I previously raised a thread about using Emporia CTs but as this is specific to extension leads I raised a new one. I have read a few other comments from you on here about extension leads but this is a bit different.
I have an external meter box and internal sub panel. I want to measure the mains from the external box because the HWS is taken from there. Also room in the internal sub panel is tight. The problem is the metre box is 27 metres (cable length) from the internal one.
I have run Cat6 cable (22AWG solid copper) and am getting consistent reasonable results. It is only run near other cables for a short distance.
BUT … the Emporia CTs I am using are voltage type and I am wondering if voltage drop across that distance will give me inconsistent results. Which would give better consistency with high vs low consumption … current types or voltage types? I doubt any CT will see 50 amps.
From the Emporia thread I am still experimenting with Cal values. Fortunately I temporarily have CTs on the mains at both internal and external panels so can compare the effect of that long extension. With the CTs at the internal panel set at Cal 750 I get an almost identical reading from the external CTs if I set them to about 900.
- I have not changed the Phase lead (all set at 2). Should that be increased for those on the extension?
- Should I swap these external CTs for current type? The local Iotowatt supplier is out of stock so I was thinking of these:
SCT-013-000 CT: 100A = 50ma - Should I use the 2 wires in each of the 4 twisted pairs as one conductor, thus doubling the copper? i.e. The Cat6 cable then has 4 conductors and I would run a second cable so I could have 4 CTs there - 3 for the 3 phase plus the HWS.