Axpert invertors

[savage]

Yep, agreed... The setup that Chris suggests makes the most sense.

It is just strange that the SANS diagrams show the UPS powered from an E/L. Hope that they don't insist on this for a COC.

It's not a requirement - especially not on bigger, permanently connected systems.

EDIT: SANS also just states that normal (i.e. white) plugs should be on Earth Leakage. There is also no requirement for dedicated (red) plugs to be on E/L

 

[savage]

BTW - Talking about SANS...

7.12.3.1.2: In an installation that is supplied from a combination of transformers and alternative supplies located near to each other, including an alternative supply (supplies), the neutral points of each of these items shall be connected to a single earthed neutral bar (see annex S). This earthed neutral bar shall be the only point at which the neutral of the installation is earthed. Any earth leakage device shall be positioned in such a way as to avoid incorrect operation due to the existence of any parallel neutral/earth path.

7.12.3.1.3: Where alternative supplies are installed remotely from the installation, or from one another, and where it is not possible to make use of a single neutral bar which is earthed, the neutral of each unit shall be earthed at the unit and these points shall be bonded to the consumer's earth terminal (see 6.12.4). The supply from each unit which supplies the installation or part of the installation, shall be switched by means of a switch that breaks all live conductors operating substantially together (see annex S), to disconnect the earthed neutral point from the installation

7.12.3.1.4: Where only part of an installation is switched to the alternative supply in the same distribution board, the neutral bar shall be split (see figures S.2 and S.3 in annex S).


I hope this sums it up nicely for those who are unsure. Neutral IS bonded to Earth, and double pole breakers MUST be used in order to DISCONNECT the Neutral/Earth, together with the Live wires.

Again, I'd be more than happy to share details (if required) as to why from the Transmission/Distribution side, Neutral is tied to Earth...

 

[savage]

Also worth noting for those with small / portable generators...

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

That will more than likely cover smaller Inverters as well, using a V-O-V center tap transformer for it's Earth generation (possibly Mecer units).

 

[Polv]

Kindly could you assist with the following:

My objective is primarily to reduce eskom costs and long term/secondary back up for outages and maybe even get off the grid.

I got my 5kva Axpert thanks to a friend and was hoping to start out with 12 x 250watt rensola panels (4strings) but don't want to batteries yet... As i just want to run on the solar preference and grid backup option... Ie cost saving during the day. I have now heard that i cant run the invertor without batteries, is that true?

Furthermore, since I am doing something now but with a long term view i wanted to hear if anyone has connected 2 x 5kva invertors and what the benefits and complications were

Ps will do the hard labour but will get an electrician to do the connections and assist on safety

 

[SilverNodashi]

Kindly could you assist with the following:

My objective is primarily to reduce eskom costs and long term/secondary back up for outages and maybe even get off the grid.

I got my 5kva Axpert thanks to a friend and was hoping to start out with 12 x 250watt rensola panels (4strings) but don't want to batteries yet... As i just want to run on the solar preference and grid backup option... Ie cost saving during the day. I have now heard that i cant run the invertor without batteries, is that true?

Furthermore, since I am doing something now but with a long term view i wanted to hear if anyone has connected 2 x 5kva invertors and what the benefits and complications were

Ps will do the hard labour but will get an electrician to do the connections and assist on safety

I don't think you can run the Axpert with only the panels connected to it. From what I understand you need the batteries as well.

 

[savage]

I got my 5kva Axpert thanks to a friend and was hoping to start out with 12 x 250watt rensola panels (4strings) but don't want to batteries yet... As i just want to run on the solar preference and grid backup option... Ie cost saving during the day. I have now heard that i cant run the invertor without batteries, is that true?

I haven't attempted to run it without batteries - but I am relatively sure that it won't run without at least A battery. Easiest would be to just get 4 x 12V/10Ah batteries in series or something like that (basically, smallest / cheapest crap you can find). Seeing that you won't YET depend on the batteries for load shedding, putting in something cheap/small more than likely will keep the inverter happy, whilst you also don't need to throw too much money away in the process (these batteries will die, very quickly).

Secondly, for what you want - the Axpert won't be your best choice. As the Axpert does not sync with the grid, it has two basic modes of operation (when there is power (supply) at least)...

1 - It either runs in bypass, pulling power only from the supply directly (i.e. your load runs entirely from Eskom), or
2 - It either runs from PV, pulling power only from PV

If your load is for example 2kW, and you can only manage 1.8kW from PV, it will disconnect your PV, and power the load from Eskom. Not a lot of people are aware of this (I wasn't initially either), and I am actually replacing my Axpert with a bit more expensive InfiniSola which does grid tie (so the 0.2kW shortfall from this example will come from Eskom, whilst the remaining 1.8kW will come from my PV).

