A friend sent me a manufacturer spec tag for a 5KVA Mecer inverter and I was curious. Minimum VOC 120V and 450V max with 18A max on the MPPT side.

He has 7 x 330W panels and this suggests that he should just clip them in series. The cable PV 6mm² cable should have no issues handling the 9A (cable can handle upto 60A adjacent).

Does anyone know of this inverter?

1 hour ago, Kalito said:

Does anyone know of this inverter?

It's a Voltronic Power Axpert MKS II, also known as a PIP-5048MG. No use in Australia or elsewhere with strict rules, since there is no insulation monitoring, and the panels are higher than ELV voltage. Very convenient to wire the panels if you can get away with it. I wonder how these will fare post February though; in a sense they'll be "even more not on the list" than other Axperts, since they won't be on the list, and won't even be able to get there because of their design.

Edited December 17, 20187 yr by Coulomb

Aah what are the considered norm? Explain like to a dummy the following:

• Insulation monitoring

• ELV voltage

Interesting

On 2018/12/17 at 8:27 PM, Kalito said:

• Insulation monitoring

That's where a machine tests regularly that both sides of the PV array are floating electrically, i.e. there is no leakage to earth. This is a necessity in many jurisdictions, if the array voltage is hazardous. 

Quote

• ELV voltage

Extra Low Voltage. The hazardous voltage line has to be drawn somewhere, and it's usually called at 120 volts of ripple free DC, or 50 VAC. There seems to be a push towards even lower voltages, like 60 VDC. Lower than this is called extra low voltage, and while it can hurt a human with dry skin, it's unlikely to kill.

Over extra low voltage, it becomes low voltage, which is considered lethal. House power points are LV. It is possible to be rescued from contact with LV, and electricians train for this. 

There is medium and high voltage after that. 

So safely protocols vary depending on the risk. For low voltage (lethal) solar panels, it's possible to make say a roof silently lethal. Hence the requirement in many jurisdictions for insulation monitoring, and regulations about how persistent the alarm has to be, etc.

And if it keeps the government bureaucracy busy, so much the better (edit: from their point of view). But there is a legitimate safety concern too. 

Edited December 18, 20187 yr by Coulomb
Trimmed some bad info

I might add that while third party insulation monitors are expensive, of the same order as an Axpert inverter, I don't think it would cost much to add to an inverter. 

But the cost is likely in proving that the system is adequate for the task. Fried customers because a cheap relay failed open circuit is a bad look. 

I don't know about Australia but in South Africa anything below 1000v is termed low voltage and covered in South African Bureau of Standards low voltage installation regulations.

Needless to say, 240v @ 50Hz Ac (our standard wall outlet) is already crazy dangerous, never mind 1000v.

Medium voltage is up to 22kV, used for distribution in metropolitan areas. And anything above that is high voltage for large scale distribution.

All our cities have transformers shared by blocks of homes/businesses, Delta-wye configuration and depending where you live you almost always have either single phase (new areas) or 3 phase (old areas, especially Cape Town). Typical home breaker is 60amps (single phase) or 50amps (3 phase so 150amps total). Businesses typically have 80amp breakers (single or 3 phase)

Edited December 17, 20187 yr by Gnome

13 minutes ago, Gnome said:

I don't know about Australia but in South Africa anything below 1000v is termed low voltage and covered in South African Bureau of Standards low voltage installation regulations.

Needless to say, 240v @ 50Hz Ac (our standard wall outlet) is already crazy dangerous, never mind 1000v.

Medium voltage is up to 22kV, used for distribution in metropolitan areas. And anything above that is high voltage for large scale distribution.

All our cities have transformers shared by blocks of homes/businesses, Delta-wye configuration and depending where you live you almost always have either single phase (new areas) or 3 phase (old areas, especially Cape Town). Typical home breaker is 60amps (single phase) or 50amps (3 phase so 150amps total). Businesses typically have 80amp breakers (single or 3 phase)

Same here (Zambia). Where the heck did you get the round plug from though? It wreaked harvoc so much the Bureau of Stds had to outlaw appliances with round plugs. We use 13A square UK type. SA is 16A. I note that even MCBs are minimum 16A now.

Residential supply breaker is also 60A.

1 minute ago, Kalito said:

Same here (Zambia). Where the heck did you get the round plug from though? It wreaked harvoc so much the Bureau of Stds had to outlaw appliances with round plugs. We use 13A square UK type. SA is 16A. I note that even MCBs are minimum 16A now.

Residential supply breaker is also 60A.

Do you mean this plug:

It is an old British plug. Probably South Africa got power widely sooner than Zambia and right now it is hard to transition. It is a bad plug for several reasons tho:

1. Huge
2. Sizes vary so often can't fit two plugs next to each other and the sizes aren't strictly regulation
3. Ground pin is bigger than the live/neutral which is laughable stupid
4. Spacing between pins are oversized for no good reason
5. You can get fingers in there

The new plug is a IEC standard if I'm not mistake:

This plug is actually pretty decent. It addresses all the points above and is backward compatible with the 2 pin Euro style plug.

