June 27, 20233 yr Hi Guys Why does a 8.8kw Deye inverter give 115v on live and 115v on neutral when in off-grid mode?
June 27, 20233 yr Author In off-grid mode, there is no incoming earth, neutral or live, so what must be bonded?
June 27, 20233 yr If you are fully off grid you can hard bond the earth and neutral at the inverters UPS terminal with a small piece of wire.
June 28, 20233 yr Author Should we do the hard bond, we will then be pushing 110v unto the earthing throughout??
July 21, 20233 yr What you have is known as a floating earth, which can cause a lot of strange problems, susch as getting shocked by the water in your taps. I also had that issue, and solved it by having an Earth Spike installed (10 metres from any bulding) and have a 16mm Earth copper cable run directly to the inverters external earting terminal (lower right side). Another thing to double check is that there is no possible problem being caused by the reversal of the live and neutral feed going to the DB board from the inverter. Under normal circumstances, the Neutral and Ground should be almost the same voltage with referrence to the live feed. This is what result from a municipal Earth-Neutral common feed. You need to make your own Earth-Neutral bond.
July 22, 20233 yr On 2023/06/27 at 1:49 PM, FrankcF said: Hi Guys Why does a 8.8kw Deye inverter give 115v on live and 115v on neutral when in off-grid mode? Good day @FrankcF let's see if i can explain in laymans terms the problem you are experiencing. You have what is called "floating neutral" due to the fact that you don’t have an earth reference from earth to the inverter(no incoming earth wire). You need to establish what we call a TN-C earthing system. The way to do this is firstly to install an earth spike in the ground shortest distance to your db board or inverter. Then you need to use 16mm² earth conductor( green/yellow wire) from the earth spike to the main earth bar in your db.Then from the inverter output terminals live to your Main breaker, neutral from inverter to neutral bar in db and earth from inverter to earth bar in the db. You now need to put a permanent wire across neutral and earth on the inverter output. If you now switch the inverter on it will be in islanding mode as you have no incoming power feed, measure between neutral and earth in your db and you need to get as close to 0v as possible but any voltage reading above 20v ac is an indication that you don’t have a good earth refrence from your earth spike.If you get any voltage above 50 volts ac between neutral and earth then switch the inverter off and install a second earth spike. There are ways to measure the resistance but you need specialized testers to do this( earth loop impedance or fall of potential method) If a good earth refrence is not obtained your protection devices in the db board will not function correctly( long tripping times or not tripping when fault currents occurs) and is dangerous. Hope you have a better understanding and will be able to sort it out. Edited July 22, 20233 yr by TaliaB
July 22, 20233 yr On 2023/06/27 at 5:17 PM, Nexuss said: If you are fully off grid you can hard bond the earth and neutral at the inverters UPS terminal with a small piece of wire. Just bear in mind that the inverter will rejet AC input of a portable generator with hard N-E bond in place....
July 24, 20233 yr On 2023/07/22 at 1:27 PM, Kilowatt Power said: Just bear in mind that the inverter will rejet AC input of a portable generator with hard N-E bond in place.... Yup, 100% correct, I had that problem when I was trying to get my generator to connect to my inverter as I had a hard bond in place on the generator
July 27, 20233 yr On 2023/07/24 at 10:41 PM, Sc00bs said: Yup, 100% correct, I had that problem when I was trying to get my generator to connect to my inverter as I had a hard bond in place on the generator @Sc00bs @Kilowatt PowerWhile we are on the topic of generators and it is my last day of leave before flying to JHB i have time to discuss and explain "portable generators" the safety aspects and the reason some generators not accepted by inverters as input power. In South Africa we have this wonderful part of our lives that occurs at a near daily basis, called load shedding. In the current state of things people are running to buy which ever and what ever generator they can and often times these people have no idea of what exactly they are purchasing. Most people purchase your average little Honda/Chinese/etc 2.5 – 5.5 kVA generators and a percentage of these people would want these things wired permanently to their homes/businesses. There are a few problems with using these generators as permanent on site generators supplying equipment and house holds. The first problem that we must get through is a simple matter of design, these generators are designed to supply appliances and specific equipment , not really households and all the required safety devices, most of these generators are of the center tap type meaning that they have 1 secondary winding split into two by means of a center tap, this generates a ‘two phase supply’ in most cases on your connection considered to be live you will get a voltage of around 150 Volts and on the connection considered neutral you should measure around 70 volts, which makes up your 220 Volts. This brings us to problem number two in this discussion, being the safety, with these generators connected to your house your earth leakage will not work and you will experience nuisance tripping, this just increases the risk of electrocution. The other safety problem that arises is that of earthing, you cant effectively earth your alternator on your generator, and because of this the potential to earth is far greater and causes more danger in respects to earth fault. This poses great danger for human beings and animals who come into contact with this installation because an unearthed system creates the possibility of you becoming the Earth continuity conductor and being electrocuted. These two problems collate and are part of the reason we find the following in SANS 10124:1 regulation 7.12.2.7 ‘7.12.2.7 A 230 V generator with a V-O-V earth connection (centre tap on winding which is earthed), shall not be connected to a fixed electrical installation. Amdt 6 NOTE Such a generator may be used as a free-standing unit to provide power to specific appliances. Amdt 6′ The solution to this problem is a bit out of the ordinary, but quite simple, ask your electrician to remove your center tap and isolate it, there after you earth the neutral side of your winding and potentiality create a TN-C-S system on your generator, which is legal. and therefore you can now comfortably issue a COC for the installation. Lastly electricity, like firearms has a very, very long history of deaths following it. So safety is the number one priority. Edited July 27, 20233 yr by TaliaB
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