LuxPower - emergency backup enabling

[marshman]

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[openspaceman]

Okay, staying with the subject of small generators and slightly derailing; if the house is islanded and earthing by an earth spike, running a normal consumer unit, will the RCDs still react to a L to E fault if the generator is not earthed? Logically a circuit cannot complete so the RCD will not see the inbalance

[Oldgreybeard]

Okay, staying with the subject of small generators and slightly derailing; if the house is islanded and earthing by an earth spike, running a normal consumer unit, will the RCDs still react to a L to E fault if the generator is not earthed? Logically a circuit cannot complete so the RCD will not see the inbalance

Simple answer is that for the RCDs to be guaranteed to operate within their specs for time and current, then two things need to be present. First is that neutral and earth must be linked at the generator, second is that the earth electrode resistance must be low enough to ensure that the 30mA earth leakage trip current can be reached without the voltage on the earthed equipment exposed conductive parts exceeding 50V (the safe touch voltage).

To meet both these requirements just means connecting earth to neutral at the generator (taking note of the uncertainty about generator configurations mentioned earlier) and having an earth electrode providing the protective earth that has a resistance (Ra) that is lower than 1,667 ohms. In reality, although 1,667 ohms is safe, the guidance is that the value of Ra should be lower than 200 ohms when measured at the time of installation. The reason for the lower value is to allow for natural variation in earth electrode resistance with the weather (they go low in very wet weather, higher in very dry weather).

[openspaceman]

So a simple test is to open the 3 pin shutter of the generator output when it is not running and measure resistance between N and E? If Near 0 Ohms bond E to earth spike?

[Oldgreybeard]

So a simple test is to open the 3 pin shutter of the generator output when it is not running and measure resistance between N and E? If Near 0 Ohms bond E to earth spike?

Yes, that would be an OK check to do.

[stevevoller]

I am not an electrical engineer so please excuse me if this is a stupid question.

I have a Luxpower ACS 3600 and Growatt min 6000 (with 5.4KW PV) that are AC connected to the house and grid.

The PV powers the house load, them charges the battery and if anything is left exports to the grid.

Is it possible when a power cut occurs to have the system switch to powering the house from the EPS, whilst keeping the PV powering the house and charging the battery.

From what I have read in the manual the normal operation would be to have the EPS (powered by battery only) drive a separate consumer unit with specific parts of the house load.

This seems really poor use of the system and will fail once the battery is expired. I understand the safety reason for turning off the output of the inverters when they are grid connected.

But is it possible to somehow have a transfer switch that will disconnect the grid and connect the EPS to the house load? whilst also allowing the use of the use of the PV?

I read and partially understood the long thread about Earthing, if we had a separate earth for the house installed is that ok?

[Tinbum]

No you can't run the pv inverter off the eps as the eps circuit can't charge the battery.

[Stinsy]

I am not an electrical engineer so please excuse me if this is a stupid question.

I have a Luxpower ACS 3600 and Growatt min 6000 (with 5.4KW PV) that are AC connected to the house and grid.

The PV powers the house load, them charges the battery and if anything is left exports to the grid.

Is it possible when a power cut occurs to have the system switch to powering the house from the EPS, whilst keeping the PV powering the house and charging the battery.

From what I have read in the manual the normal operation would be to have the EPS (powered by battery only) drive a separate consumer unit with specific parts of the house load.

This seems really poor use of the system and will fail once the battery is expired. I understand the safety reason for turning off the output of the inverters when they are grid connected.

But is it possible to somehow have a transfer switch that will disconnect the grid and connect the EPS to the house load? whilst also allowing the use of the use of the PV?

I read and partially understood the long thread about Earthing, if we had a separate earth for the house installed is that ok?

1) The Lux has a UPS not an EPS function. EPS is powered only in an outage, UPS is always powered.

2) You could totally have a changeover switch that swapped the whole house from grid to UPS circuits. But doing so wouldn’t be a good idea. Better would be to have one dedicated sockets circuit and maybe your lighting on the UPS circuit.

3) There are some very important earthing issues to resolve if using the UPS circuit.

[stevevoller]

Thank you for the reply it is appreciated, I am just trying to understand enough so I can explain enough to the electricians as to how I would like things to work.

(I went back and read the manual for the ACS 3600 and you are correct it does say UPS)

Where are you suggesting the placement of the manual transfer switch in the system ?

What I don't understand is in the event of a power cut and the manual transfer switch being used, what am I switching?
1. The separate "UPS" consumer unit from main AC to UPS on ACS3600? That would leave the Growatt PV, output from the ACS3600 and rest of the house still connected to the grid in an off state..
2. Something else?

Is there a way to keep the solar inverter on so at least some of the remaining house load and potentially battery can be charged?

Am I asking too much for a standard home install, should I just give up and get some kind of hybrid inverter?

At the moment I have everything quite optimised except for power cuts which are a bit to frequent.
1. PV powers house first,
2. if excess PV and battery is not fully charged, then charges battery,
3. if battery is fully charged and car is plugged in then send excess PV to the Zappi charger,
4. and finally the export to grid.

[Tinbum]

The problem is that if the solar inverter is producing more than the house load and the battery is full the LUX has to be able to tell the PV inverter to throttle back. If it can't then you have problems. I don't believe it has that facility and can't accept power in on the output..

You may be able to do it but would have to have automatic loads come on.