The MPS Electrolysis Blocker is designed and sold for the purpose of galvanic corrosion protection and must not be used for any other use.

  • This product was added to our catalog on Tuesday 15 July, 2014.

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