240v Shorepower/Inverter Switch & RCD

Jokani

Jokani

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I am looking at putting in a switch to manually swap from shorepower to inverter.

Is this the correct way to go about it:

shorepower-inverter.jpg


The switch I am thinking of using is here:

http://www.ebay.co.uk/itm/25-Amp-3-Pole-Rotary-Change-Over-Switch-On-Off-On-TCS6S343-33301-/171345203289
 
GaryCottam said:
I am looking at putting in a switch to manually swap from shorepower to inverter.

Is this the correct way to go about it:

[

The switch I am thinking of using is here:

http://www.ebay.co.uk/itm/25-Amp-3-Pole-Rotary-Change-Over-Switch-On-Off-On-TCS6S343-33301-/171345203289
Click to expand...

Its called a "transfer switch". Goggle it

2 pole is adequate. No need to switch the earth. Most important feature is the intermediate off position (or at least to be off of break before make design)


Not sure about the positioning of the RCD. ISO 13297* shows in in the shore power supply to the switch ... but says there should be one in every AC power supply.

(* Looking at the 2012 edition but there are several ambiguities in that ... really need sight of a 2014 edition! )
 
Last edited:
VicS said:
Its called a "transfer switch". Goggle it

2 pole is adequate. No need to switch the earth. Most important feature is the intermediate off position (or at least to be off of break before make design)


Not sure about the positioning of the RCD. ISO 13297* shows in in the shore power supply to the switch ... but says there should be one in every AC power supply.

(* Looking at the 2012 edition but there are several ambiguities in that ... really need sight of a 2014 edition! )
Click to expand...
Should he not connect neutral to earth at the inverter, so switching the earth becomes important.
 
superheat6k said:
Should he not connect neutral to earth at the inverter, so switching the earth becomes important.
Click to expand...

Yes inverter should have the neutral earthed


But what I meant was make all the earth connections permanent rather than switched.


See annexed diagrams in the later editions of Iso 13297
 
GaryCottam said:
I am looking at putting in a switch to manually swap from shorepower to inverter.

Is this the correct way to go about it:

shorepower-inverter.jpg


The switch I am thinking of using is here:

http://www.ebay.co.uk/itm/25-Amp-3-Pole-Rotary-Change-Over-Switch-On-Off-On-TCS6S343-33301-/171345203289
Click to expand...

I have the same setup except my switch is 4 position off, shore power, inverter, generator.

Earth MUST be connected to neutral at inverter other wise RCD will not work.

Don't forget GI connected to incoming earth line from shore power and I think the earth would need switching to only have he GI in circuit when shore power is connected as GI not needed when inverter is in circuit.

I also have MCB in each of my line to appliances to protect the cables from current overload as not all RCD include current overload. If yours do separate MCB may not be needed.
 
VicS said:
Yes inverter should have the neutral earthed


But what I meant was make all the earth connections permanent rather than switched.


See annexed diagrams in the later editions of Iso 13297
Click to expand...

I don't have access to the ISO, but I understood it was important not to have two earth to neutral connections on any system, so this means the changeover switch should switch both live and neutral from the inverter, otherwise when on shore power the neutral / earth connection at the inverter would still be in circuit.
 
superheat6k said:
I don't have access to the ISO, but I understood it was important not to have two earth to neutral connections on any system, so this means the changeover switch should switch both live and neutral from the inverter, otherwise when on shore power the neutral / earth connection at the inverter would still be in circuit.
Click to expand...

Iso 13297 shows the neutrals of all the sources being permanently earthed . Only one neutral ( and one live ) is switched onto the system at any one time.


This diagram shows a generator as the additional power source as an example. ( there is a diagram with an inverter but its one with auto transfer switching ... even so its neutral is permanently earthed)

(IMO, and for that matter according to the text, there should be an RCD in the generator or inverter output but the diagram only shows a circuit breaker)


Fig%20D1%20ISO%2013297.2012_1.jpg
 
Rogershaw said:
Earth MUST be connected to neutral at inverter otherwise RCD will not work.
Click to expand...

Hi Roger, any chance you (or anyone else) could expand on how I would achieve this?

FYI - The inverter is a 'Sterling ProPower 1000w Quasi Sine Wave' it has a single plug socket that I was going to take the cable form this plug in to the A/C distribution panel.
 
I decided to go for a combined switchMCB/RCD

gemini-ac-distribution-panel.jpg


The instructions consist of a simple table, I have started making some notes in blue, but I am unsure of a couple of points:

  1. The ring main live/neutral/earth all want to return to complete a loop?
  2. The earth also needs to be joined to the 12v earth main 12v earth stud?
 
GaryCottam said:
Hi Roger, any chance you (or anyone else) could expand on how I would achieve this?

FYI - The inverter is a 'Sterling ProPower 1000w Quasi Sine Wave' it has a single plug socket that I was going to take the cable form this plug in to the A/C distribution panel.
Click to expand...

My inverter has the same and all I did was to connect the earth pin to the neutral pin in the plug. This could also be done inside the inverter at the output power mains socket but in my case no one can get to my inverter without stripping out some paneling mine cannot be changed by mistake.

This is my mains distribution panel. The lower one has all the overload circuits to each appliance.

The next one up has the source selector switch and RCD's for each source supply and there are 2 neons to show correct phase connection and an earth fault.

IMGP3002_zpsu7haizxl.jpg
 
One question

Rogershaw, thank you for the picture and only curious if you had any advice or guidance of orienting your MCB horizontally in the lower part of your panel. Or does anyone else know how this is regarded, electrically?

Thank you
 
Aurai said:
One question

Rogershaw, thank you for the picture and only curious if you had any advice or guidance of orienting your MCB horizontally in the lower part of your panel. Or does anyone else know how this is regarded, electrically?

Thank you
Click to expand...

Both my mains and my 12VDC distribution panels have mini circuit breakers mounted that way and I have had no problem in the last 8 years. My previous also had the same arrangement without any issues.
 
Time to fit this now, but there is something I am not sure of.

When I switch to inverter power, will I need to make sure that the 240v battery charger is switched off, otherwise, I will be draining 12v to convert to 240v and back again? Hope that makes sense? Or is there a way to install that ensures the 240v charger is onlys switched when on shorepower?
 
I would install a separate MCB for the battery charger connected between the shore power RCD and power change over switch, this would mean it can only be powered from the shore power, but assuming this is a combined inverter charger you would need to check how this is set up by the makers, as I would expect there is an internal wiring design to prevent this situation, but I do not have sufficient knowledge of combined DC Inverter / chargers.
 
superheat6k said:
I would install a separate MCB for the battery charger connected between the shore power RCD and power change over switch, this would mean it can only be powered from the shore power, but assuming this is a combined inverter charger you would need to check how this is set up by the makers, as I would expect there is an internal wiring design to prevent this situation, but I do not have sufficient knowledge of combined DC Inverter / chargers.
Click to expand...

Don't think the Sterling is a combines inverter/charger, so i'd go with your suggestion of fitting a separate mcb before the changeover switch for the charger.
 
Nothing is ever easy is it ;-)

My switchover unit is combined with the MCB& RCD, all in one unit, so unless I bin it, I can't fit a separate MCB between.

I can fit either just an MCB or an MCB + RCD before the changeover switch, just for the battery charger, is there any advantage in an additional RCD.

I am also tempted just to wire the charger in before the MCB/RCD/Change over switch - it has been that way for years, and at least I am now protecting 9 out of 10
 
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