 

[Polv]

Thank you Guys very much for the help, will have a look at the InfiniSola.

Looking forward to read more of your threads

 

[newviper]

I haven't attempted to run it without batteries - .

Are you willing to try that please

 

[edmundp]

Savage is correct. The Axpert 5Kva does not run on panels only (I have one.) Thus IMHO - the Axpert is great if you either now or in future wish to go off grid and are diligent enough to be able to tweak your system to make full use of the energy provided ito battery capacity and solar performance.

The Infinisolars are for the guys wanting to save but not go off grid and do not want to constantly tweak a system to get the most bang for watt produced as it feeds back.

My only concern with the Infini's were the fact that I could only get hold of a 3 Kva one (but small) next was 10 Kva (too big) and they cannot be run in parallel.

 

[greg_SA]

It's not a requirement - especially not on bigger, permanently connected systems.

EDIT: SANS also just states that normal (i.e. white) plugs should be on Earth Leakage. There is also no requirement for dedicated (red) plugs to be on E/L

Hey Chris - Thanks for all the assistance and SANS references I now understand exactly what I should do. For my installation, it is a very simple change. I still find the SANS UPS drawings (S3) a bit odd, showing E/L on the input of the UPS, etc. But I suppose they can't have a drawing for every possible installation/piece of equipment.

 

[greg_SA]

I don't think you can run the Axpert with only the panels connected to it. From what I understand you need the batteries as well.

I powered my Axpert without batteries - it wasn't happy.

I think it says in the manual that you need batteries, but can remember exactly.

 

[savage]

Hey Chris - Thanks for all the assistance and SANS references I now understand exactly what I should do. For my installation, it is a very simple change. I still find the SANS UPS drawings (S3) a bit odd, showing E/L on the input of the UPS, etc. But I suppose they can't have a drawing for every possible installation/piece of equipment.

Don't worry - you're not the only one. It's obviously just an EXAMPLE - a very basic one at that. Their own drawing itself, isn't compliant with their regulations

 

[greg_SA]

My only concern with the Infini's were the fact that I could only get hold of a 3 Kva one (but small) next was 10 Kva (too big) and they cannot be run in parallel.

I read on some other forums that there is a 5kVA Infinisolar in testing phase, and should be available in the coming months... That post was back in February...

 

[JohnHay]

Hi Savage,

Does the double pole breaker count for your mains supply too? I had a look in my DB and the main only have a single pole breaker on live. Then it goes to the geyser and E/L, both of which are double pole.

Yes it is somewhere in the SANS doc and I'll find it at some stage.

 

[savage]

Hi Savage,

Does the double pole breaker count for your mains supply too? I had a look in my DB and the main only have a single pole breaker on live. Then it goes to the geyser and E/L, both of which are double pole.

Yes it is somewhere in the SANS doc and I'll find it at some stage.

It should be DBL Pole IMHO. A Earth Leakage can however 'act' as your main switch (i.e. serve both purposes). If your geyser is behind the E/L (which it should be), then your E/L will act as your 'main switch'.

A Geyser without E/L, isn't a good idea

 

[JohnHay]

It should be DBL Pole IMHO.

I also thought so... I bought the house before a COC was required as part of the sale.

A Earth Leakage can however 'act' as your main switch (i.e. serve both purposes). If your geyser is behind the E/L (which it should be), then your E/L will act as your 'main switch'.

But if you want to wire an inverter in, that will have to go before the E/L...

A Geyser without E/L, isn't a good idea

Why do you say so? My understanding was that fixed stuff like the stove and geyser did not need to be behind an E/L. They just need to be properly earthed? Your own picture in the "How to wire an inverter into my DB board" had the geyser and stove in front of the E/L? Or is just because of the itchy feeling you get when thinking of getting a shower?

 

[savage]

But if you want to wire an inverter in, that will have to go before the E/L...

Correct - which means in your case, you would need to upgrade your single pole 'mains' switch, to a double pole. Painful, as it would require Eskom / Council to temporarily switch off your electricity supply to replace the breaker.

Why do you say so? My understanding was that fixed stuff like the stove and geyser did not need to be behind an E/L. They just need to be properly earthed? Your own picture in the "How to wire an inverter into my DB board" had the geyser and stove in front of the E/L? Or is just because of the itchy feeling you get when thinking of getting a shower?

Sorry - I'm confused (10,000 things going on - my mind's wondering a bit)...

