Looking at installing a LS system, any advice would be appreciated.

[Qui_Illustrati]

Ok so system is finally up and running, not 100% yet but close enough, 1x bad connection on MC4 connector so my 1x PV string is not operational yet, will be fixed this weekend.

Problem now is I have to get it registered ASAP. My prepaid meter is giving problems. What I have found is that the unit is actually only a user interface (UI) that communicates to the actual meter which is elsewhere (usually not on the property). It communicates via PLC (power line communication), basically it sends communications to & from the actual meter over the house (grid) wiring. What happens is that when the house (and thus the meter UI as it is pugged into a socket fed from inverter) is supplied by inverter, this communication fails.

Temporary fix was to move the meter UI and connect it directly onto my existing house DB (I left the E/L and a circuit breaker as spare). This way the meter UI is connected to the grid even if the rest of the house is fed from inverter, problem is when my inverter pushes excess power back into the house DB the meter UI sometimes looses connection. So in short I guess I need a new prepaid meter which they will install when I register the system.

You have a clamp sensor right? Correct placement of that should solve your problem

 

[Divan85]

You have a clamp sensor right? Correct placement of that should solve your problem

Jip clamp sensor is there, I had to extend the cable because of the long run, used CAT5 cable for shielding to avoid interference. Works perfectly. Set to always draw 40W from grid. The sensor is on the supply side of the main incomer on the DB, so the unit pushes back power up to that point which means the meter UI is connected downstream of the sensor, hence it still gets power from inverter in that instance.

 

[Qui_Illustrati]

Jip clamp sensor is there, I had to extend the cable because of the long run, used CAT5 cable for shielding to avoid interference. Works perfectly. Set to always draw 40W from grid. The sensor is on the supply side of the main incomer on the DB, so the unit pushes back power up to that point which means the meter UI is connected downstream of the sensor, hence it still gets power from inverter in that instance.

Do you have loads split between essential and non essential?

 

[Divan85]

Do you have loads split between essential and non essential?

Yes, I have my existing DB (non-essential) which feeds the inverter which feeds the inverter DB (essential). So all plugs and lights are on essential and only my stove and geyser is on non-essential. I left the earth leakage and one circuit breaker on the non-essential DB which I am now using to power the prepaid meter UI.

 

[Qui_Illustrati]

Here's my thoughts. Perhaps try moving the CT clamp to the live output on the EL breaker as a test - see if that helps any. Or, just ignore the issue as it's just the keypad interface to the actual meter and the meter isn't tripping if you're not losing power. If you were constantly losing power because of export then that would be a different issue.

 

[Confucius]

Yes, I have my existing DB (non-essential) which feeds the inverter which feeds the inverter DB (essential). So all plugs and lights are on essential and only my stove and geyser is on non-essential. I left the earth leakage and one circuit breaker on the non-essential DB which I am now using to power the prepaid meter UI.

So you have the earth leakage on the main db and another on the essential load db as well?

Are you using the “permanent earth neutral bond”?

The prepaid ciu cannot be on the inverter side and you will have to add a plug onto the non essential db to power this.

 

[SnowmanZA]

So you have the earth leakage on the main db and another on the essential load db as well?

Are you using the “permanent earth neutral bond”?

The prepaid ciu cannot be on the inverter side and you will have to add a plug onto the non essential db to power this.

It looks like he has already figured out that the ui can't be on the inverter side (most likely the filters in the inverter filter out the power line comms). The problem he has now is that the meter ui loses connection sometimes when the inverter exports power.

 

[Confucius]

It looks like he has already figured out that the ui can't be on the inverter side (most likely the filters in the inverter filter out the power line comms). The problem he has now is that the meter ui loses connection sometimes when the inverter exports power.

I get that but that’s a small problem as pointed out by @Qui_Illustrati . As long as the actual meter is not tripping, it isn’t a major problem that the CIU loses connection occasionally.

