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Creating a shore-power failure alarm.


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As forum members may have deduced by now - I struggle with understanding electricity, though I will undertake wiring jobs (but only) when I feel I understand all the implications and processes of a particular exercise.

 

Three times in the last few years when on a serviced mooring I've experienced the 230v shore-power supply tripping, (once because I'd over-loaded the damn thing :blush:) and a couple of times because the marina was having supply problems.

 

There's always the possibility that it may happen without me being aware, of course, and that would have the result that if not attended to it may cause the battery bank to be run down beyond acceptable levels.

 

May I ask the experts how they would wire up an alarm, ( audible preferably) that would alert one to such shore-power failure.

 

My current set-up has shore-power coming in to the boat via a consumer unit (with a discrete rcd for shore supply) to a Victron Multiplus 12/3000/120.

 

Logic tells me that the alarm would need to detect when the landline switch is turned to activate on the consumer unit, but the power fails

 

How should I wire in an alarm please?

 

 

 

I thank you in anticipation. ;)

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The remote panel for the Combi on our boat has an 'AC present' indication - so it's a clear indication that the external supply has failed - does G&F have nothing similar??

 

It duplicates the one on the combi itself but that sits in a cupboard

Edited by The Dog House
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As forum members may have deduced by now - I struggle with understanding electricity, though I will undertake wiring jobs (but only) when I feel I understand all the implications and processes of a particular exercise.

 

Three times in the last few years when on a serviced mooring I've experienced the 230v shore-power supply tripping, (once because I'd over-loaded the damn thing :blush:) and a couple of times because the marina was having supply problems.

 

There's always the possibility that it may happen without me being aware, of course, and that would have the result that if not attended to it may cause the battery bank to be run down beyond acceptable levels.

 

May I ask the experts how they would wire up an alarm, ( audible preferably) that would alert one to such shore-power failure.

 

My current set-up has shore-power coming in to the boat via a consumer unit (with a discrete rcd for shore supply) to a Victron Multiplus 12/3000/120.

 

Logic tells me that the alarm would need to detect when the landline switch is turned to activate on the consumer unit, but the power fails

 

How should I wire in an alarm please?

 

 

 

I thank you in anticipation. ;)

A large and powerful 240v siren could be mounted and connected into the incoming mains supply cable in the back of your boat.

This siren will sound continuously 24/7 telling you that the supply is alive. When the siren goes silent the supply will have failed. :closedeyes:

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A large and powerful 240v siren could be mounted and connected into the incoming mains supply cable in the back of your boat.

This siren will sound continuously 24/7 telling you that the supply is alive. When the siren goes silent the supply will have failed. :closedeyes:

 

Doh! - Fancy - - and I didn't think of that! :cheers: - I could even have an array of those rotating emergency service lights running too - - in case I became too accustomed to the siren!

 

The remote panel for the Combi on our boat has an 'AC present' indication - so it's a clear indication that the external supply has failed - does G&F have nothing similar??

 

It duplicates the one on the combi itself but that sits in a cupboard

 

Aye - - it does, but the remote is tucked away in the wheelhouse, and I wish to rig up an audible to provide a warning that would command our immediate attention.

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On our boat if we were on mains we only ever had the combi - switched over to charger. So if the external mains failed we lost all 240V.

 

As such a simple plug in freezer alarm would have alerted us that the mains had failed... would this not suffice?

 

Something like this??

 

http://www.alphahatch.com/intelec-power-alarm-plug-ah654120-97-p.asp

Edited by The Dog House
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I think you might need some sort of mains relay switch wired into the incoming mains supply. With 12v wired into the relayed side of it. When the supply fails its contacts throw over and switch in the 12v supply to sound a 12v horn, bleeper or siren.

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I think you might need some sort of mains relay switch wired into the incoming mains supply. With 12v wired into the relayed side of it. When the supply fails its contacts throw over and switch in the 12v supply to sound a 12v horn, bleeper or siren.

That's absolutely right.

You can buy ready-made such as this box.

But you could make it yourself for a lot less. There are articles on the web (search for 'mains failure alarm'). It depends on your confidence in building it!

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As forum members may have deduced by now - I struggle with understanding electricity, though I will undertake wiring jobs (but only) when I feel I understand all the implications and processes of a particular exercise.

