Pretty close to it yes
In your diagram you only need a Sub Main Switch (Double pole breaker) or a Isolator. Both aren't needed. You can do both if you feel so inclined
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Axpert invertors
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In your diagram you only need a Sub Main Switch (Double pole breaker) or a Isolator. Both aren't needed. You can do both if you feel so inclined
Pretty close to it yes
In your diagram you only need a Sub Main Switch (Double pole breaker) or a Isolator. Both aren't needed. You can do both if you feel so inclined
The reasoning behind both is that you have to have a sub main on the additional DB where it is not next to/close by the existing DB. The sub main then feeds the changeover switch in case you need to bypass the inverter when it fails or for other reasons. The isolator is feeding the inverter and if the inverter is bypassed by means of the changeover switch you "isolate" the inverter's input to work on it or remove it, while power is still connected to the changeover switch. Having both you can isolate and work on the inverter while the "inverter circuits" are still powered via the changeover switch - long explanation - hope that it makes sense.
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If this is the correct block diagram for my inverter then my testing will prove the following.
- When the inverter is in bypass mode the double poll safety relay will be closed. This means that the Inverter AC output live and neutral are coming directly from mains. This means it is now currently bonded to the mains.
- However when the inverter is running on batteries the safety relay will be open thus the live and neutral from the mains are completely isolated from the inverter AC output. This is why the the neutral to earth on the inverter AC output shows a floating voltage. That means on battery power there is no neutral to earth bond at all.
- Taking into consideration that my lights and selected plugs will always be off grid and will always be isolated from the mains it implies that there is no bonding that can clash with the mains bonding. So in this situation bonding the AC inverter output neutral / earth makes sense.
- From the block diagram from what i can see you do not need or require a bonding relay and can bond the neutral to earth in the inverter DB panel.
- At the same time it would be wise to add an EL in the inverter DB panel for the plug circuits. Remember that I have moved my lights and selected plug breakers to the inverter DB Panel so they are completely isolated from the main DB panel.
Yes, if you have a (re-branded) Axpert 4KVA or 5KVA inverter.
Correct
Correct
Correct
Yes, no need for a “bonding” relay if the inverter will always be off-grid. Yes, do the N-E bond permanently.
Yes, an EL unit would be required, unless you run the inverter output to dedicated plug outlets.
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I have put one in just for safety sake. Thanks superdiy
greg_SA
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So are you only going to use solar to charge your batteries? And you won't have any connection to your inverters 220V input?
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No. There will still be a connection to the inverter AC input from mains. The reason for this is if the batteries are low and it is night time the MPPT built in charger will charge the batteries.
Also remember that if your load is to high for the batteries to run it it will also go into bypass mode so you do need the AC input to your inverter.
The Axpert is quite an intelligent inverter. Here are some scenarios,
Day time
1) if your batteries are to low to power the isolated items eg lights and dedicated plugs it will draw power from the solar panels at the same time to make up the difference or depending how you configure the inverter the panels will charge the batteries whilst supplying power in bypass mode from the mains.
2) If your batteries are fully charged it will supply power directly from your pv panels if the load is not greater than the output of the panels. If the panels cannot maintain the load it will take what it requires from the charged batteries to compensate.
3) If there is not enough sun power to your pv panels and your batteries are not strong enough to handle the load the inverter will go into bypass and supply the inverter AC output from the mains whilst also charging the batteries from mains.
Night time
1) If your batteries are not charged enough it will supply power from the mains.
2) if they are charged enough and can handle the load then the inverter will use the batteries power.
These are different configurations you can setup on your Axpert inverter through the LCD panel
OK, but then your inverter is not off-grid and you cannot permanently connect the N & E and you will need the "bonding" relay.
greg_SA
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Exactly. In bypass mode, you'll have two neutral-earth bonds. So between them, you'll have neutral currents flowing in the earth conductor.
Yes, but in all these cases Eskom is always on, so a simple Eskom-powered relay would always be powered, so neutral and earth would never be connected.
The bonding relay needs to follow the internal bypass relay, which (if you have solar panels) depends on more than just if Eskom is present or not
The bonding relay needs to follow the internal bypass relay, which (if you have solar panels) depends on more than just if Eskom is present or not
Yes, but when the house is running off solar power the plugs won't be on that circuit
Yep, have to agree here. If you are doing the neutral/ground relay we proposed in the thread. We are assuming that your are using your Axpert Output source priority setting to Utl
Which is Utility first
SOL and SbU should not use this approach.
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Yes, makes sense. If Eskom is available, but inverter makes use of PV input to drive the load, the "Safety Relay" will disconnect the inverter input from Eskom and effectively break the N-E bond before the main E/L unit and in this case the N-E bond needs to be created at the inverter output. Back to the drawing board...
I am very curious to know what all the "pro" installers of these Axpert inverters are doing and if they actually do legal and safe installations or just assume that their installations are legal and safe...
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There is a better solution, namely using the 12v supply of the Inverter relay. That will work for all situations but requires modification which voids your warranty.
We were working on a solution here that does not involve anything too technical, doesn't void the warranty and works for most people in SA. Since most of us are using it as a UPS I think that is a decent solution
We were working on a solution here that does not involve anything too technical, doesn't void the warranty and works for most people in SA. Since most of us are using it as a UPS I think that is a decent solution
No visible leds when on inverter power ?
Bit of an complicated option
Sense current on output
If output more than input bond neutral/earth
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By "We were working on a solution here", do you refer to this thread? I'm still stuck because I have an infini, which is a true hybrid, and I have PV panels installed as well. The infini combines PV power and Eskom to supply the load, no simple relay which switches between PV and Eskom to which I can connect a "bonding" relay.
I have two lamps, one connected to Eskom, another connected to my alternate power.
Eskom power out and alternate power showing power = Inverter power.
If you want more than these, why not get this: http://www.comx-computers.co.za/RCT-AXPERT-CONTROL-PANEL-RCT-Remote-Display-For-The-Buy-p-126057.php
The relay option?
not following here tbhYep, you don't see it that way?
To be fair, this thread is titled Axpert inverterI'm still stuck because I have an infini, which is a true hybrid, and I have PV panels installed as well. The infini combines PV power and Eskom to supply the load, no simple relay which switches between PV and Eskom to which I can connect a "bonding" relay.
Doesn't the infini require constant power from Eskom tho?
I just thought maybe "you and your colleagues at work" perhaps are working on a solution.
Point taken.To be fair, this thread is titled Axpert inverter
I was looking for a general solution.constant power? Please explain. It works similar to the Axperts, but where the Axpert is not a true hybrid, the infini is. The infini can also grid-tie.
What I meant was if axpert have a visible led when on inverter you can use optic sensor to activate earth bond on output .
Let me try again
Add current transformer on input (A)
Add current transformer on output (B)
Of current B is greater than A
Load must run off inverter connect the neutral earth bond