Hi all,

Been asking a few general questions on another thread, as have decided to move forward on a full blown Hager reinstall with new 54 Way (3 rows x 18)  Surface Mount DB Board. I have drawn up my current layout with horrific wiring which can be seen below. This is was a quick exercise with some assumptions as wires are running behind the backplate and I could not see all of them. I will follow up on another post in this thread with my thinking on my new proposed DB board layout with DIN SwitchOver etc.

Please can you assist with commenting on the following:

1. Current wiring, not sure how compliant it is, irrespective of getting a CoC when purchasing. Does something look out of order?
2. Additionally my DB Board is central in the house, where my PV Panels will be garage side and probably will have it's own new Mini DB as well. The cable run is about 30m 😞. I assume it is best to put the Inverters, MPPT, Battery etc. garage side and have it's own new Mini DB as well. I would probably need a 6 core cable running from the garage to the inhouse DB board carrying the grid supply (single phase) to the Inverter and back for my essential loads. Am I on the right track? Would you do it differently?

Thanks in advance.

Edited May 1, 20197 yr by d3nominat0r

Looking at the diagram, you're missing an earth leakage breaker on the main supply. Other than that I don't see anything amiss.

A separate distribution panel for solar is recommended. At least that's the way I have designed my system. Regarding the wiring, I would go with two separate 3 core cables instead of a single 6 core cable. To keep future upgrades in mind, you might also want to go with higher gauge wire.

In my case I am using a single phase inverter 3KW, but the wiring from the inverter to the distribution panel consists of two 3 phase wires (4 core 10mm2). So in future when I upgrade to a 3 phase inverter, I will not need to re-do the wiring.

 

 

@bluwater thanks, in my new design I will be adding a seperate earth leakage to each phase.  

A quick question, it is not clear for me in SANS 10142 whether I should be running a 4P Isolator and 4P Breaker for the 3-Phase supply to cater for neutral as well. Does anyone know? Will it hurt to do this? 

Also, I assume if I do a 2P Change Over Switch I should also have an independent Neutral bar from the other phases? Or does that not matter?

 

I did it with 4 pole breakers and a 4 pole changeover switch, it's been working fine. But then, I am only using 1 phase.

I also isolated all the load neutrals. So all the load that is on solar have live wires and neutral wires go into the solar distribution box. The live wires go into the breakers, the neutrals go to the bus bar. Then I used one 10mm2 wire to connect solar neutral bus bar with the main distribution box neutral bus bar.

@bluwater thanks, makes sense to me to isolate the neutrals when coming from different sources. I will need to share a neutral bus bar between the 3-phase supply to balance.

In my new installation, I am struggling to figure out what the best approach is considering the following:

• 3-Phase Supply from Council
• Generator 
• PV Installation with Battery Backup

Essentially, I would like to achieve the following (cost benefit should be positive, else I'll strike out a few of the ideas as it's a mind dump):

• Run essential loads of the PV during the day (if PV drops too low, fall back to the grid) (I would like to run the pool pump and electric geyser at different intervals from the PV installation as well depending on cost, else I will revert those to non-essential loads)
• Run essential loads of the Battery during the night (if battery drops too low, fall back to the grid)
• Run non-essential loads of the Grid (currently only planning to have the Aircons and Stove on this)
• Load-shedding during the day should not impact the above other than non-essentials should not powered
• Load-shedding during the night should not impact the above other than non-essentials should not powered
• In case of load shedding, always have the option to substitute the Eskom supply with the Generator
• Be able to charge the Batteries from the Supply (Grid or Generator) if PV is too low.

Balancing the 3-Phase Supply seems problematic as this solution seems 80% of the grid, is this an issue?

Any thoughts on the above?

Edited May 3, 20197 yr by d3nominat0r

I have no experience with generators and how to integrate them with solar. I think a good way to start is to begin with a layout diagram with all the wiring connections and get other member's opinion on it. That's the way I began.

Regarding running load off the batteries during the night. I would not recommend it. It might seem like the logical thing to do, but from a cost benefit analysis, you are better off using the grid, it's cheaper than batteries. So 1st priority is solar, 2nd is grid 3rd is battery and 4th is generator.

 

So here is my thinking for a proposed DB Board layout (in the scullery), Sub DB Board for Inverter will be in the Garage with all the PV kit and batteries.

Hope this make sense for everyone, in summary this is my thinking.

Phase 1: Dedicated to the essential loads, can be switched out with a generator supply if needed for Inverter if batteries are running low
Phase 2: Dedicated to Sub-DB for Spa (Pumps x 2, Blower, Spa Heater) and Aircons
Phase 3: Dedicated to Stove and perhaps Pool + Geyser (Not sure if it's better to leave on Phase 1?, in hindsight perhaps better leaving on Phase 1 and figuring out how to switch in front or behind inverter).

