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230VAC Source Switching


rupertbear

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As part of my refit, I am about to install a system for switching between 230VAC sources, as shown by Gibbo at:

http://www.smartgauge.co.uk/nb_ac_sys.html

The version I will be using is the one with the 4-way manual switch, credited by Gibbo to John Gwalter.

Is John a user of CWDF?

Has anyone else used this method?

There is one aspect of the design which concerns me, the possibility of an internal fault within the switch.

A direct Live-Neutral short when connected to a shore line could rely on an unknown remote trip. (If it occurs when connected to my inverter, there are electronic output overload controls and physical fuses at the input.)

I don't know what the likelihood of switch failure is, nor potential failure modes. Am I worrying unnecessarily? Would it be worth looping the shoreline live input through an extra MCB in the CU before the switch?

It's not that I consider the switch to be unreliable, it just doesn't feel 'right' to have equipment upstream of the consumer unit!

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I think you are worrying unnecessarily, most (if not all) switches that can do the job will actually be made of several individual switches stacked together so in reality live and neutral are actually being switched separately (even though both switches are being moved by the same control)

 

the switch you end up with will probably be something similar to the one pictured below, you can see from the image that there is actually three switches stacked behind the control (for switching Live, Neutral and Earth)

 

post-9998-0-34474900-1475139362_thumb.jpg

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There is a rule in the relevant ISO requirement, that you have to have a breaker within 0.5 metres of the shore power inlet, or within 3 metres of a shore power inlet socket if the cabling is trunked etc, but you'll probably comply with that and ultimately you don't have to comply with the ISO though of course it is "best practice".

 

The actual switch itself is unlikely to be an issue, more vulnerable is the wiring as per the above.

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we have a Victron inverter charger with it's built in auto switch between inverter and incoming mains - but as we are now paying quite a lot for electricty I would like to be able to switch the charger function off whilst powering the sockets from the shore power, could I use the same switching?

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we have a Victron inverter charger with it's built in auto switch between inverter and incoming mains - but as we are now paying quite a lot for electricty I would like to be able to switch the charger function off whilst powering the sockets from the shore power, could I use the same switching?

Just turn the charging current down to zero. However I would almost guarantee that using shore power to generate 12v will be far cheaper than doing it via the engine or a generator.

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Just turn the charging current down to zero. However I would almost guarantee that using shore power to generate 12v will be far cheaper than doing it via the engine or a generator.

the obvious solution is simply to switch the charging part off but the victron seems incapable of this turning down to zero involves taking the cover off and fiddling with the dip switches even then i have a feeling that current would be used by its little computer

as for charging I am looking at when we leave the boat, no load on the batteries apart from the Victron and the solar should keep them topped up in winter, so i would like to power just the sockets and not the Victron ( to have a frost heater plugged in to shore mains)

  • Greenie 1
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we have a Victron inverter charger with it's built in auto switch between inverter and incoming mains - but as we are now paying quite a lot for electricty I would like to be able to switch the charger function off whilst powering the sockets from the shore power, could I use the same switching?

They would be no benefit, as the charger is providing your 12v directly as well so it's more efficient and better for the batteries keeping it on.

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errr.

 

with the batteries fully charged then the charger will be almost zero load.

 

With combi ON and charger On the Victron will, if set up correctly (storage mode), maintain the batteries by doing a short absorption phase (duration settable) every few days (duration settable) eg. absorption for 1 hr every 7 days.

 

I cannot see any reason for turning of the charger.

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There is a rule in the relevant ISO requirement, that you have to have a breaker within 0.5 metres of the shore power inlet, or within 3 metres of a shore power inlet socket if the cabling is trunked etc, but you'll probably comply with that and ultimately you don't have to comply with the ISO though of course it is "best practice".

 

The actual switch itself is unlikely to be an issue, more vulnerable is the wiring as per the above.

That explains to me why our boat, which has shore power inlets at bow and stern, has a breaker tucked away in a cupboard just inside the boat at the bow end. Took me month's to find it having thought that the front inlet plug was maybe not connected or faulty. Your a knowledgeable man Nick.
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That explains to me why our boat, which has shore power inlets at bow and stern, has a breaker tucked away in a cupboard just inside the boat at the bow end. Took me month's to find it having thought that the front inlet plug was maybe not connected or faulty. Your a knowledgeable man Nick.

