I picked up an Iammeter WEM3080T with intentions of monitoring my mains coming in. I am in the US, and this unit does split phase (Since we are only 2 phases IIRC). I did forget that I have 400 amp service though (2x 200 amp panels). This would mean I need two WEM3080T to monitor both panels, correct?
No instructions with this unit, I assume I just put power to the top ‘UA’ pin and neautrl to the ‘UN’ pin?
Edit: Documentation shows this:
AC input: UA-Live wire Phase A, UB-Live wire Phase B, UC-Live wire Phase C, UN-Neutral wire
How do I wire this up then with 2 phase?
Doesn’t this require a DIN Rail and isn’t it for 3 phase? Do you have 3 phase into your house/business? If not then I don’t think this is going to work.
They’re not very clear on how to use this device on split phase setups, they just say it’s supported. But it’s probably pretty straightforward. UA, UB and UC each go to the phase you’d like to measure with the respective clamp (IA, IB and IC) and UN is neutral. The Ix clamp measure current, the Ux entries measure the corresponding voltage and possibly phase. All that is needed to compute accurate energy values. The meter itself doesn’t care much which phase it is (you could even have the same phase on multiple U entries). You just need to make sure that each clamp is on the same phase as it’s U entry.
So in a split phase system (which is just a 180° two-phase system, rather than a 120° three phase), UA goes to phase 1 live and the IA clamp around the phase 1 main wire. UB goes to phase 2 live along with the IB clamp. UC and IC can stay unused or you can connect them to either of the two phases for a second measuring point on the phase (maybe some individual leg you’d like to have more details about). UN is neutral, which is common to both phases.
The only caveat is on the software side. If the meter doesn’t measure the phase shift between the Ux inputs (but only the voltage), then you might have to specify the phase setup in the software, or the energy calculations may be wrong.
These type of meters work on any number of phases, you could even mount them on a single phase system with 3 different legs. The only thing that changes is the phase difference between the individual inputs: 0° on single phase, 180° on split phase and 120° on three phase.
I don’t have one of these, but looking at their instructions, I tend to agree with HeyImAlex.
Your breaker panel should have the split phase coming into the breaker panel along with Neutral. In that sense its very much like their 3 Phase diagram except you just don’t use the “C” portion to monitor incoming power. You could alternatively use the “C” portion to monitor a 120VAC load circuit.
Very helpful, thanks guys. Unfortunately if I want to do whole house it looks like I need a second unit. Then that is the trick of how do I add up the values in Home Assistant to show up as one.
As for powering this thing up. In their video it shows them sistering a smaller gauge wire in a breaker. Pretty sure thats against NEC here in the US. I would assume the best way would be to either junction off another circuit outside of the panel or run a dedicated circuit. The former seems cheaper, easier.
The UI looks awesome but I wish the instructions were a bit more clear.
Not too sure what you’re seeing, but they’re pretty explicit about where to place the meter in terms of breakers on their quickstart guide. And that’s a pretty typical setup using a dedicated circuit only for the meter with its own dedicated breaker.
Not too sure I’m following with why you’d need a second unit. So you’re having two panels with two independent 240V split phase circuits ? If so, you’d need to monitor 4 live phases (2x2) and you’d indeed need two units. You could probably use a template sensor for adding the values in HA.
As for NEC compliance, well, the unit is intended to fit onto a DIN rail. As far as I remember, DIN rails in residential breaker boxes are not NEC compliant (but I have seen them used extensively in industrial systems in the US, so idk, maybe that changed). So you might have to find a way to mount it outside of the main breaker box, as you said. Over here our main breaker panels are all based on DIN rail, so a module like that one would just clip on with it’s dedicated breaker sitting right next to it.
Hope this drawing helps. Not my panels or meter but its the same thing at the end of the day.
I have 400amp service at the meter base. From there it branches off into two 200 amp panels. Seems like I need to add a new double pole breaker into each panel for the UA and UB connections, UN ties into my neutral bus. IA CT and IB CT clamps go on my mains coming into each panel. Rinse repeat for each panel.
I think the best bet honestly will be for me to get a new box with a DIN mount inside (Either factory or I will add one) to house the two iammeters. From there run conduit to each panel so no exposed wire. Should be clean and safe. Sound like a solic plan?
Yeah, your circuit diagram is exactly the way I would wire the units. Double pole breakers are important since you’d switch both phase legs. Over here we also switch the neutral through 4pole breakers (3 phases + N), but I guess that’s not commonly done in the US.
Damn 400 A, what kind of house is that That’s more than the 3 phase supply we have powering our entire farm lol
Sounds good ! Probably the cleanest way to handle this.
All electric and a custom built house. Previous owner did run a small hobby wood shop so he had a decent amount of 30amp double pole needs. Appreciate the help on this! I will have to do a cost/benefit of the whole system; another iammeter, DIN box, breakers, etc.
Nice to hear other users around! No to Buffalo, but I am in Maryland.
I got it working on a temp setup. I did not like it slapped in the panel though so I will need to get a DIN enclosure. I wanted to prove it out before I got a second unit for my other panel. The little wifi antenna even in the enclosure is showing -68 dBm which is a GREAT signal. Panel in the basement, access point on floor 1. Helps it is 2.4GHz only.
I think the end result for me will be to get an additional WEM3080T, a DIN enclosure to house both, and then whatever fittings/conduit/wire I need to hook it all up. I am using the cloud option to prove it out but also have it in HA. I did have to whip up some light YAML to add up meter A and meter B to get me the aggregate.
I mounted couple of the WEM3080T’s in HT-5 enclosures. Got the first one off eBay, and got the second off Amazon.
One is connected with 3/4" conduit , and the other was with two 1/2" conduits. Difference being available knockouts. One 1/2" would be tighter than I like.
Not sure about the HT-8, there is also an HT-10. There is probably a spec somewhere. I have two WEM3080T’s mounted in an 8x8 metal junction box that I got from Home Depot. I pop riveted a DIN rail in that one. Plenty of knockouts in the junction box.
Would you mind sharing yaml to aggregate A&B?
Would be ideal if they had a two channel meter, and had an entity for combined A&B powre.
I too just bought an iammeter unit. I have a 3 phase system with no Solar. I can get it going in the card section. And graph each phase independantly but unable to get a graph to add each phase into one. I am also struggling to get it set up in the energy tab of Home Assistant. What code did you use to get it setup.
I have attached my setup. Here in Oz the common enclosure you get at any electrical outlet fit perfectly.
I think you can make a sensor template to sum wem3080t_power_a + wem3080t_power_b + wem3080t_power_c. Then you could display total watts. I need to actually learn how, I am new.
Here is what I came up with. This is put into configuration.yaml. sensor.panel_1 is the name of my iammeter. Since I will be needing a second for Panel 2 I was trying to think ahead.
As for the Energy tab, I wished it was there as well but I have not done a ton more research into that. To me that would be beneficial if I had solar. I just combined it so I can get an at-a-glance card of Panel 1.
That’s more than the 3 phase supply we have powering our entire farm lol