6.16.1.3 The power supply to every fixed appliance, except luminaires, shall be supplied through
a) a disconnecting device that disconnects both live conductors in a single-phase supply and all phase conductors in a multiphase supply, or Amdt 3
b) a socket-outlet that is directly accessible at all times that any person is exposed to such appliance while the supply is on. In the case of a remotely installed appliance, the position of the disconnecting device shall be indicated by means of a notice in close proximity to or on the appliance. Amdt 3


6.16.2 Water heaters
NOTE Water heaters include geysers, instantaneous water heaters including units for boiling water, and the like (see also 6.16.1). Amdt 4
6.16.2.1 All water heaters shall be bonded in accordance with 6.13.
6.16.2.2 Dedicated circuits shall be provided for water heaters and there may be more than one water heater on each circuit.
NOTE If a water heater is installed in a bathroom, see table 7.1 regarding earth leakage protection.


6.16.3.3 Stove connection
6.16.3.3.1 A stove designed to be a free-standing appliance rated above 16 A shall be connected through Amdt 4
a) a stove coupler which shall comply with SANS 60309-1/IEC 60309-1 and of dimensions as given in SANS 337 (a maximum of 45 A single-phase and 16 A per phase for three phase), or Amdt 5
NOTE 1 Earth leakage protection is not required for the stove circuit when a stove coupler is used.

Table 7.1 in regards to Geysers basically state that IF your geyser is located IN your Bathroom (Zone 1), E/L is required. Otherwise, you are correct, E/L not required. I do stand corrected here. If you have a stove < 16A, it should connect through a normal plug socket, which should already have E/L protection in any case.

Zone 1 is limited by
a) the vertical plane circumscribing the outer edge or 0,20 m from the inner edge (where the ledge is too wide) of the bathtub, shower basin, or for a shower without a basin, by the vertical plane 0,60 m from the shower rose, and
b) the horizontal plane 2,5 m above the bathtub or shower floor.

 

[DollyAAAA]

Ok, now I'm confused.

Do you have to put the feed from the inverter into a separate DB?

My understanding is that you may feed it back to your main board, provided it is marked as "alternative supply", has a double pole breaker and has visual and/or audible indication when there is power.

I have spoken to a few electricians, and the opinion is split on this. Some insist that you must have it in a separate DB.

I can't find anywhere in the SANS where this is stated explicitly.

Any thoughts?

 

[savage]

Ok, now I'm confused.

Do you have to put the feed from the inverter into a separate DB?

My understanding is that you may feed it back to your main board, provided it is marked as "alternative supply", has a double pole breaker and has visual and/or audible indication when there is power.

I have spoken to a few electricians, and the opinion is split on this. Some insist that you must have it in a separate DB.

I can't find anywhere in the SANS where this is stated explicitly.

Any thoughts?

Grey area - same story with downlights (esp. 12V downlights). There's no clear definition and most 'prefer' to have a separate DB in order to clearly separate it. There's also the likelihood that the existing DB can only accommodate one Neutral Bus Bar - thus, making it impossible to split the neutrals. In cases like this, you don't have a choice but to install a second DB.

Things like this really depends on a case by case basis. This is why I *never* quote on a job, before being there in person to see what is / is not available.

As you correctly state though, strictly speaking SANS does NOT require you to use separate DBs, provided it is split appropriately internally, and labeled accordingly. Alternative supplies (Be it PV, Generators, UPSes, Inverters, whatever) is covered by section 7.12, and there is no specific mention of a requirement for a dedicated board. Not in section 7.12, nor anywhere else in SANS10141 that I can find.

EDIT: If you get those that 'insist' on it, ask them for proof / relevant clauses that stipulates this.

 

[savage]

BTW...

A single (white) panel'ed DB board, with 1 'mains breaker' and 1 'alternative power' breaker, having say 5 10A breakers and 5 20A breakers, is NOT clear seperation. Even though you have an breaker marked 'alternative power', there is still uncertainty as to which of the 10A and 20A breakers are fed from which supplies (if that makes sense). In other words, I can switch off your 'alternative supply', but I still won't know which of your 10A or 20A breakers are energized or not. This is a good example of a single (split) DB, which does NOT have adequate separation.

A 2x18-Way board (Where you have 2 rows), can possibly be properly separated, by MARKING AN ENTIRE ROW, as alternative power. When I now switch off your 'alternative power' breaker on row 2, provided it is marked correctly, it is relatively safe to presume the entire second row will be disconnected. This, may pass, but will still be frowned upon.

A CLEARLY SEPARATED DB...
View attachment 227584

Whilst it is still one DB, you have CLEAR undisputed separation (separate panels). White = Normal Power, Blue = Emergency Power, which is sort of an industry standard.

The bottom of the line is, your separation MUST BE idiot proof. Any person, must be able to stand in front of your DB, and immediately see, and understand the separation that has been done - be it youself, an electrician troubleshooting a fault, or the electrical inspector standing there ready to write out fines...