UK/British plugs are just too big in my opinion and suffer from some of the same issues their older version does.

And frankly the EU plug is the worst plug I've ever encountered and I feel sorry for them. Bad design for so many reasons

US probably has the best plugs overall (although I think the new SA plug with ground is slightly smaller). The sizes are regulated, they are compact and un-switched.

3 minutes ago, Gnome said:

It is an old British plug

If you ever need to know why anything in the world is the way that it is, ask the British. It's either their fault, or they are somehow involved in it anyway.

@Gnome I could not help but notice the illegal SA fixture at M&B Mandahill - Lusaka as I worked away. Oddly I was equiped with my travel adapter. This socket has your “new” plug configuration as well😂

I don't really get the sudden opposition people have to the old style plug. It held up amazingly well. The longer earth pin: That means it makes contact first and releases last. The shutter-design... means it is easier to get a plug in. Ask those poor Europeans how hard you have to push sometimes to get a plug past the shutters. Live and Neutral can't be easily swapped (again... in Europe you have no such assurances). If you use a decent quality socket, those bulky pins means a larger contact surface. If you don't break the shutter mechanism, fingers cannot get in (this still works perfectly on all the sockets in my house after more than a decade... but fails terribly on the plastic multiplug adapters within months -- didn't spend enough money :-) ).

Now these new IEC ones. At least its an international standard even if just two countries use it :-) But unless this is better than the average two-pin plug we already know (and despise... isn't chopping it off and fitting a 3-pin one of the first things you do?) I doubt it is going to be better.

But I suppose time will tell.

36 minutes ago, plonkster said:

I don't really get the sudden opposition people have to the old style plug. It held up amazingly well. The longer earth pin: That means it makes contact first and releases last. The shutter-design... means it is easier to get a plug in. Ask those poor Europeans how hard you have to push sometimes to get a plug past the shutters.

That is true of the new plug also. But the fact that the earth pin is so much thicker than the other two pins is a huge flaw

Additionally the fact that there is so much space between pins and the plug you are able to get your fingers under the plug while pushing it in or pulling. This happens especially when you try to grip a stubborn plug and end up with a finger between live & neutral.

36 minutes ago, plonkster said:

 If you don't break the shutter mechanism, fingers cannot get in

Alternatively make the pins small enough that you can't get fingers in in the first place

The fact that fingers can fit in with our current plugs is a flaw, rather than shutters being a feature.

36 minutes ago, plonkster said:

Now these new IEC ones. At least its an international standard even if just two countries use it :-) But unless this is better than the average two-pin plug we already know (and despise... isn't chopping it off and fitting a 3-pin one of the first things you do?) I doubt it is going to be better.

I have replaced all my 3 pin in my home with 3pin + new ZA plug. The new plug points work great for EU plugs. In fact I've started to hate the old 3 pin plug

Edited December 18, 20187 yr by Gnome

3 hours ago, Gnome said:

But the fact that the earth pin is so much thicker than the other two pins is a huge flaw

Why? Sure... it's a waste, but I half suspect it has to be that big in order to provide enough movement to move the shutters.

3 hours ago, Gnome said:

you are able to get your fingers under the plug while pushing it in or pulling

Yes, that is definitely a problem.

3 hours ago, Gnome said:

I have replaced all my 3 pin in my home with 3pin + new ZA plug. The new plug points work great for EU plugs. In fact I've started to hate the old 3 pin plug

That is good to hear. I can imagine that it's a real treat when you have 7 cellphone chargers in the house (as we do nowadays).

40 minutes ago, plonkster said:

but I half suspect it has to be that big in order to provide enough movement to move the shutters.

Ah yes that actually makes sense

40 minutes ago, plonkster said:

That is good to hear. I can imagine that it's a real treat when you have 7 cellphone chargers in the house (as we do nowadays).

Well I bought 3 different types and tested them (CBI, Crabtree and some other brand). Between them I found one that worked well.

Yeah I know it is excessive but I hate plugs that are sticky or too loose, etc.

4 minutes ago, Gnome said:

Yeah I know it is excessive but I hate plugs that are sticky or too loose, etc.

And hence my gripe with every 2-pin out there. When you get to the point that you have to wiggle it to get good contact... that is usually when it gets snipped off and replaced by a 3-pin :-)

I’m a big fan of the new socket. I put them all over my house using the socket with one old style and three new.

you can forget about the crappy adapters, all my 2 pins fit tightly with no issues - and so nice and small.

I use the 3 pin plug for devices that need earth. Not such a fan of the Crabtree plug which is hard to open,  it once done it does the job and is much much better designed than the 15A plug which is a design used in the UK before the 2nd world war...