Do you have a change over switch between them?

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errr.

 

with the batteries fully charged then the charger will be almost zero load.

 

With combi ON and charger On the Victron will, if set up correctly (storage mode), maintain the batteries by doing a short absorption phase (duration settable) every few days (duration settable) eg. absorption for 1 hr every 7 days.

 

I cannot see any reason for turning of the charger.

I've just taken some measurements

With absolutely nothing switched on .1 kwh used in 4.5 hours equivalent to .55 kwh per day, presumably the isolation transformer keeping itself warm so nothing I can do about that short of bypassing that too.

But with the Victron switched on, but again no other load and the solar panels generating enough to maintain steady state in the batteries

.1 kwh in 1 hour 20 minutes or an extra 1.2 kwh approx per day which with electric costing .33 euros per kwh is about 40 pence per day or £12 per month.

 

Added to which I would rather not leave a powerful battery charger connected unattended for long periods in case a fault condition arises with the batteries.

 

I could turn down the Victron settings but I think it would still take current just keeping itself warm and thinking, added to which I would need to reset it every time I visit the boat through the winter (which involves moving the settee, cutting all electric, removing Victron case and fiddling with barely visible microscopic dip switches which I suspect are not designed for repeated use.)

 

Hence I would just like to check how best to safely switch the sockets between Victron output and direct to iso transformer. Switching the Victron off could be part of this function (as belt and braces) though it does have an everything off setting.

Edited by Phoenix_V
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I've just taken some measurements

With absolutely nothing switched on .1 kwh used in 4.5 hours equivalent to .55 kwh per day, presumably the isolation transformer keeping itself warm so nothing I can do about that short of bypassing that too.

But with the Victron switched on, but again no other load and the solar panels generating enough to maintain steady state in the batteries

.1 kwh in 1 hour 20 minutes or an extra 1.2 kwh approx per day which with electric costing .33 euros per kwh is about 40 pence per day or £12 per month.

 

Added to which I would rather not leave a powerful battery charger connected unattended for long periods in case a fault condition arises with the batteries.

 

I could turn down the Victron settings but I think it would still take current just keeping itself warm and thinking, added to which I would need to reset it every time I visit the boat through the winter (which involves moving the settee, cutting all electric, removing Victron case and fiddling with barely visible microscopic dip switches which I suspect are not designed for repeated use.)

 

Hence I would just like to check how best to safely switch the sockets between Victron output and direct to iso transformer. Switching the Victron off could be part of this function (as belt and braces) though it does have an everything off setting.

That contactor I linked to will do it automatically and the rotary switch will do it manually. You would wire it up so the IT feeds both the Victron and the input of the switch and the Victron out feeds the other input of the switch. The out of the switch goes to the consumer unit. If you go for the contactor it does use some electric when switched but this can be wired to be either from the inverter or shore.

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Another way would be too cut the shore line connection using a relay/contactor from the solar controller. How this can be done depends on the controller of course. A lot have a relay that can be controlled by a low voltage (or genny control), this way if the voltage gets too low or you turn on something of high load to lower the voltage it will turn the shore power feed on. This method could also be done by a battery monitor like the BMV's as well.

Edited by Robbo
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Doesn't switching the Victron off achieve what you want? Incoming mains direct to sockets?

You would think that but in practice it is either nothing (off position) at all or charger plus sockets

That contactor I linked to will do it automatically and the rotary switch will do it manually. You would wire it up so the IT feeds both the Victron and the input of the switch and the Victron out feeds the other input of the switch. The out of the switch goes to the consumer unit. If you go for the contactor it does use some electric when switched but this can be wired to be either from the inverter or shore.

thanks, that sounds sensible

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You would think that but in practice it is either nothing (off position) at all or charger plus sockets

I guess there must be a reason...

 

In that case, yes a changeover switch or a contactor would do the job for you.

 

Cheers,

Tony

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