February 10, 20233 yr Hi folks. I'm hoping someone can clarify something for me. I'm just about ready to start wiring up a sub DB board for a Sunsynk 5kva inverter & battery backup combo. I've heard conflicting information from different sources regarding the use of single pole (phase and earth) and double pole (phase, neutral and earth) SPD's in terms of the correct format to use. Also, I understand that I need surge protection on the grid to inverter feed as well as the AC output of the inverter to essential loads. In a lot of the sub DB's I've seen I usually only see one SPD in either double pole or single pole format. Are you not meant to use a seperate SPD after your double pole MCB between grid to the inverter as well as a seperate SPD once again after your inverter AC out MCB to feed your essential circuits? Unless in these examples they're using an SPD after the main DB mains MCB feeding the inverter "In" MCB. If someone can clarify this for me I'd be grateful.
February 10, 20233 yr 11 minutes ago, Goof87 said: Hi folks. I'm hoping someone can clarify something for me. I'm just about ready to start wiring up a sub DB board for a Sunsynk 5kva inverter & battery backup combo. I've heard conflicting information from different sources regarding the use of single pole (phase and earth) and double pole (phase, neutral and earth) SPD's in terms of the correct format to use. Also, I understand that I need surge protection on the grid to inverter feed as well as the AC output of the inverter to essential loads. In a lot of the sub DB's I've seen I usually only see one SPD in either double pole or single pole format. Are you not meant to use a seperate SPD after your double pole MCB between grid to the inverter as well as a seperate SPD once again after your inverter AC out MCB to feed your essential circuits? Unless in these examples they're using an SPD after the main DB mains MCB feeding the inverter "In" MCB. If someone can clarify this for me I'd be grateful. My call will be either type in the AC in to the inverter. As a lay person I don't see the value on the AC out from the inverter as the inverter should not cause surges to your essential loads.
February 11, 20233 yr 15 hours ago, Goof87 said: If someone can clarify this for me I'd be grateful. First of all - how do SPD work? If a high overvoltage with respect to earth occurs, the protective element creates a short to earth and remains shorted. That should cause a preceding devise to trigger. The best would be the earth fault detection/breaker. The triggered SPD plug-in element must be removed and replaced. If you are connected to a fully underground distribution, the risk of a surge is very remote. I removed mine to make required space in the DB and handed it to a friend. Overhead high voltage lines have surge protectors in front of the transformers and at point of going underground. There is no point of a SPD after the inverter, as it cannot produce any surge.
February 18, 20233 yr I’m going to install surge protectors to the inverter do I need this on my appliances back into the house once eskom comes from their sleep mode. I also have a generator which hasn’t caused any issues to be appliances once I start it up…..just need one guidance sorry for hijacking this thread
February 18, 20233 yr 7 hours ago, Raiden2912 said: I’m going to install surge protectors to the inverter do I need this on my appliances back into the house once eskom comes from their sleep mode. If the appliances are backed up, then no. But you should consider surge protection for the non backed up circuits. Also lightning protection for each PV string. You got insurance? Some of them are introducing changes so that if you want to claim for damage to appliances you must have surge protection, in the DB (so ixnay on those plug in jobs) installed by a competent electrician. Also check settings on the inverter. Mine often doesn't connect to the grid immediately when the power is restored. It monitors the grid, but will only reconnect when voltage is stable and within range. So that gives extra protection to the inverter and to the backed up circuits. The problem i face is that the non backed up side will come back on when grid is restored, so I'm exposed there. This is the laundry 2nd geyser and pool pump. Edited February 19, 20233 yr by Bobster. Clarity
February 18, 20233 yr Thank you, something to consider. This forum has really enlighten me and I thank you for your advice and assistance! It’s truly appreciated
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