Larger Load Control

So I have a couple of large loads i need to control.
My first solution is with a 30A Contactor with a 240V Coil.
You have the 30A Contactor and a Sonoff Basic running a 240VAC.
So here is the problem. Where do you integrate them.
At the panel? Problem is the contactor is not enclosed and you end up with live
terminals exposed. The other problem is it takes up alot of space.
Could use and SSR but they get to hot. The other issue is how well does a sonoff or similar
product work enclosed in a metal box. I thought about building something with an 8266 but then
I need a power supply and will end up with another device that takes up to much space.
I am looking for idess.

have a look at this:

I have one running my big A$$ compressor...


What are you trying to run? USA 240V or not?

There are purpose built high amp switches that probably would work without all the hackery.

Can’t go wrong with Aeotec:

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The Aeotec linked above by @bcopeland will also handle 240VAC, 2 phase.

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That Aeotec is going to be tough to deal with when you are using the 10ga wire required for your 30 amp circuit . Many reviews point out that the plastic case and strain reliefs are not up to handling that wire. I use the GE for my pool pump and it comes in a sturdy metal box (like the Intermatic timers) with multiple knockouts that take standard 1/2" and 3/4" fittings.

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What kind of load are you trying to control? Resistive 30A is a little easier to find than ballast or motor.

i was giving this some thought and unless I'm missing something - there is likely a cheaper option than buying a dedicated zwave high amperage relay.

Most dry contact relays have a control voltage. some 24v others 120v.
then there is the dry contact - clearly need to buy what ever voltage and current rating required...but these seem relatively inexpensive

Couldn't a lower power Zwave dry contact relay like the zen 16 be used to drive the control voltage for a high amperage higher voltage stand alone dry contact?

Seems to me that a single 40a Zwave dry contact relay is 100 or more where as a zen 16 and 3 high amperage dry contacts would be less than that for a total of 3 relays.
Or am i missing something?


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My 10ga wire works fine, not sure what people had issues with...

Well sure, if you want to roll your own it could be cheaper...

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Call me crazy, but I like knowing an electrical engineer designed the stuff I have controlling line voltage (especially 240) as opposed to a guy like me that just plays one on tv.


I have a dust collection system in my woodshop that is almost exactly what you describe here. The box and relay came with the system but I added the receptacle and Zibee (ST) plug-in switch.

That's a 5HP, 220V single phase motor fed the standard way through the relay which has a 120V coil. The receptacle is wired to one leg of the 220 just like it is in your main power panel if your in a US residence.

Not that it matters but just to be complete I use a Z-wave Aeotec Nanomote to operate the plug-in switch. Works a champ!


If you are going to DIY I cannot recommended RIBs enough!

I used to install them when doing old Boiler and chiller takeovers.

I dont have any plans on doing this as i have a pool controller BUT 1Zen 16...30 bucks. 3 of the high amperage relays 120 for all 3 Plastic outdoor rated enclosure...20 bucks. for 170 you have a 3 discrete high amperage dry contacts......whats not to like:)

Thanks for all the ideas.
Here is where I am. I was looking for a cost effective solution for large loads, no more then 40a at 240vac.
I cant see spending $100+ on a high current device.
I have 9 tasmota devices that I can use to energize either a relay or a contactor.
My problem is space. The contactors are quite large and the relays, its tough to find a 2 pole 30a device. I can go with a single pole device but makes the terminating end dangerous.
So for around $15 I can control up to 40A. My other choice is building my own board with 8266 and relay.

Steve - if the dust collector in your woodshop looks that good, I would love to see the rest of it!


$100 seems like a small price to pay for a UL rated, properly engineered device that is capable of handling ~9600 Watts of power. This is not a trivial amount of power to be dealing with. As an Electrical Engineer, I recommend you 'buy vs build' in this instance, due to safety concerns. I love DIY projects, but I try to limit those to low-voltage DC circuits where the risk of electrocution and fire is extremely low.

Please make safety your number priority in whatever you decide.


@LosinIt Me too.

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Thanks for the responses
Bought 2 RIB 01P30 new for $27 on ebay.
Electrical contractor for 40+ years


Just thought I would post this picture. Replacing cracked PVC box with x10 gear in it).
UL Listed PVC Box and UL Listed 30a DPST relay ($8).
4 Port WIFI/433MHz smart switch not UL Listed (CE).
Mounted on a DIN rail.
Dock Lights, Landscape Lights, Pool Light and Pool Pump.
Trivial amount of power? 0.2A can kill you.
So not to worry if you don't know what your doing don't mess with it.
By the way not everything the we purchase and install has the UL stamp of approval.
Check out you all of you devices that use electricity. May be CE, ETL, CSA, UR and there are plenty more testing groups and standards, but it doesn't have to have the UL insignia to be sold and installed in the USA .