u/kevmekk

Adding local Zigbee/Home Assistant on/off control to two bathroom fan heaters. My electrician will install it — I just want to spec the right parts first. Hoping someone's solved this exact combo.

Setup:

• 2× Ouellet OVS0500BL wall fan heaters (fan-forced: motor + element), 500W @ 240V (~2.1A each)
• 240V split-phase, two hot legs, no neutral in the box
• Each has a working built-in dial thermostat
• Separate 15A double-pole breakers, Square D Homeline panel (Canada)

Plan: set the dial to a high-but-reasonable temp and let HA handle regulation via smart on/off of the circuit. So I'll also need a temp reading per bathroom (probably a standalone Zigbee sensor driving an HA automation). Open to better ideas.

Preference: I'd rather use a hidden Shelly-type relay than a wall thermostat — the thermostat's required wall location is an issue for the wife.

What I've ruled out:

• Shelly + 2-pole contactor: clean, but the Shelly still needs a neutral to power itself → blocked
• Shelly on 240V (L2 into N): I've seen a post on Reddit that says it voids warranty / not rated → avoiding
• Smart breakers: none that are Homeline-compatible + CSA-certified + local HA

On the neutral: might be able to pull one from a nearby switch, and the run could be 14/3 with a capped neutral hidden in the box (wiring is <3 yrs old) — both to be confirmed during the visit.

Questions:

1. Any Zigbee/Z-Wave relay that switches 240V split-phase and powers itself from the two hot legs, no neutral needed?
2. If not — is running/borrowing a neutral to feed a Shelly + contactor the realistic path?
3. Assuming worst case (no neutral): what would you buy?

Thanks!

Adding local Zigbee/Home Assistant on/off control to two bathroom fan heaters. My electrician will install it — I just want to spec the right parts first. Hoping someone's solved this exact combo.

Setup:

• 2× Ouellet OVS0500BL wall fan heaters (fan-forced: motor + element), 500W @ 240V (~2.1A each)
• 240V split-phase, two hot legs, no neutral in the box
• Each has a working built-in dial thermostat
• Separate 15A double-pole breakers, Square D Homeline panel (Canada)

Plan: set the dial to a high-but-reasonable temp and let HA handle regulation via smart on/off of the circuit. So I'll also need a temp reading per bathroom (probably a standalone Zigbee sensor driving an HA automation). Open to better ideas.

Preference: I'd rather use a hidden Shelly-type relay than a wall thermostat — the thermostat's required wall location is an issue for the wife.

What I've ruled out:

• Shelly + 2-pole contactor: clean, but the Shelly still needs a neutral to power itself → blocked
• Shelly on 240V (L2 into N): I've seen a post on Reddit that says it voids warranty / not rated → avoiding
• Smart breakers: none that are Homeline-compatible + CSA-certified + local HA

On the neutral: might be able to pull one from a nearby switch, and the run could be 14/3 with a capped neutral hidden in the box (wiring is <3 yrs old) — both to be confirmed during the visit.

Questions:

1. Any Zigbee/Z-Wave relay that switches 240V split-phase and powers itself from the two hot legs, no neutral needed?
2. If not — is running/borrowing a neutral to feed a Shelly + contactor the realistic path?
3. Assuming worst case (no neutral): what would you buy?

Thanks!