As for the comment around running load off batteries overnight, I'm considering getting a 5KVA Lithium Battery, however this is probably something to be setup on the Inverter and should not impact my DB Board design? @plonkster @The Terrible Triplett, would appreciate your views on this please.

Edited May 3, 20197 yr by d3nominat0r

I've made a minor update, forgot to include the Inverter Wiring flows.

Edited May 3, 20197 yr by d3nominat0r

@d3nominat0r thank for the vote of confidence but I'm nowhere qualified to give any opinion. 🙂 

In my innocence I do have two questions If I read the driagram right:
So you want the gennie to feed either the inverter OR the essential circuits?
Is that changeover of the gennie not supposed to be between the gennie and the main DB?

From what I learnt gennies must be completely separate from the grid. It can feed the inverter during a power failure, but that is a manual choice, no?

You got the general idea right, now just get a sparky to execute it properly 🙂

8 minutes ago, plonkster said:

You got the general idea right, now just get a sparky to execute it properly 🙂

Appreciated the feedback, just a general question regarding the Victron MultiPlus vs. the new GoodWe Hybrid Inverters. Not that it impacts my DB Board Design, but just a clarification for my benefit.

• The Victron Units Run either in Grid Passthrough, PV or Battery mode, but cannot supplement the PV with Grid Power if needed (Yes/No)
• The GoodWe Hybrid Units can be setup to supplement the PV with Grid Power if needed (Yes/No)

Is Hybrid Inverters approved to be used by council?

Edited May 3, 20197 yr by d3nominat0r

1 minute ago, d3nominat0r said:

The Victron Units Run either in Grid Passthrough, PV or Battery mode, but cannot supplement the PV with Grid Power if needed (Yes/No)

Victron units can "mix" power, ie supplement with the grid. But it has to be configured as an ESS system, which requires extra configuration on the inverter, and a venus device (ie a color-control or a Venus-GX).

The Goodwe comes out of the box as a Hybrid.

17 minutes ago, plonkster said:

Victron units can "mix" power, ie supplement with the grid. But it has to be configured as an ESS system, which requires extra configuration on the inverter, and a venus device (ie a color-control or a Venus-GX).

The Goodwe comes out of the box as a Hybrid.

Thanks got it. Since my Sub-DB and Inverter is 30m away from my DB board, I will be running two 3-core cable between my Main-DB (scullery) and Sub-DB (garage). Is there any specific components that should go into the Main-DB? Based on what I have seen, everything should be able to go into the Sub-DB. The 3-core cable is going into the Sub-DB/Inverter and then the inverter output is going back to the Main-DB via another 3-core cable. I'll put another Earth Leakage on the Sub-DB before going into the Inverter for protection. Does this make sense?

I also see some people have islanding devices? Why are they needed?

Edited May 3, 20197 yr by d3nominat0r

17 minutes ago, d3nominat0r said:

Is there any specific components that should go into the Main-DB?

If there is an energy sensor/meter involved, such as in a Victron system you might have a Carlo Gavazzi modbus meter used for grid-limiting, that would go in the main DB, right before the branch-off that goes to the sub-DB where your inverter is connected.

18 minutes ago, d3nominat0r said:

I also see some people have islanding devices? Why are they needed?

You might be thinking of an old photo of mine. I installed that with my previous Multi to make it NRS097-2-1 compliant (because the Multi didn't comply on its own). I ended up replacing the inverter with one that doesn't require external anti-islanding (and Cape Town would not accept the combo anyway), so it is no longer in there. Not required.

6 hours ago, plonkster said:

If there is an energy sensor/meter involved, such as in a Victron system you might have a Carlo Gavazzi modbus meter used for grid-limiting, that would go in the main DB, right before the branch-off that goes to the sub-DB where your inverter is connected.

@plonkster, thanks. Just to check my understanding, the CG is used to block any feedback back to the grid? Have one of those prepaid meters that dislike feedback.

Due the distance from my Main-DB to Sub-DB (30m), I assume it would be installed at the Sub-DB as it needs to be connected to the Venus Colour GX?

 

Edited May 3, 20197 yr by d3nominat0r

Sorry, also if my essential loads are connected to AC out on the Victron Multiplus is this meter still required?

14 hours ago, d3nominat0r said:

Due the distance from my Main-DB to Sub-DB (30m), I assume it would be installed at the Sub-DB as it needs to be connected to the Venus Colour GX?

You install it at the point where you want the inverter to achieve the zero point. What a Victron ESS system does is to power both the loads on the output AND feed some extra power out of the input to cancel out any loads you may have on that side (non-essential loads). So it also saves you money on the loads that are not backed-up, that is the idea.

In order to do this, it has to know how much to feed back, so it needs a zero-point, a place where a meter is installed that it attempts to zero. It basically increases power until this meter is close to zero. So this meter has to be installed where you want the zero-point to be, which is usually immediately after the prepaid meter, in other words, in the main DB for most people.

