R9MCT80 Schneider Resi9 Current Transformer Kit 80A Six Pieces PowerTag Energy Meter Distribution Board

The R9MCT80 is the accessory that determines whether a Resi9 metering installation is accurate. It is supplied as a set of six 80 A transformers because the meters it serves have six channels. Each transformer clips around a single conductor up to 10 mm in diameter and passes a low-level signal to the meter, which allows the meter to sit on 27 mm or 36 mm of rail instead of occupying the space of a direct-connected device.

The green front in Pantone 355C is not decorative. In a board that also carries protection devices, a coloured identifier on the metering accessories prevents a transformer from being moved or re-clipped during later work and left on the wrong circuit.

The technical guidance for this part is almost entirely about what not to do. A transformer must close around one conductor only, so a group of parallel feeds needs one transformer per conductor or a different metering approach. A transformer fitted around a cable bundle measures the vector sum and produces a number that cannot be reconciled with anything.

The 80 A rating is a saturation limit rather than a working current, and the meter expects the 80 A transformer to correspond to its 80 A configuration. Mixing an 80 A transformer with a meter set up for a 160 A or 250 A range will scale every reading by a fixed factor and look like a calibration fault.

Because the set contains six pieces and a three-phase circuit uses three, the same kit can serve two three-phase circuits or six single-phase circuits. This should be stated in the offer so the quantity is not doubled by mistake.

Sets of six 80 A transformers are used wherever six single-phase circuits or two three-phase circuits are metered in one board.

• Domestic consumer units: applied to lighting, sockets, kitchen, water heating, heat pump and a spare way — the pattern that answers most household energy questions.
• Small offices: the same six-way split on a three-phase board.
• Retail units: lighting, refrigeration and general power where the overnight profile matters.
• Workshops: separating machine sockets from general power.
• Landlords: where a shared intake has to be apportioned between tenants.

In refurbishment, the set is often bought before the meter, because the transformers are the part that has to be fitted while the board is open. A meter fitted later to transformers already in place is a ten-minute job rather than a shutdown.