I am looking for a device to monitor the power consumption for my dryer.
There are plenty of devices for 120 v up to 15 AMP which come in form of plugs or smart switches that also monitor.
But there seems to be nothing to monitor the 240V 30 AMP connections we have here in North America. The wire sizes required by code are 10/3 and would just fit into a Sonoff or Shelly switch. The problem is that such a switch would need to handle 30 AMP but the closest I can find is the: Shelly 2.5 Relay Switch that can handle 10 AMP per channel max.
Is there someone out there that has successfully installed a consumption monitor for a dryer?
It would be nice if someone can help me with this problem.
Look at the Shelly EM2 50 Amp coils, mount on the main panel (breaker for the dryer). It just monitors the power, no switch. I wouldnāt put a switch on a dryer.
Are we talking about an industrial class dryer? I canāt imagine a consumer class dryer pulling that much power.
Are you sure the dryer is that powerful? Or is the power socket simply capable of providing as much?
I have not seen a consumer class dryer on the market (in Europe) that pulls more than 2 or 3kW. For those a 20A (even 16A) smart plug with energy monitor should be fine.
I monitor my dryer with a 16A smart plug. It pulls less than 10A @ 230V.
If its really a high power 30A dryer, than indeed a coil-type power monitor would be the solution.
In Canada, residential electric dryers are typically protected by a 30A breaker (two 30A breakers, one for each half of the split-phase). In other words, if thereās a short in the dryer, all load wiring will experience 30A of current before the breaker trips.
If you install a device in the circuit thatās incapable of handling 30A then, effectively, it becomes the ābreakerā (and a potential fire hazard). Thatās why chrisbklein is looking for a device capable of handling the maximum current level.
I think the challenge you will face is that contactors rated to handle 240VAC 30A arenāt cheap so this drives up the deviceās overall cost. Plus, if I understood correctly, your application isnāt for turning the dryer on/off but just monitoring its energy consumption. Therefore youāre paying for spendy contactors that you donāt actually need.
In contrast, a 120VAC 15A relay is cheap. A few years ago I bought about a dozen energy-monitoring smart plugs from Costco (on clearance) for about $6 each. I flashed them with Tasmota and one is used to monitor energy consumption of the dishwasher and another for the gas furnace.
I definitely donāt need to ever remotely turn these appliances on/off (theyāre programmed to automatically turn on the load on power-up). In other words, the relay is unused and I only employ it for energy-monitoring. However, for $6 itās not like I overpaid for the unused relay; itās a cheap way to get energy-monitoring. However, I doubt the same value proposition can be realized for a device able to safely handle 240VAC 30A.
The usual way to monitor a 240VAC dryer, stove, oven, hot water tank, pool pump, AC, etc is by using an energy-monitoring device connected to the load via a CT clamp. Thatās what lordwizzard suggested (although that particular device isnāt rated for 240VAC). Search for āEmporia Vueā to get an idea of a āwhole homeā version thatās able to monitor multiple circuits.
That depends on how the 240 is brought into the structure. Normally a transformer at the pole brings 2 120 VAC legs and common (neutral) into a home structure and panel. Most use a single switched double breaker for protecting both legs (wires), any problem on a leg, trips both sides to off. Other buildings may bring in 240 on a leg, so that is 480 VAC service. Then they step up to 3 phase 480 VAC service. They are removing a lot of older mixed services (less efficient and harder to balance loads) for the simpler one (more efficient and easier to load balance) mentioned above.
The EM 2 with the proper coils will handle/measure up to 120 amps. The 50 amp coils should be able to monitor any normal service for a dryer/range/etc that uses 240 VAC
