I5 Residual Ground Current Calculation for 1PH3W LL with N connection

[BrandonReed]

I have a PM8000 installed on a 120/240V single phase system. I have 3 CTs, one installed on each line, and one installed on the neutral (wired as shown in the attached picture).

I was expecting to see a residual ground current calculated as G= -(L1+L2+N) appear on the PM8000 internal webpage, but the value is always 0.000A. When I manually calculate the residual current using the magnitudes and angles from the phasor view, I get between 0.10A and 0.34A (depending on the instantaneous load). 

Tech support indicated this setup should work, as well as some unofficial confirmation from this post. 

Can someone point me in the right direction to get this working?

Thanks!

[Charles_Murison]

Hello @DanL 

Do you know if the meter's calculation for I5 changes if meter is in Single Volts mode?

Regards,

Charles

[DanL · Accepted solution]

technically "no", but practically (in most cases) "yes"

in "Single" volts mode, there are two main categories of wiring CTs on the PM8000 family:

a) 2 CTs on each of two hot current carrying conductors (wired to I1 and I2. I3 not connected)

b) 1 CT on one hot current carrying conductor (wired to I1 only. I2 and I3 not connected)

For either case, if I4 is wired to an additional CT on a Neutral conductor (or I4 is wired as a summation of the other CTs as shown in a technote), then I5 is the (calculated) residual ground current, otherwise I5 is the (calculated) residual Neutral current

[BrandonReed]

Hi @DanL, I have the meter wired per method (a) as described in your post, which also matches the wiring diagram I attached to this thread. However, I am not seeing any values populate for I5 on the meter's internal webpage (see other images attached to this thread). Can you point me in the right direction of what to check?