Help with wiring diagram from Solis

[Do It Yourself]

Hi Everyone,

I have a Solis RHI hybrid inverter and I'm using this diagram to wire it.



I will be wiring it very similar to this diagram but I'm having trouble wrapping my head around the consumer unit section.



Where I've circled in blue here, would that part be a henley block?


and then where I've circled in red, would that be a switch like this one? (this one is 63a)

Finally, I struggle to see how the critical loads will have power on a normal day to day basis when the switch is set to inverter, because the AC OUTPUT that connects the critical loads only comes into play when EPS is activated?

Thanks for your help!

 

[Joeyhza]

The output on the AC Backup operates in bypass essentially when grid is available. EPS is activated on grid failure and of course a battery connection.
As long as the grid is up though the essential loads are getting power from Mains.

The red circle is a transfer switch to power those critical loads directly from grid in the event of an inverter failure. So, yes, the isolator switch would work. Not sure as to your country codes if that specific device would meet the requirement but the device you attached does serve the function of a transfer switch.

The blue circle indicates that the AC Input for the inverter needs to be wired from the main consumer unit before the Earth Leakage/RCD. Also not sure what code dictates in your country but the way I have it is its wired to another properly rated circuit breaker in my main consumer unit.

 

[Do It Yourself]

The output on the AC Backup operates in bypass essentially when grid is available. EPS is activated on grid failure and of course a battery connection.
As long as the grid is up though the essential loads are getting power from Mains.

The red circle is a transfer switch to power those critical loads directly from grid in the event of an inverter failure. So, yes, the isolator switch would work. Not sure as to your country codes if that specific device would meet the requirement but the device you attached does serve the function of a transfer switch.

The blue circle indicates that the AC Input for the inverter needs to be wired from the main consumer unit before the Earth Leakage/RCD. Also not sure what code dictates in your country but the way I have it is its wired to another properly rated circuit breaker in my main consumer unit.

So if AC Backup is normally bypassed when grid is up, how are the critical loads connected to grid in this case? As the switch (red circle) would be set to inverter under nomral operation and I can't see any other grid connection on that wiring diagram that would feed the critical loads?

 

[Do It Yourself]

Or are the critical circults split, with an RCD for them in both the main CU and the Solar CU?

 

[Do It Yourself]

This is me in the process of wiring it, but I've a feeling it's wrong. Particularly the part where AC Backup comes in, because it won't be isolated from the grid.

 

[Joeyhza]

Something definitely looks wrong. It's all a bit convoluted for me to pinpoint exactly what looks wrong though

Did you perhaps already flip the switch on it all? Any smoke, explosions or fire?

 

[1234enough]

The blue circled section is what I would say is within a normal split load consumer unit(see attached image), grid power comes in - main 100a switch - splits to the individual circuits ( non rcd protected circuits + via two or more rcd's then onto Mcb's).
Red circled switch is to allow critical loads to be fed from either the inverter or grid.
I am using a 4 pole rotary isolator to combine the function of the as labelled "ac input" + "ac output" as one switch and another rotary switch for the red circled. This allows the inverter to be fully isolated & bypassed with two rotary switches. Note I have no idea in regards compliance with regs.

 

[1234enough]

If I was you, I'd make things safe. STOP, sit down with pencil and paper and draw out what you need to achieve.
I was always taught measure twice and cut once, sometimes the more we try the worse it gets, think we have all been there -- pull cable in to where we know(or think we know) it needs to be, cut it , then realise oh bugger.

 

[Do It Yourself]

It's been working for a couple of weeks (even when I posted that messy annotation photo above it was working).

Where I was stuck was the exact wiring for the AC Backup coming from the solis inverter as my batteries are arriving soon so prepping for that.

I am using a 4 pole rotary isolator to combine the function of the as labelled "ac input" + "ac output" as one switch and another rotary switch for the red circled. This allows the inverter to be fully isolated & bypassed with two rotary

That's interesting, I might try that.

My DNO is coming tomorrow to install an isolator switch at the front of the house which will allow me to move my main tails from out of my main CU, and into the henley block, and then I think I'll be all set - minus the rotary switch you mention above. ?

Once the batteries come I can test the EPS.

 

[Do It Yourself]

The output on the AC Backup operates in bypass essentially when grid is available. EPS is activated on grid failure and of course a battery connection.
As long as the grid is up though the essential loads are getting power from Mains.

I'm still confused with these solis diagrams ?, so I've read back over what you said here and this is where I'm confused and I'm sure it's just my limited understanding of electrical wiring. But you said 'As long as the grid is up though the essential loads are getting power from Mains.'

But in the installation diagrams.. there are no connections to mains power for the critical loads!?



so if I look at the other wiring diagram from my first post, there IS a connection to mains going to the critical load RCD but it's behind a switch that would in normal circumstances be set to Inverter..




Where am I going so wrong with this? ?

