Shelly Pro 3EM Switch Add-on 2A Dry Contact Relay DIN Rail

The Shelly Pro 3EM Switch Add-on fits onto a Shelly Pro 3EM energy meter and gives it a galvanically isolated relay output. Clipped onto the DIN rail beside the meter, the pair can measure consumption and switch a contactor or other low current load from the same assembly.

The potential free contact switches up to 2A at 240V AC or 2A at 30V DC, suiting control circuits and light loads rather than direct switching of heavy appliances. A Shelly Pro 3EM is required to use it and is sold separately.

Key features of the Shelly Pro 3EM switch add-on

• Connection, plugs into the Shelly Pro 3EM through the proprietary add-on interface.
• Contact type, galvanically isolated, potential free, with separate I and O terminals.
• Switching rating, up to 2A at 240V AC or 2A at 30V DC.
• Power draw, powered from the Pro 3EM at 3.3V and 12V DC, under 1W.
• Monitoring, internal temperature sensor with reporting, plus Power and Out LED indicators.
• Housing, 19mm wide, mounts on DIN rail with the supplied double bracket.

Product overview

On its own, the Pro 3EM reports energy data across up to three phases. With the add-on fitted it can also act on that data, energising a contactor when a consumption, export or other condition is met. The add-on takes the place of the bracket on one side of the meter and draws power from it, so no separate supply is required.

Because the contact is isolated from the meter electronics, it can switch an AC circuit up to 240V or a DC control circuit up to 30V. Resistive, capacitive and inductive loads are all supported, including contactors, transformers and fans, with an RC snubber recommended for inductive loads.

Applications

Driving a contactor from measured consumption or export, switching small resistive loads such as indicator lamps, or carrying a low voltage DC control signal up to 30V into an inverter or controller enable input. Suited to consumer units, multi dwelling buildings, and light commercial or industrial monitoring panels.

Installation notes

This add-on only works with the Shelly Pro 3EM, sold separately, and is not a standalone switch. Fitting should be carried out by a qualified electrician to BS 7671, with the supply isolated and tested dead before working on the terminals. It has no published IP rating, so it must be installed in a dry indoor location only.

What's included

• 1 x Shelly Pro 3EM Switch Add-on
• 1 x Double DIN rail mounting bracket
• 1 x Printed user and safety guide