Author Topic: 240v Heater module  (Read 498 times)

Offline jeubanks

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240v Heater module
« on: March 22, 2018, 09:05:05 pm »
Trying to find a basic on/off inline module that will safely work with standard 240v wiring (no neutral) and handle at least 10 amps.

I have seen a couple that state 120v and require a neutral, but I have yet to find a 240v module I can wire in.  This is for an in-wall heater in the bathroom.

Anyone have any ideas?

Offline kwieto

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Re: 240v Heater module
« Reply #1 on: March 23, 2018, 07:10:44 am »
As far as I know, the only devices which go without neutral are dimmers.
Are you sure you're not talking about ground (yellow cable)?

For standard installation (hot and neutral cable) Philio and TKB made some 3kW (12A) switches (no power reporting, as far as I remember). You may also try to find old Fibaro 1 relay switch (3kW = 12A), they are still to be found on e-bay etc (new or used). If you have enough space, you can put a relay with desired parameters between your z-wave switch (input) and heater (load).
You may also try to use new Qubino and Fibaro switches, they have 10A capacity, but I wouldn't recommend that if your heater is rated exactly 10A. Fist, current at the edge of switch capacity may damage it in the long run, second, it my happen that your heater takes more than it declares (I've found that my 2kW heater takes in fact 2.2kW in peak, which may be important difference for choosing proper relay.

A device like this one: https://www.ebay.com/p/Crydom-A2425-Solid-State-Relay-Input-VAC-Output-VAC/1928979896?iid=382330323523

This is also recommended to steer high power consumption devices in general, as high power tend to damage relays over time (and you then replace only the additional relay which is cheaper compared to replace z-wave switch).
« Last Edit: March 23, 2018, 07:16:46 am by kwieto »

Offline rigpapa

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Re: 240v Heater module
« Reply #2 on: March 23, 2018, 03:20:45 pm »
You could also use a definite purpose contactor (aka big relay), running it from a Z-wave switch (select one with a 120V coil, and wire the coil as you would a light fixture). It will generate less heat in use than the SSR, most likely. An SSR driving a multi-KW load is going to need some ventilation, but the contactor will be more tolerant. It's not hard to find contactors with very high current ratings. Example: https://www.grainger.com/product/EATON-120VAC-Definite-Purpose-Contactor-49C076

Contactor or SSR would have go to in an appropriate enclosure.
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Offline HSD99

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Re: 240v Heater module
« Reply #3 on: March 23, 2018, 05:35:15 pm »
You could also use a definite purpose contactor (aka big relay), running it from a Z-wave switch (select one with a 120V coil, and wire the coil as you would a light fixture). It will generate less heat in use than the SSR, most likely. An SSR driving a multi-KW load is going to need some ventilation, but the contactor will be more tolerant. It's not hard to find contactors with very high current ratings. Example: https://www.grainger.com/product/EATON-120VAC-Definite-Purpose-Contactor-49C076

Contactor or SSR would have go to in an appropriate enclosure.
Second the recommendation to use a contactor as opposed to SSR. I would suggest using a Z-Wave switch with a mechanical relay output, as opposed to solid-state, to drive the contactor coil.

Offline jeubanks

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Re: 240v Heater module
« Reply #4 on: March 29, 2018, 09:05:56 pm »
Thanks for the input on the contactor.  I'm also going to pass this along and bug an electrician buddy on it.