 

Three times in the last few years when on a serviced mooring I've experienced the 230v shore-power supply tripping, (once because I'd over-loaded the damn thing :blush:) and a couple of times because the marina was having supply problems.

 

There's always the possibility that it may happen without me being aware, of course, and that would have the result that if not attended to it may cause the battery bank to be run down beyond acceptable levels.

 

May I ask the experts how they would wire up an alarm, ( audible preferably) that would alert one to such shore-power failure.

 

My current set-up has shore-power coming in to the boat via a consumer unit (with a discrete rcd for shore supply) to a Victron Multiplus 12/3000/120.

 

Logic tells me that the alarm would need to detect when the landline switch is turned to activate on the consumer unit, but the power fails

 

How should I wire in an alarm please?

 

 

 

I thank you in anticipation. ;)

 

How weird is this post? On Saturday I bought November issue of Practical Boat Owner and on page 51, lo and behold there is an article on how to build an alarm for shore power failure, using a few bits and pieces from Maplins including a Velleman Sound Generator kit I expect to have it finished in the next couple of days and will let you know the results. Can't believe your question posting while I'm sitting surrounded by little bits and pieces of schoolboy electronic stuff!

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How weird is this post? On Saturday I bought November issue of Practical Boat Owner and on page 51, lo and behold there is an article on how to build an alarm for shore power failure, using a few bits and pieces from Maplins including a Velleman Sound Generator kit I expect to have it finished in the next couple of days and will let you know the results. Can't believe your question posting while I'm sitting surrounded by little bits and pieces of schoolboy electronic stuff!

 

Spooky indeed! (Tho' it is near Halloween - - )

 

I look forward to learning of your experiences!

 

_________________________________________________________________________________________________________________________

and many thanks also to Bizz. , Bottle, Keble and The Dog House - - -

 

Your comments and suggestions shall be researched, and acted on, as soon as I've finished this post!

 

 

 

Cheers everybody

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The only problem with the one linked to is, it would need to be wired before the combi on the shoreline into the boat. ;)

 

Not a major problem. :closedeyes:

 

The real problem with it is that it will permanently alarm when not connected to shorepower. It if has an on/off switch then that will simply get switched off and forgotten about thus making the alarm pointless.

 

It's actually not such a simple problem to crack. How is the device supposed to know the difference between an accidental shorepower failure and a deliberate shorepower failure? If it has to rely on a human remembering to switch it on and off, then why not simply rely on the human to manually check that shorepower is still on?

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The real problem with it is that it will permanently alarm when not connected to shorepower. It if has an on/off switch then that will simply get switched off and forgotten about thus making the alarm pointless.

 

It's actually not such a simple problem to crack. How is the device supposed to know the difference between an accidental shorepower failure and a deliberate shorepower failure? If it has to rely on a human remembering to switch it on and off, then why not simply rely on the human to manually check that shorepower is still on?

Reed Switch and magnet on the plug and socket on the shore supply lead, plugged in and its on, unplugged and its off. You could probably even mount a microswitch to detect that a lead has been plugged in.

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about the simplest way would be 2 mains relays, one on the mains only side of the c/o switch, the other on the inverter supported side. Wire a normally closed contact on each in series and use them to switch a low voltage sounder. Sounder will only go off when BOTH relays are de-energised. presumeably if all the power was off the batteries would be isolated as well.

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It's actually not such a simple problem to crack. How is the device supposed to know the difference between an accidental shorepower failure and a deliberate shorepower failure? If it has to rely on a human remembering to switch it on and off, then why not simply rely on the human to manually check that shorepower is still on?

 

 

Fully agree. The use cases would be "interesting" to say the least, especially for an automatic solution. About 20 years ago we tried to develop an algorithm that remembered users settings depending on who last used the device. On paper it was really simple however we discovered that no two people used it in the same way and the algorithm got very complex trying to accommodate all of the variation. We ended up pulling the feature and to this day I've not seen the same feature offered in the marketplace.

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On our boat if we were on mains we only ever had the combi - switched over to charger. So if the external mains failed we lost all 240V.

 

That would be my preferred setting on shore power if I had a combi. The alarm is starting to get a bit too complicated.

Edited by blackrose
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