December 23, 20232 yr Hello All Hoping to get some pointers on a problem I have with my Sunsync 8kw system. There is a constant load of 700-900watt on my non essential circuit. If export to CT is off it draws from the grid and if export to CT is on then it draws from the PV. On my non essentials is my geyser and poolpump , both are turned off at the DB when I took the attached screenshots. My installer confirmed the same consumption when testing for the problem but he only had 10mins to quickly look around but sadly he is away for a few weeks The CT coil is roughly 15-20m from the DB board and is connected using the standard cable type and not a CAT5/6 cable Anyone encountered this and can advise on a solution ?
December 23, 20232 yr 1 hour ago, HenryJ said: The CT coil is roughly 15-20m from the DB board and is connected using the standard cable type and not a CAT5/6 cable That needs to be sorted. The CT coil needs to be at the point of entry to your DB. Edited December 23, 20232 yr by Thunderdolt fat firnger
December 23, 20232 yr 11 minutes ago, Thunderdolt said: That needs to be sorted. The CT coil needs to be at the point of entry to your DB. Why? It can be on the cable between the munic and the DB at any point that is accessible or practical.
December 23, 20232 yr 13 minutes ago, Scorp007 said: Why? It can be on the cable between the munic and the DB at any point that is accessible or practical. @Scorp007 @Thunderdolt I keep worrying about this issue of location of CT coil and keep getting various schools of thought. It's not always possible to have inverter close to the DB, which seems to be @HenryJ's and my situation resulting in having to need a long CT coil cable. I've seen some installers put it at the input of the Inverter which seems to be wrong to me as per my research. So what's the way forward because issues of backfeed and inaccuracies will occur.
December 23, 20232 yr Author Thanks guys , I guess my next step is to move the CT onto a CAT/lan cable and see if that improves things
December 23, 20232 yr 48 minutes ago, Moffat said: @Scorp007 @Thunderdolt I keep worrying about this issue of location of CT coil and keep getting various schools of thought. It's not always possible to have inverter close to the DB, which seems to be @HenryJ's and my situation resulting in having to need a long CT coil cable. I've seen some installers put it at the input of the Inverter which seems to be wrong to me as per my research. So what's the way forward because issues of backfeed and inaccuracies will occur. This is a trail and error once you exceed the Std cable length. Cat4/6 cable is the 1st one can try. Just don't use 2 pairs thinking it's a thicker wire for the 2 wires. Stick to a twisted pair. If this fails you can still use the power meter when the distance can be quite far apart. Some houses there is a termination box on the side of the building where the munic cable joins with the consumer cable. The CT can also be used here if it is closer to the inverter. Yes the CT can never be at the inverter as it will not measure the current going to the non essential side. If however the whole installation is fed from the inverter essential like in cases with a 8kw or larger unit then it can be fitted at the inverter on the input AC feed. The concept is actually quite easy as you need to measure all the power coming/going to the grid point. Edited December 23, 20232 yr by Scorp007
December 23, 20232 yr 33 minutes ago, Scorp007 said: This is a trail and error once you exceed the Std cable length. Cat4/6 cable is the 1st one can try. Just don't use 2 pairs thinking it's a thicker wire for the 2 wires. Stick to a twisted pair. If this fails you can still use the power meter when the distance can be quite far apart. Some houses there is a termination box on the side of the building where the munic cable joins with the consumer cable. The CT can also be used here if it is closer to the inverter. Yes the CT can never be at the inverter as it will not measure the current going to the non essential side. If however the whole installation is fed from the inverter essential like in cases with a 8kw or larger unit then it can be fitted at the inverter on the input AC feed. The concept is actually quite easy as you need to measure all the power coming/going to the grid point. True, it is easy... but "some" installers always want to take the "mickey" and shortcuts. Sometimes they even bridge Essentials & Non-essentials at the DB and some end users are non-the-wiser, till there's issues.
December 23, 20232 yr Author Just some feedback, Solved it , albeit it temporary for now - move the CT Clamp to the municipal feed box and ran 15meters of 0.5mm speaker wire to the inverter and now everything is running perfectly thanks for the inputs
December 23, 20232 yr 1 hour ago, HenryJ said: Just some feedback, Solved it , albeit it temporary for now - move the CT Clamp to the municipal feed box and ran 15meters of 0.5mm speaker wire to the inverter and now everything is running perfectly thanks for the inputs Good to hear. Unscreened not twisted wire just tends to get interference.
December 23, 20232 yr Author Yeah thanks I have a CAT 7 I plan to replace it with when I have time to do it properly
December 24, 20232 yr 23 hours ago, Scorp007 said: Why? It can be on the cable between the munic and the DB at any point that is accessible or practical. You are absolutely correct! Maybe I should have said "Anywhere before the point of entry to the MCB." or words to that effect.
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