seperating household consumption and 'generated' power


Unfortunately, I'm not able to install current clamps on both the "produced" power and the "consumed" power. The only option I have is to install a current clamp on the total power. I do have an in circuit meter ("GSC" counter) available, so I wonder if it would be possible to properly seperate both powers by taking into account these 2 measurements.
So to resume:
clamp 1=power as close as possible to my energy supplier
GSC output=generated output of the PV installation (type EM10din)

Is the device capable of graphing (clamp1-GSC power)? Are they measured synchronously?



icarus75's picture

Hi Johan,

The key thing is to have the cable feed from the PV invertor directly attached to the output of the differential switch (or main breaker in case you do not have one). See David's blog post for a clear schema and explanation:

Most installers connect your PV feed 'somewhere' in your breaker panel. In such a setup, 'production' and 'consumption' are mangled together. You will not be able to separate these anymore with a current clamp.


ghostgum's picture


The current clamp sensors used by Flukso don't distinguish the direction of current flow. So you can have the following scenarios:

Sensor reads 400W. House uses 100W. Solar inverter generates 500W.

Sensor reads 400W. House uses 900W. Solar inverter generates 500W.

In both cases, the sensor and inverter are the same, but the house consumption is different. Measuring the household net power |house load - inverter generation| and the inverter generation is not sufficient. You do need the sensor in the correct place.

I had the same thought as you earlier this year, but worked out (as above), that it doesn't work.

jokke's picture


Indeed.. Amazing I didn't realize this immediately. It shows that basic stuff sometimes needs attention :-)
It even took me several DAYS to realize!!

Still need to do some modifications to my fuse box to be able to monitor household power...


Stijn's picture


I recently bought a flukso and want to install it so I can measure my household consumption and my solar panels. To do so I must adjust my fuse box but I have a question about this : the differential switch (300mA) is 40A so the thickness of the output cable is 6mm². When I attach the cables from the solar panels to the output of the differential switch, the max. power that can go through the cables is 65A (40A from the power net and 25A from the solar panels). Does this mean that I have to change my cables that connect the output of the differential switch to the different circuits from 6 to 10mm² ?

Hopefully my question is clear,

bazzle's picture

300ma? 30ma.
I would say no as the max current thru the sw does not increase.
It is just offset by the solar output.
Also depends on how it wired?
Maybe att a link to a cct diag..


bazzle's picture

It will still offset the load. You need to connect 'generated " power to the most loaded phase.
Ive only ever wired single phase solar in so somebody else can help hopefully?


llksta's picture


I just had this discussion with my "keurder"' the answer is yes and more.....

With a 40 amp per phase supply and a 16 amp protection on the pv producer you have a theoretical possible fault load on your differential and cabling of 56 amps,

It was made clear to me that I must install a primary (300mA) diff rated at 63amps luckily I had already wired my board and the main feed with 10mm cable so no extra work there.

What I hadn't been made clear on before was that the dif doesn't trip at it's rated load I.e. It's not an over current protection. That still surprises me but I had the same advice from two independent keurders.

Note this applies to Belgian legislation / systems and may not be relevant in other parts of the world.

llksta's picture

Sorry I meant to say 40 + 25 = 65 that would mean in theory an even bigger diff, than 63 amp.

bazzle's picture

I cant see how the current would increase thru the switch. The power from the solar would offset the load so less current would flow at that time solar was inputting.
When no load the max 'reverse' current would be the solar output.
Normal full load current would be the same from the direction of the mains supply source?