Good day to all

I am preparing and mounting components required for an Inverter and Battery installation before our electrician will come to finalize the installation. I have a few questions regarding the MCB for the Inverter (Inverter Output) on the Essentials side.

The Sunsynk Datasheet for a 5.5KW model states a Max Continuous AC Pass-Through current of 35A.

1. May I assume that this will still be the Max Pass-Through current when the Grid is active?
2. If so... the manual states a 32A breaker on the essentials side but would a 35A be good or would I rather stick to the 32A breaker?
3. My house is wired in a rather limited way with only 2 lights breakers and 2 plugs breaker which limits my choice of plugs to put on the Essentials side without re-wiring. I will of course have a ChangeOver switch between Grid, Inverter and Essentials Side. If I move both plugs breakers to the Essentials side but still wanted to not limit myself when having the Grid power the Essentials Side (Grid selected on ChangeOver) then could I put the Inverter Output Breaker (35A) before the ChangeOver but have a 63A breaker after the ChangeOver? Wiring will obviously match the breakers required. See attached image.

Thank you

Edited February 20, 20233 yr by TheMac

2 hours ago, TheMac said:

Good day to all

could I put the Inverter Output Breaker (35A) before the ChangeOver but have a 63A breaker after the ChangeOver? Wiring will obviously match the breakers required. See attached image.

Thank you

 

Not sure if I understand the question.

The inverter output IS before the changeover and the 63A IS after the changeover. Follow the direction of power flow through the changeover switch.

What is the rating of the changeover switch? It is a bad idea to exceed the recommended output breaker size because if you go there, the inverter won't be able to supply the load if the power trips. The 63A breaker should be supplying the changeover switch.

@Scorp007 @frivan

I think my question #3 was a bit unclear. Let's see if I can clarify.

To help with that there are a few points to take note of:

• I have 2 plug breakers on the original/non-essential DB
• I have 2 light breakers on the original/non-essential DB
• I will move all the plug and light breakers to the Essential DB. I have to because I don't want to re-wire house plugs to separate heavy loads from small loads.
• I will have a 63A change-over switch feeding from the Non-Essential DB and also from the Inverter. The change-over will output into the Essentials DB.
• Sunsynk 5.5K Inverter has max continuous pass-through of 35A. I am not sure if that is only while Grid is off (Loadshedding) or not. For the sake of the question I will assume it will always be 35A irrespective of whether Grid is available or not.
• If change-over is set to the Inverter side then obviously we will only have 35A available for the Essiential DB
• If change-over is set to the Grid side then I want full 63A availability for the Essiential DB

Considering the above points my original question #3 was to find out if it is allowed to put the 35A breaker that is fed from the Inverter, before the change-over and then have a 63A breaker after the change-over to protect when Grid side is selected on the change-over.

BUT I thought about it a bit and would like to present the following diagram. Will this (diagram) make more sense and will it be allowed by standards?

Edited February 22, 20233 yr by TheMac

You have 3 Earth Leakages, you should have one. Don't supply the CO with an EL. Put one EL downstream from the CO. Supply mains to the CO with a breaker (preferably less than 63A).

I have done something similar as per my attached diagram. In my diagram read Main DB as Non-essentials DB and Garage DB as Essential DB. Depending on your requirements, you may need 2 EL's. Old SANS regs was that you only needed an EL on plug circuits. Latest SANS regs require EL on stove and geyser as well. Your inverter should not be fed from an EL, this is one of the primary causes of EL nuisance tripping. My inverter size is different from yours so your CB sizes will differ.