My questions were more around safety and whether the RCDs are in place especially seeing that he has / will have a little one in his home.

 

[Divan85]

I get that but that’s a small problem as pointed out by @Qui_Illustrati . As long as the actual meter is not tripping, it isn’t a major problem that the CIU loses connection occasionally.

My questions were more around safety and whether the RCDs are in place especially seeing that he has / will have a little one in his home.

Yes I have my existing DB (non-ess) which is the geyser, stove, RCD and 1x plug CB which I left as a spare in case I want to take anything off the inverter supply. Then I have a CB feeding grid supply to the inverter DB. In the inverter DB I then split the grid supply onto a CB that feeds the inverter and also a changeover switch which I can use to bypass inverter and supply essential loads. I also have a CB after the inverter which then feeds the same changeover switch. After the changeover switch I have another RCD which then feeds the CBs for lights and 3x plug circuits.

The UI losing comms is not a major concern, it only happens on occasion and does not affect the supply to the house.

 

[Confucius]

Okay. That seems right.

How about earth neutral bond? Have you installed this? To check if there’s a problem, turn off grid and on the essential db, test the voltage between live and neutral (should be ~220V) and between neutral and earth (should be ~0V). Ive seen many people not test it or not even bother about it.

 

[Qui_Illustrati]

Buy one of these - a tiny price to pay for peace of mind. Test all outlets.

Earth Leakage Tester mt310 230V AC Yellow

Fixed current settings 10mA to 35mA. Neon indication of wiring status. AC voltage indication on LCD display. Double injection rubberized overmould casing. Separate test button. Operating voltage 230V AC. Separate power cord ensures access to all plugs regardless of location. Separate momentary...

leroymerlin.co.za

Kids are prone to sticking their grubby little (adorable) paws in to anything holey - outlets have some protection - easily bypassed though - always good to know the EL breaker would trip saving a life if/when the time comes.

Also - make sure to test both on passthrough (when grid is up) and when loadshedding (grid not up).

 

[Divan85]

Okay. That seems right.

How about earth neutral bond? Have you installed this? To check if there’s a problem, turn off grid and on the essential db, test the voltage between live and neutral (should be ~220V) and between neutral and earth (should be ~0V). Ive seen many people not test it or not even bother about it.

I did read a lot about the earth neutral bond story, what a headache. Apparently it is no longer an issue, but to have peace of mind maybe I should just test it. What the manual states is that the earth on the output of the inverter should not be connected (only for certain countries which includes SA). So no need for the neutral earth bond.

 

[Confucius]

I did read a lot about the earth neutral bond story, what a headache. Apparently it is no longer an issue, but to have peace of mind maybe I should just test it. What the manual states is that the earth on the output of the inverter should not be connected (only for certain countries which includes SA). So no need for the neutral earth bond.

There’s a difference between what the manual says and what SANS says. A CoC will follow SANS and is in place to protect people. You have a child, don’t take chances.

The diagram says that for SA, you should follow local wiring regulations.

if the bond is not in place and your neutral is sitting at 120v, you may also feel a bit of a tingle when you touch appliance bodies.

Just test it as I explained and then decide.

Even installers will tell you it’s not needed, that’s bull.

 

[Divan85]

Ok so happy to confirm I currently have loadshedding so no grid power, perfect time to test earth neutral floating voltage. Opened the inverter DB and measured between earth and neutral. Measured 5V (fluctuating between 4.8 and 5.4V). Forgot to take the earth leakage tester from work yesterday so haven't tested the earth leakage on the inverter DB but will do that when I have a chance.

 

[el3venth]

Kids are prone to sticking their grubby little (adorable) paws in to anything holey - outlets have some protection - easily bypassed though - always good to know the EL breaker would trip saving a life if/when the time comes.

Wow, you have well behaved kids. Mine tend to stick their tongues into/onto things.
Caught the youngest licking the shopping trolly last week. WTF? Why? You are fucking five!