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Has anybody used these matt-e products for EV charging points?

Former Community Member
Former Community Member

Is this brand any good ? 

The supply source is a three phase T-N-C-S system. The load on the three phase distribution board is never going to be fully balanced so the options are to either to install earthing rods (electrode) or use one of these devices to avoid hammering rods to be compliant.

Just wondered if anyone had any experience with the brand.

Any other ideas also welcomed.

Regards,

J

 

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    Any out of balance current on a three phase 4 wire system returns via the neutral conductor, not via the earth rod.

    Not during a broken CNE event - hence the OP is looking at an option from 722.411.4.1.

    Banging in rods isn't likely to be a sensible option to keep things below 70V unless you've got remarkably low N currents, or the site is on a salt marsh. 

    There are several makes of EVSE that offer ‘broken PEN’ protection of varying sorts.  Note that the type that works by measuring the L-N voltage (option iv) are only permitted on single-phase installations (since on 3-phase installations better results can be obtained by measuring against an artificial N derived from all three Ls).

    The other option of course is to create a TT island for the charge point - although that means ensuring it's out of reach of anything connected to the TN earthing system - which isn't always easy.

       - Andy.

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  • 0

    Any out of balance current on a three phase 4 wire system returns via the neutral conductor, not via the earth rod.

    Not during a broken CNE event - hence the OP is looking at an option from 722.411.4.1.

    Banging in rods isn't likely to be a sensible option to keep things below 70V unless you've got remarkably low N currents, or the site is on a salt marsh. 

    There are several makes of EVSE that offer ‘broken PEN’ protection of varying sorts.  Note that the type that works by measuring the L-N voltage (option iv) are only permitted on single-phase installations (since on 3-phase installations better results can be obtained by measuring against an artificial N derived from all three Ls).

    The other option of course is to create a TT island for the charge point - although that means ensuring it's out of reach of anything connected to the TN earthing system - which isn't always easy.

       - Andy.

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