### Ct 2 is 88% too low

hello, I use EmonTX shield and 2x SCT 013-000 CTs 100A and AC 9V and sketch for CT1234.
Ct 1 working properly
Ct 2 is 88% too low, indicates 800 watts, normally 1500Watt.
what's wrong?

### Re: Ct 2 is 88% too low

hello, I use EmonTX shield and 2x SCT 013-030 CTs and AC 9V and sketch for CT1234.
Ct 1 working properly
Ct 2 is 88% too low, indicates 800 watts, normally 1500Watt.
what's wrong?

### Re: Ct 2 is 88% too low

I have no idea what is wrong at this point. All I can suggest is you adopt a logical approach and check all the possibilities.

First of all, which c.t. are you using - you posted twice with different versions listed. The 30 A one has an internal burden resistor and you should not have fitted the 33 Ω resistor in each of the input circuits. The 100 A one does not have an internal burden and the 33 Ω resistor should be fitted.

Is it the c.t. or the input circuit in the shield, or the sketch?

1. Are you using one of the standard sketches and have you changed the sketch? If you are using a standard sketch and you have not changed it, it is not likely to be that.

2. You have 4 inputs. Use the same c.t. in each input and with the same current flowing, do all 4 read the same, within 2%? If they do, the problem is not the input.

3. You have 2 c.t's. Use the two c.t's in the same input and with the same current flowing, do both read the same, within 6%? If they do, the problem is not the c.t. If they don't, post again and I'll tell you what to check next.

If (2) and (3) don't show where the fault is, I'm puzzled. Has the fault now gone away? The jack sockets are often very stiff when new and you might not have pushed the plug fully home.