If that is 30 meters away, you're going to use a 30 meter communication cable to connect it to the Venus-GX. No worries about the distance... I had a customer who put this 200 meters away and it still worked (though it is technically out of spec).

If you don't want to feed power to the non-essential loads, then you don't need this meter.

Edited May 4, 20197 yr by plonkster

On 2019/05/03 at 5:46 PM, d3nominat0r said:

I will be adding a separate earth leakage to each phase.

Do you have no actual three-phase loads then? Imagine a perfectly balanced three-phase motor. Plenty of line current, no neutral current. The single phase "earth leakage" (which is actually looking for balanced line and neutral currents) will see way more than 30 mA difference and trip.

A lot of EV chargers are three phase these days, so you may want to plan for one of those in the future.

Three phase residual current breakers add the currents in all three phases, plus neutral.

3 hours ago, plonkster said:

You install it at the point where you want the inverter to achieve the zero point. What a Victron ESS system does is to power both the loads on the output AND feed some extra power out of the input to cancel out any loads you may have on that side (non-essential loads). So it also saves you money on the loads that are not backed-up, that is the idea.

In order to do this, it has to know how much to feed back, so it needs a zero-point, a place where a meter is installed that it attempts to zero. It basically increases power until this meter is close to zero. So this meter has to be installed where you want the zero-point to be, which is usually immediately after the prepaid meter, in other words, in the main DB for most people.

If that is 30 meters away, you're going to use a 30 meter communication cable to connect it to the Venus-GX. No worries about the distance... I had a customer who put this 200 meters away and it still worked (though it is technically out of spec).

If you don't want to feed power to the non-essential loads, then you don't need this meter.

@plonkster thanks, this make perfect sense. Really appreciate the feedback. As for the comms cable, I have read that you can use CAT5e network cable with RJ45 connectors to achieve this?

2 hours ago, Coulomb said:

Do you have no actual three-phase loads then? Imagine a perfectly balanced three-phase motor. Plenty of line current, no neutral current. The single phase "earth leakage" (which is actually looking for balanced line and neutral currents) will see way more than 30 mA difference and trip.

A lot of EV chargers are three phase these days, so you may want to plan for one of those in the future.

Three phase residual current breakers add the currents in all three phases, plus neutral.

There is no three-phase loads in the house I bought. It is biggish house at 500 m2 and as such a single-phase 63A was insufficient for the loads in the old days. Each phase was treated as a separate 63A supply to spread and balance the loads. 

But as things stand now, I actually have limited use for the three-phase supply and can easily get away with a single 63A supply. However, the municipality do not want to convert back to single-phase supply. I therefore still need to try and balance the three-phases as much as possible, but it turns out very difficult to do with low loads.

It also seem cheaper to have 3 x Victron Multiplus II units than a three-phase Victron, but I cannot see the use.

Edited May 4, 20197 yr by d3nominat0r

9 hours ago, d3nominat0r said:

CAT5e network

The meters use modbus-rtu at 9600 baud rate. That is fairly slow and works well on most shielded-pair type cabling. On longer runs you want to terminate it at the end. So yeah, cat5 should work fine.

10 hours ago, d3nominat0r said:

I therefore still need to try and balance the three-phases as much as possible, but it turns out very difficult... 

Is there a financial penalty for unbalanced loads? If they let you go to a single phase supply, it would be completely unbalanced anyway. If no penalty, why not ignore two phases? Or do whatever is convenient for you? I assume that loads will roughly balance as they usually tend to. 

6 hours ago, Coulomb said:

Is there a financial penalty for unbalanced loads? If they let you go to a single phase supply, it would be completely unbalanced anyway. If no penalty, why not ignore two phases? Or do whatever is convenient for you? I assume that loads will roughly balance as they usually tend to. 

Interesting question, would this negatively impact metering/cost by only using one phase? Effectively the three phase installation will be totally unbalanced with two phases not in use. Does it matter?

Normal residential 3-phase electricity meters will correctly record total power usage even if you only use power on a single phase. It is recommended to divide the circuits/loads across the 3 phases so that there would be roughly the same load on each phase if all circuits/loads were in use, but in practice one never uses all loads at the same time.

I have a 3-phase supply but many of the houses in our street have a single phase supply. It looks like they try and balance things out by connecting houses, with single-phase supplies, roughly evenly across the phases.  We have had a couple of occasions where one phase has been down and only a few houses in the street were affected.

I have also installed my system on a single phase and have not run into any issues.

EDIT: The municipality generally wants the maximum possible current drawn on each phase to be roughly equal. It does not matter if you are currently using a relatively low un-balanced current.

Edited May 5, 20197 yr by NigelL

@NigelL Thanks, makes a lot of sense and would simplify my installation considerable and reduce cost. Going to have a stab at putting everything on a single phase, calculating the load. I get the added benefit as mentioned with the the CG Meter to feed back to the non-essential loads if there is access PV during the day which would result in more cost saving.

Edited May 6, 20197 yr by d3nominat0r