 

[John Frum]

The blue circled section is what I would say is within a normal split load consumer unit(see attached image), grid power comes in - main 100a switch - splits to the individual circuits ( non rcd protected circuits + via two or more rcd's then onto Mcb's).
Red circled switch is to allow critical loads to be fed from either the inverter or grid.
I am using a 4 pole rotary isolator to combine the function of the as labelled "ac input" + "ac output" as one switch and another rotary switch for the red circled. This allows the inverter to be fully isolated & bypassed with two rotary View attachment 112780switches. Note I have no idea in regards compliance with regs.

Cool.
If I'm interpreting this drawing correctly there is no neutral ground bond so no passive ground fault clearance.
The system relies on the residual current devices to trip on current mismatch between hot and neutral.
The branch circuits are bonded to the planet for equi-potential.
I expect the transformer is also grounded but the return path is high impedance.

If one trusts the RCD its a nice simple system.
I wish they had drawn the hots from the main breaker with a busbar as they did with the neutral.

 

[1234enough]

I'm still confused with these solis diagrams ?, so I've read back over what you said here and this is where I'm confused and I'm sure it's just my limited understanding of electrical wiring. But you said 'As long as the grid is up though the essential loads are getting power from Mains.'

But in the installation diagrams.. there are no connections to mains power for the critical loads!?

View attachment 112998

so if I look at the other wiring diagram from my first post, there IS a connection to mains going to the critical load RCD but it's behind a switch that would in normal circumstances be set to Inverter..


View attachment 113005

Where am I going so wrong with this? ?

The pink circled switch i believe is a changeover switch, only to be used if you need to bypass the inverter - in event of inverter fault.
Generally if PV or battery power is not available or exceeds load requirements the inverter allows power to flow through from grid to loads.
Don't know anything about your inverter specs, but if inverter has an islanding feature , in event of grid failure the "critical loads" will still be powered from inverter by isolating itself from the grid and providing power (subject to suitable power being available - battery / PV ect). Critical loads should be suitable for power the inverter can supply.

 

[Do It Yourself]

The pink circled switch i believe is a changeover switch, only to be used if you need to bypass the inverter - in event of inverter fault.
Generally if PV or battery power is not available or exceeds load requirements the inverter allows power to flow through from grid to loads.
Don't know anything about your inverter specs, but if inverter has an islanding feature , in event of grid failure the "critical loads" will still be powered from inverter by isolating itself from the grid and providing power (subject to suitable power being available - battery / PV ect). Critical loads should be suitable for power the inverter can supply.

Thanks, I am aware of all this. This solis inverter is capable of island mode. My question is still unanswered though.

How and where on these diagrams are the critical loads connected to grid power under normal operation?

If the grid connection is just implied, and not drawn on the diagram, then I see that as an issue. Because when grid power stops for any number of reasons, how can we be sure we have isolated the critical loads (now being powered from battery) from the grid automatically?

I've found a solution in my setup using a contactor, which will isolate the critical loads from the grid automatically when grid goes down. But I don't think my workaround is the official way, so I'm curious as to how others have done it.

 

[1234enough]

Under normal operation grid power pass's through the inverter to which ever loads are connected to said inverter.
If inverter can supplement or sustain this load by using PV or battery it will.
Critical loads is simply the circuit which will self island if grid fails.

 

[1234enough]

This is the self islanding isolator in victron inverter.
You talk as your inverter has similar? If it has you don't need a seperate isolator.

 

[1234enough]

Ps AC1 out is critical load and AC2 out is non critical load.
In the event of grid failure AC1 is self island circuit and powered from inverter and AC2 is off.
That's my understanding.

 

[Do It Yourself]

Under normal operation grid power pass's through the inverter to which ever loads are connected to said inverter.
If inverter can supplement or sustain this load by using PV or battery it will.
Critical loads is simply the circuit which will self island if grid fails.

Thanks for this, the wiring diagram for the Victron inverter you showed makes sense, you can see how ACout1 becomes isolated from the grid.

Unfortunately it's not clear on the solis diagram how that works, and I've yet to figure it out - but I think we're getting somewhere!

 

[1234enough]

This is extract from my schematics for isolator / bypass of inverter, 2x rotary isolator ( 32a one is only 4 pole cos it was same price as 2 pole one).
L1 fed from grid / main 100a / ET112 (victron energy meter) / 40a MCB, supply to critical loads 32a RCD.
Note - unknown if compliant with regs, but seems safe to me ?

 

[1234enough]

Ps live to ET112 should be in/out and not as drawn?

 

[Welly]

Hi Everyone,

I have a Solis RHI hybrid inverter and I'm using this diagram to wire it.

View attachment 111403

I will be wiring it very similar to this diagram but I'm having trouble wrapping my head around the consumer unit section.

View attachment 111405

Where I've circled in blue here, would that part be a henley block?

View attachment 111406
and then where I've circled in red, would that be a switch like this one? (this one is 63a)
View attachment 111407
Finally, I struggle to see how the critical loads will have power on a normal day to day basis when the switch is set to inverter, because the AC OUTPUT that connects the critical loads only comes into play when EPS is activated?

Thanks for your help!

This video may shed some light:

around 33 minutes the backup function is discussed... but I found the whole video interesting. It's the explanation for the Italian system around 37 minutes that is the equivalent of your proposed system, but it incidentally explains the "normal" UK system that's inside the Hybrid inverter...