Euchun ECS16100

I’m also in Aussie.
The post below has the OP trying to source the preferred Euchun CT clamps for the “low” amp curcuits, he linked to the part ECS1050-L59E Euchun part number which seems to be 50/50mA output with the 3.5mm audio connector.

I have bought some SCT clamps for the “main” amp inputs @ 100A, but I assume that the Uchen ones are better, so will try and source those at the same time. So the basic model seems to be ECS16100 (16mm hole with 100A rating) but what output should I get. ie 100/??ma options are 20/33.3/40/50/100/1000mA

Checking out tables.txt shows the config is


So I guess its twice the turns, twice the 50ma of the ECS1050, so am I right at 100ma, ie 100/100mA ?

(Sorting out an Australian three-phase installation):

I’ve not actually got my iotawatt unit yet, waiting for shipping from openenergymonitor, but trying to get the parts organised ahead of time.


Actually its the opposite. Twice the turns, half the current. So using a ECS16100 (with 2000 turns) to measure 50A gives a 25mA output current produced by the CT. Using the same CT to measure 100A provides 50mA output.

You are best to get the 50mA output CTs for whatever primary current you are interested in.

A 50A primary and 50mA output CT (ECS1050) has 1000 turns (eg 50A in/1000 turns = .05A or 50mA out)

A 100A primary and 50mA output CT (ECS16100) has 2000 turns (eg 100A in/2000 turns = .05A or 50mA out)

The 50mA output current provides the full range of voltage across the 24ohm (or 20ohm) burden resistor in the Iotawatt on each CT input for the ADC to sample. The Iotawatt uses the turns ratio parameter to scale the output current of the CT (represented as a voltage across the burden resistor) into the correct current being measured.

You can use other ratio current CTs but need to configure a different turns ratio and either will not get the full voltage range into the ADC or will get an excessive voltage if you are not careful. If buying new CTs then no advantage in getting anything other than 50mA output.

The maximum input current to IoTaWatt is 50mA. All of the CTs sold at the stuff site have 50mA output at their stated primary current. So the ECS16100 is 100A/50mA, and both the ECS1050 and ECOL09 are 50A/50mA.

If you tell me what you are looking for in terms of how many 100 and 50 Amp CTs, I can quote shipping to Australia. Since you already ordered your unit from OEM, you can’t take advantage of the $20 flat rate shipping from the stuff site as others down there have.

For example, since you can get a decent AC adapter and USB power supply locally:

1 IoTaWatt @ $119(US)
3 ECS16100 @ $11 = $33
6 ECS1050 @ $6.38 = $38.28
2 ECS1050 @ 8.50 = $17
Total $207.28
Flat Rate Shipping $20
Total $227.28(US)

Great thanks for the responses, should of bought from USA but just assumed Europe… dang it!! especially as they are shut until next week. Might try and cancel…

So i have aussie three-phase power, I’ve got the Jaycar VT and will try derived setup to start with.

The only thing that appears to use all 3 phases is my air-con unit. From a monitoring point of view I don’t think I care about the current (should I??) for each phase, only the total draw across all phases. So 2 questions…

  • Can I just put a single CT over all three wires… (BONUS and use 1 channel vs 3 channels)
  • If so, there doesn’t seem to be a way to specify “All” phases in the CT config

I ask the above question as it will determine what clamps I’ll buy from your store…
Probably 4 ECS16100 (1 for each phase, + 1 for all phases on aircon)
Then 10 ECS1050 for the remaining channels

Thanks a lot

Sorry Tim, it doesn’t work like that. You would need three CTs into three inputs to measure Total AC draw. That said, if everything is on phase A, then the power through mains B and C should be equal to the power to phase B and C of the AC. So you can use a 100A CT on mains phase A, and 50A CTs on mains phase B and C, and a 50A CT on the AC phase A. You can then configure an output for the AC that adds the AC PHase A and the mains B and C.

Bottom line is you still need only 4 CTs for the mains and AC, but 1 100A and 3 50A.

Better double check that only the AC is on B and C though.

Anyway I think the circuits are distributed over the 3 phases…

I’ll try and cancel my open order with OEM and then just order the whole shebang from you…
Will find out on Monday…


@overeasy I cancelled my order with OEM and ordered with you.

Looking forward to getting this installed.