Earth Neutral bond for hybrid inverter (again)

[Mattg4321]

A lot of this foreign made/focused equipment comes with instructions not suitable for the uk imo. EV chargers are another one, although slightly better since the uk regs have stabilised somewhat in the last 4 years or so. 
 

Bottom line is you need someone who knows what they are doing to install it. 

[Dillsue]

I think the grid disconnect is done within the inverter as it is with G98/G99 so no external changeover/disconnect needed?? In the second schematic the "on grid home load" will be dead in a power cut and the "load" will be live, fed from the batteries or generator. If the inverter can't sense a stable grid connection it keeps itself disconnected with internal contactors??

 

In terms of installers knowing the requirements for backup power supplies/generators, are they actually covered in the wiring regs to the level that the regs spell it out in black and white and every spark would know exactly how to wire things?? I've always understood it to be a bit of a grey area??

[Nickfromwales]

24 minutes ago, Dillsue said:

I think the grid disconnect is done within the inverter as it is with G98/G99 so no external changeover/disconnect needed?? In the second schematic the "on grid home load" will be dead in a power cut and the "load" will be live, fed from the batteries or generator. If the inverter can't sense a stable grid connection it keeps itself disconnected with internal contactors??

 

In terms of installers knowing the requirements for backup power supplies/generators, are they actually covered in the wiring regs to the level that the regs spell it out in black and white and every spark would know exactly how to wire things?? I've always understood it to be a bit of a grey area??

Half or more of resellers in the solar trade don’t know, so it’s defo a growing concern as PV / batts / EV / paid export as a working combo is defo on the rise. 

[jimseng]

35 minutes ago, Dillsue said:

I think the grid disconnect is done within the inverter as it is with G98/G99 so no external changeover/disconnect needed?? In the second schematic the "on grid home load" will be dead in a power cut and the "load" will be live, fed from the batteries or generator. If the inverter can't sense a stable grid connection it keeps itself disconnected with internal contactors??

That is correct, although I am going to have a manual changeover in the event of a long term power cut so I can include the heavier, grid side loads if I need to.

 

13 minutes ago, Nickfromwales said:

Half or more of resellers in the solar trade don’t know, so it’s defo a growing concern as PV / batts / EV / paid export as a working combo is defo on the rise. 

I have found that so many installations are retro fitted and the backup load side is ignored and the information is therefore limited for people like me installing into a new build. I guess the costs of rewiring to new DBs is prohibitive. Often there seems to be a couple of sockets to charge mobile phones on the load side.

[Nickfromwales]

13 minutes ago, jimseng said:

That is correct, although I am going to have a manual changeover in the event of a long term power cut so I can include the heavier, grid side loads if I need to.

You can do this off the shelf, and as long as you’re not using the induction hob and a 10.5kW electric shower then the inverter will cope whilst you start running around shutting off these big loads.

 

Wouldn’t need the manual changeover then (which is a bit Fred Flintstone nowadays ). 

[SteamyTea]

19 minutes ago, Nickfromwales said:

bit Fred Flintstone

Or better.

 

 

[Dillsue]

37 minutes ago, jimseng said:

That is correct, although I am going to have a manual changeover in the event of a long term power cut so I can include the heavier, grid side loads if I need to.

 

Just check the max power available on the back up output will power the "heavier" loads. The Solis unit I'm thinking of using is a max of 5kw on the back up output so would need a bit of manual load management if we wanted to cook in the winter with the HP running

[jimseng]

2 hours ago, Nickfromwales said:

Wouldn’t need the manual changeover then (which is a bit Fred Flintstone nowadays ). 

Actually I think it does need human intervention, that is why I am planning it this way. If the grid went down while the immersion, heat pump and cooker were going full tilt it would probably take the inverter out (10kw). That would be annoying. This way I can choose which of the heavier devices I want. The biggest down side to it being manual is that if the oven went out then the soufflé would collapse, but I haven't cooked one in 30 years.

[DamonHD]

That is a new and very introspective version of range anxiety - I salute you!

[jimseng]

7 minutes ago, DamonHD said:

range anxiety

I see what you did there. Good one! 😂

[Nickfromwales]

3 hours ago, jimseng said:

it would probably take the inverter out (10kw)

Nope, it would just throw the breaker that the manufacturer installed to stop you from doing that.

 

Then you reset stuff, after turning off the George Foreman Soufflé maker.

[Mattg4321]

I fitted a manual changeover switch to bypass the inverter in the case of the inverter failing, so I can still get power to the circuits fed from the load terminals of the inverter. 
 

Also, you’re only considering the maximum load going through the inverter to the load terminals when the grid is down. What about under normal usage with grid connected? There is likely to be a limit that might be the same as when grid is down.