Shelly 1L Gen4 Review: The No-Neutral Relay That Retrofits Any Light Switch
The Shelly 1L Gen4 is a compact in-wall relay built for the one job most smart switches cannot do: adding smart control to a lighting circuit that has no neutral wire. It is a single 220-240 V channel with a 200 W switching rating, and it speaks Wi-Fi, Bluetooth, Zigbee and Matter, so it fits Alexa, Google Home, Apple Home, SmartThings and Home Assistant setups. The trade-offs are the low switching power, no energy monitoring and a wet-contact-only output, which keep it a lighting controller rather than a general-purpose appliance switch. For retrofitting older or awkward wiring, it is a focused and capable option.
- No-neutral retrofits
- Older homes and rental wiring
- Shelly and Home Assistant users
- Matter and Zigbee setups
Pros
- Works with no neutral wire, with the Shelly Bypass for 1L/2L included in the pack
- Four radios in one: Wi-Fi, Bluetooth, Zigbee and Matter over Wi-Fi
- Reaches Apple Home, Google Home, Alexa, SmartThings and Home Assistant
- Acts as a Zigbee repeater to extend the mesh
- Local control with schedules, scenes, scripting, MQTT and webhooks
- Compact in-wall size with overheating and overcurrent protection
Cons
- Low 200 W maximum switching power limits it to lighting loads
- Wet-contact output only, with no potential-free (dry contact) mode
- No energy monitoring
- Single channel, so no interlock mode for motors or shutters
- Zigbee requires a compatible hub; no Thread support
- In-wall mounting only, no DIN-rail option
Who is the Shelly 1L Gen4 for?
It is for anyone who wants smart lighting control where the wall box has only a live wire and no neutral, the situation that rules out most smart relays. The 1L Gen4 powers itself from the live line, and a Shelly Bypass for 1L/2L ships in the pack to sit in parallel with the load, which also removes the minimum-load requirement for low-wattage LED lights. It suits people retrofitting a single light circuit behind an existing switch plate, and because it offers Wi-Fi, Bluetooth, Zigbee and Matter, it works whether the rest of the home runs on Wi-Fi, a Zigbee network or a Matter platform.
What the Shelly 1L Gen4 offers
The headline is no-neutral installation: the device needs only the live wire, and the included Bypass handles the low-wattage LED case that would otherwise flicker or fail. It is a one-channel relay rated for 220-240 V and up to 200 W of switching power, sized at 41.2 x 42.2 x 16 mm and 29 g so it fits behind a switch. Connectivity covers Wi-Fi 802.11 b/g/n, Bluetooth 4.2, Zigbee 802.15.4 (it also repeats the Zigbee signal) and Matter over Wi-Fi out of the box, which is how it reaches Apple Home, Google Home, Amazon Alexa, Samsung SmartThings and Home Assistant. Two switch inputs (S1 and S2) plus a signal output (Sx) let an existing wall switch keep working, and the firmware adds schedules, scenes, local actions, scripting, MQTT, webhooks and over-the-air updates, all with local control. Overheating and overcurrent protection and a three-year warranty round it out.
What to know before you buy
This is a lighting relay, not an appliance switch: the 200 W maximum switching power and the wet-contact output rule out high-power loads and potential-free (dry contact) jobs, so for those the standard Shelly 1 Gen4 is the better fit. There is no energy monitoring, so it cannot report consumption; the Shelly PM models do that. It is a single channel, so it has no interlock mode for two-way motor or shutter control, and it mounts in-wall only, with no DIN-rail option. Zigbee works but needs a compatible hub, whereas Matter runs over Wi-Fi rather than Thread. It is also a new model, so long-term field reports are still thin.
Is the Shelly 1L Gen4 worth it?
If the problem you are solving is a light switch with no neutral, the 1L Gen4 is one of the few relays that solves it cleanly, and the bundled Bypass removes the usual low-load headaches. It gives you the full Gen4 protocol set, local control and broad platform support in a package small enough to hide behind the switch. Buy it for lighting retrofits; if you need power metering, dry contacts or higher loads, step up to the Shelly 1 Gen4 or a PM model instead.
Frequently asked questions
Does the Shelly 1L Gen4 need a neutral wire?
No. It is designed for installations without a neutral wire and runs from the live line alone. A Shelly Bypass for 1L/2L is included in the pack and connects in parallel with the load; it is what lets the relay drive low-wattage LED lights without a minimum load.
Which smart home platforms does it work with?
Matter over Wi-Fi works out of the box, which brings it into Apple Home, Google Home, Amazon Alexa, Samsung SmartThings and Home Assistant. It also supports Zigbee, but that path needs a compatible Zigbee hub.
Does the Shelly 1L Gen4 measure energy use?
No. It has no energy monitoring, so it cannot report power consumption. If metering matters, a Shelly PM model is the one to choose.
How many circuits can it control?
One. The 1L Gen4 is a single-channel relay; the Shelly 2L Gen4 is the two-channel version for controlling two lighting circuits.
What is the maximum load it can switch?
Up to 200 W of switching power at 220-240 V, which suits lighting circuits rather than high-power appliances. It also has overheating and overcurrent protection built in.
