Description
xShelly Pro 3EM Switch Add-on, Galvanically Isolated 2A Dry Contact Relay for DIN Rail
The Shelly Pro 3EM Switch Add-on adds a galvanically isolated relay output to a Shelly Pro 3EM energy meter. It clips onto the side of the meter on the DIN rail, so a single unit can both measure consumption and switch a contactor or other low current load.
The potential free contact switches up to 2A at 240V AC or 2A at 30V DC. It is designed for control circuits and light loads rather than direct switching of heavy appliances. A Shelly Pro 3EM is required and is not included.
Key Features
- Add-on module for the Shelly Pro 3EM only, connected through the Shelly proprietary add-on interface.
- Galvanically isolated, potential free (dry) relay contact with separate input (I) and output (O) terminals.
- Switches up to 2A at 240V AC or 2A at 30V DC.
- Powered from the Shelly Pro 3EM at 3.3V and 12V DC, with power consumption below 1W.
- Internal temperature sensor with temperature reporting.
- Two red LED indicators: Power (supply connected) and Out (relay contact closed).
- Slim 19mm wide housing that mounts on a DIN rail alongside the Pro 3EM, with a double mounting bracket supplied.
- Screw terminals for 0.5 to 2.5mm² solid, stranded or bootlace ferrule conductors.
Product Overview
The Shelly Pro 3EM measures energy on up to three phases. On its own it reports what is happening; with the Switch Add-on fitted it can also act on that information. The add-on gives the meter a relay output that can be controlled locally or through automations, for example energising a contactor when consumption, export or another condition is met.
The add-on replaces the mounting bracket on one side of the Pro 3EM and plugs into the meter's header connector. Both devices then sit on the DIN rail as one assembly, held by the supplied double bracket. The add-on takes its power from the Pro 3EM, so no separate supply is needed.
Because the contact is isolated from the meter electronics, it can switch either an AC circuit up to 240V or a DC control circuit up to 30V. The manufacturer lists resistive, capacitive and inductive loads as supported, including contactors, transformers and fans, with an RC snubber shown in the wiring guidance for inductive loads. With a 2A limit, larger loads should be switched through a correctly rated contactor driven by the add-on.
Applications
- Driving a contactor from a Shelly Pro 3EM based on measured consumption or export
- Switching small resistive loads such as indicator lamps or small heating elements
- Low voltage DC control signals up to 30V, such as an inverter or controller enable input
- Residential consumer units and multi dwelling buildings
- Light commercial, agricultural and industrial energy monitoring and control panels
What Is Included
- 1 x Shelly Pro 3EM Switch Add-on
- 1 x Double DIN rail mounting bracket
- 1 x Printed user and safety guide
Installation and Safety Notes
Compatibility: this add-on works only with the Shelly Pro 3EM, which is sold separately. It does not work as a standalone switch.
Installation must be carried out by a qualified electrician in line with BS 7671 (IET Wiring Regulations). Isolate the supply and confirm with a voltage tester or multimeter that there is no voltage on the Pro 3EM terminals before fitting the add-on or changing any connection. Take care not to bend the header pins when joining the add-on to the meter.
Connect the load circuit to the O terminal and the neutral, and connect the I terminal to a suitably rated circuit breaker. A neutral conductor is needed for the switched load circuit. Never exceed 2A at 240V AC or 2A at 30V DC; use a contactor for anything larger. Solid single core conductors are recommended, stripped 6 to 7mm, with terminal screws tightened to no more than 0.4Nm.
The add-on has no published IP rating and must not be installed anywhere it can get wet. Fit it only inside a dry indoor consumer unit or enclosure, within an ambient temperature of minus 20°C to 40°C and 30% to 70% relative humidity. High voltage is present on the add-on interface when the device is powered.
Specifications
xModel Information
| Parameter | Value |
| Model | Shelly Pro 3EM Switch Add-on |
| Manufacturer | Allterco Robotics EOOD (Shelly) |
| Compatibility | Shelly Pro 3EM only (not included) |
| Device interface | Shelly proprietary serial add-on interface |
Electrical Specifications
| Parameter | Value |
| Power supply voltage AC | N/A |
| Power supply voltage DC | 3.3V and 12V (from Shelly Pro 3EM) |
| Power consumption | < 1W |
| Inputs | 1 x load circuit input (I) |
| Outputs | 1 x load circuit output (O) |
| Potential free contact | Yes (galvanically isolated) |
| Max switching voltage AC | 240V |
| Max switching voltage DC | 30V |
| Max switching current AC | 2A |
| Max switching current DC | 2A |
| Supported load types | Resistive, capacitive, inductive |
| Internal temperature sensor | Yes |
| LED indication | Power (red), Out (red) |
General Specifications
| Parameter | Value |
| Dimensions (H x W x D) | 94 x 19 x 69mm (±0.5mm) |
| Net weight | 20g (±1g) |
| Mounting | DIN rail, attached to a Shelly Pro 3EM |
| Conductor cross section | 0.5 to 2.5mm² / 20 to 14 AWG (solid, stranded, bootlace ferrules) |
| Conductor stripped length | 6 to 7mm |
| Screw terminal max torque | 0.4Nm |
| Shell material | Plastic |
| Colour | White |
| Ambient temperature | minus 20°C to 40°C |
| Humidity | 30% to 70% RH |
| Max altitude | 2000m |
| Installation location | Dry indoor location only (no IP rating published) |
Certifications
| Parameter | Value |
| EU declaration of conformity | 2014/35/EU (LVD), 2014/30/EU (EMC), 2011/65/EU (RoHS) |
| Markings | CE, RoHS, WEEE |
Return Policy
xWe offer a 14-day, no-quibble returns or replacement policy because we want you to be totally satisfied with your purchase.
If you are unhappy in any way with your purchase, you can return it for a refund or a replacement, as long as you return it in the same condition as it arrived (original/undamaged packaging and product) and within 30 days of receiving it. We will pay for your return postage on a faulty item as long as you send it using Royal Mail 2nd class recorded delivery (for EU or International Shipments, you have to use our UPS account, we will provide you with a return label)
Please keep in mind the following:
- Items returned within 14 days but not in their original and undamaged packaging will also incur a -15% charge per package.
- If you return an item that doesn't adhere to our returns procedure or doesn't include a returns form, you may be liable for a £10 administration fee
- Individual items from a bundle can't be returned, refunded or exchanged. If you want a refund/credit/exchange for a bundle, all items must be returned to us.
Before you return your item, please make sure that:
- You follow our returns process (outlined below)
- The goods and packaging are undamaged
IMPORTANT: We need to be able to identify an item with your order. We can only do this if you follow our returns process. Please do not send us items back that do not follow this process as they cannot be identified properly and will not be replaced or refunded.
What delivery method do I need to use when returning an item?
You must send the goods back to us via Royal Mail 2nd class recorded delivery. Refunds on faulty items returned are reimbursed within 5 working days.
Can I return just one item from multiple purchases?
Yes. Once you start the returns process you will go to a page that will allow you to choose which items you want to be replaced or refunded.
Returning faulty goods
If your item is faulty, you need to follow the returns policy, where you will be able to state that it’s faulty. The product will then arrive at our warehouse for testing.
If your purchase is not within 14 days
You can still exchange your item for a different product or for credit to use on the Voltacon Solar or Ledison-led-lights.co.uk websites (-15% from the credit amount).
Returns outside of the 14-day period do not qualify for the free returns policy.
Returning an item within the warranty
If you have a warranty and want to return a faulty item, you just need to follow our standard returns process. When we receive your item, we will then check that it’s within warranty and for any faults before arranging a replacement.