Measuring usage on several 15 / 20 amp circuits?

Other Devices & Integrations Power Management
#1

Is there product out there that I can use to monitor several 15/20 amp circuits at breaker panel. I have an Aeotec ZW095 on the main lines. More ZW095s would be costly and because the clamps are so large would be unworkable in a tight box on small 12/14 gauge wires.

Really looking for a smaller type unit with maybe 4 or more clamps for specific circuits. Googling has not found anything that I could use with Z-Wave.

#2

do you want to measure them individually or all together?

#3

Individually

#4

I don’t think you will find any thing with smaller clamps.
https://store.zwavecenter.com/index.php?route=product/product&path=79&product_id=715
You could use wall insert relays with power monitoring, at other end of the circuits. This would also give you the option to turn circuits off.

#5

Not sure if it is supported, but Qubino has a zwave Smart meter https://qubino.com/products/smart-meter/

#6

There are solutions, but nothing really off-the-shelf within reason.

I’ve done branch circuit monitoring in data centers with products like these below, but they are not inexpensive, and generally use ModBus or similar interfaces and so would require considerable additional effort to interface to Vera:

https://www.pdicorp.com/products/monitor/bcms-kit/#1528307353541-0da5e1ec-6ed6d0d4-53d9dcd0-69cd5e3a-3ac8

The retrofit kits, for existing panels (these are typically otherwise built in to the power distribution system) are usually a logic board with a number of split core CTs that you wire to the logic board–open the CT, clamp it around the wire, connect to board, and Bob’s Your Uncle. It just comes at a horrifying cost.

You could do a “poor man’s version” by using CTs like these: https://preview.tinyurl.com/rmxkt2a (preview URL for your comfort/security)

These units output a conditioned 4-20ma (other versions 0-10V, 0-5V, etc.) signal in proportion to current, so you’d need to come up with an interface for them that the Vera could reach.

An even cheaper solution on a per-circuit basis would be create the entire thing from scratch using bare CTs, like these: https://www.amazon.com/Current-Transformer-DROK-Transformers-Sensing/dp/B01LWN37KS

These particular units output a current proportional to the current of the monitored circuit. Bare CTs like this need to be handled very carefully, though, as they can induce substantial, dangerous voltages across their secondaries–you do not want to be handling the ends of the wires when the thing is wrapped around a live circuit. But, as you can see from the unit cost of the CT itself, if you are capable of building the interface, you can get a lot done for the cost of one of the above “pre-fab” 4-20ma units.

For either the “pre-fab” 4-20ma unit or the bare CT, the hardware interface isn’t difficult: Ohm’s Law lets you convert the output current range signal to a voltage range signal, and feed that voltage to (example) a NodeMCU’s A-D pin to convert the analog voltage signal to a digital value. Scale to range, and there you are. Vera queries the NodeMCU over WiFi.

BTW, for testing if high-current appliances are running, IMO it is much safer to use a split-core “pre-fab” unit with binary output (just a different version of the 4-20ma that has switch contacts that close or open when current sensed exceeds a settable threshold) than a Z-Wave “appliance” plug–I’m just too paranoid to believe the ratings and certifications on those products.

1 Like
#7

I’ve been swamped with my day job for last couple of months and didn’t get a chance to respond when this was first posted. I agree with everything @rigpapa says and would simply like to reinforce his comments on safety. I don’t know your background @ElCid, and don’t want to offend, but working with AC mains voltages can injure, kill or start fires if this is new territory for you.

I agree 100% with the above. Also, FWIY, controlling and monitoring high-power electrical loads has been part of my day job for the last 40+ years and I’d do as @rigpapa suggests. Easier and safer!

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#8

@HSD99 I am sorry what dangerous thing did i suggest?
IF479 seems confident about fitting thing in his circuit box, and if he isn’t i think would call in a expert, or his dodgy pal down the road. What ever he does is his choice. I just offered an opinion on what he could use.

I certainly did not tell him to do any thing dangerous.

#9

I simply wanted to make the point that working with AC mains can be dangerous.

#10

So why mention me like i know nothing about ekectrikery.
You don’t know me at all.

Again i ask what did i say that was dangerous?

#11

I’m sure that you will find that z-wave switch metering inserts do not exist in 15-20A.
If your looking at a modbus solution as @rigpapa suggested then you might like to look at Homeseer which has a modbus plugin.

edit: Another but expensive solution would be to use KNX modules, but that is heading away from Vera and again would need HS to monitor and control.

#12

ZW078-B/C rated at 40a for 20a 230v

or

Fgs211 rated to switch 16a at 230v (edit/ this model does not have power monitoring)

if 120v then any insert rated at 2.5kw would work on a 20a circuit, but don’t exceed the switching capabilities. just because a circuit is rate 20a, does not mean it is pulling 20a. It may only need to switch 10a.

Just for the anal these are the max ratings and i would advise not to run any device at max for extremly long periods.

there are also z-wave sockets and plug in sockets again you need to check load values and types.

#13

Sorry I have been offline for last day and a half(ish). Yes I am comfortable working in electric panels I guess I should have stated that up front.

The qubino was almost there, but i couldnt any of their products rated over 10a. Its frustrating when I can see all kinds of info in the server rooms I work in (yes I know commercial world, different things, in this case snmp enabled power strips and outlets).

For the moment, would be great to monitor power usage of the mini split heat pump I installed to handle a small addition to my house. Its 110v on 15a circuit, quick check with fluke clamp shows anywhere from 2a to 8a when running.

The unit is a pioneer that has a wifi dongle that i installed on it that connects back to the company and on my phone I have an app that can control it. Unfortunately I cant even get actual run time from the app. Their stats show how many hours the unit was turned on, which is useless. Have already pinged on them about the fact they cant show any real usage. (may be that that info is not available via the wifi but firmware updates can do wonders) I probed the device to see if it responds to anything other than a ping and it remains silent. May still work on reverse engineering that later.

I may just buy one of those other units like the " Emporia Vue Smart Home Energy Monitor with Expansion Module" wifi enabled to report back and you use an app on the phone to get data (supposedly 1 second intervals). Just leave it separate from the vera and at least can use that to zoom in on the circuits of interest and watch over time. ($99 and its working on my android)

thanks for all the suggestions.

#14

aoetec also do 3 phase power monitors, which have 3 clamps. You could then monitor 3 circuits

A cheap solution non z-wave

try a sonoff pow 2. you can export the data. Also you could monitor it via node-red and communicte with vera via node-red.

#15

Between pow and node-red you could have me off on a tangent having fun for weeks… lol this is really cool looking. Thanks for the tip.

#16

Yep node-red will have you tinkering.