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Advice sought re. battery replacement


Froggy

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Just now, Mike the Boilerman said:

 

Hmmm I wouldn't expect this to trip the RCD as this is a device to detect current leakage outside of the primary circuit.

It ought to trip the MCB or fuse though. Assuming you have one. I'd be very wary of his advice as he doesn't seem to grasp the purpose of the RCD.

 

It's possible that I'm misquoting him, but i'm inclined to do a bit of research on our particular model and maybe even contact Victron for some advice.

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4 minutes ago, Robbo said:

The Combi Victron will bond the earth and neutral together when not receiving mains power.  

Hi, this is interesting. So what are the implications of this? How does the Victron isolate the power in situations when there is a short to the hull, for example?

EDIT: Ours is an Atlas Combi 12/1500/50

Edited by Froggy
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24 minutes ago, Froggy said:

Hi, this is interesting. So what are the implications of this? How does the Victron isolate the power in situations when there is a short to the hull, for example?

EDIT: Ours is an Atlas Combi 12/1500/50

There is no implications as this is what is needed when your not on shore power for the RCD to work correctly.  If the Atlas doesn't do this then it's a big safety flaw.

Edited by Robbo
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1 minute ago, Robbo said:

There is no implications as this is what is needed when your not on shore power for the RCD to work correctly.

What worries me is that when the guy doing the electrical work tested one of the mains sockets nothing tripped when he shorted it. He said that this is potentially lethal but took the cover off the Combi and couldn't find any obvious fault or evidence of bodging. I think he mentioned something about there not being an earth wire but from what you've said maybe this is part of the design. The trouble is that the last owners did quite a lot of bodge jobs on the boat so i don't know whether to believe the guy who tested the socket about being very wary or the boat fitter's assurance that the Inverter circuit is protected against shocks and short circuits.

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4 minutes ago, Froggy said:

What worries me is that when the guy doing the electrical work tested one of the mains sockets nothing tripped when he shorted it. He said that this is potentially lethal but took the cover off the Combi and couldn't find any obvious fault or evidence of bodging. I think he mentioned something about there not being an earth wire but from what you've said maybe this is part of the design. The trouble is that the last owners did quite a lot of bodge jobs on the boat so i don't know whether to believe the guy who tested the socket about being very wary or the boat fitter's assurance that the Inverter circuit is protected against shocks and short circuits.

Shorted what to what? Live to earth or live to neutral?    The earth wire is part of the Victron design, when in inverter mode it connects it to the neutral wire.  It sounds like you need someone who knows about boat electrics to have a look, not a general electrician as these are basic boat electric issues and easy to find the fault if any.

Edited by Robbo
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8 minutes ago, Robbo said:

Shorted what to what? Live to earth or live to neutral?    The earth wire is part of the Victron design, when in inverter mode it connects it to the neutral wire.  It sounds like you need someone who knows about boat electrics to have a look, not a general electrician.  

I honestly can't remember exactly what he said, it was over a month ago. You might have a point though, because although he's obviously been doing work for various boat owners for some time he seems a bit of an odd job man rather than a specialist electrician. I got the impression that he was used to newer Victrons and that ours didn't respond to his tests as he'd expected from previous experience. If i remember correctly (and i may be wrong) i think he said something to the effect that there didn't seem to be an earth connection when the 240v socket he tested was being powered by the Victron.

Edit: Just to clarify, these tests were carried out when our immersion heater started tripping the shoreline circuit breaker every time it was turned on. This turned out to be a burned out (shorted) element, but the guy tested one of the 240v sockets as part of his initial fault finding.

Edited by Froggy
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For just over a tenner buy one of these: http://m.ebay.co.uk/itm/131968584436?_mwBanner=1

Not only will it give you a visual display of all connections being present (N-L-E) but it also has an RCD test button. 

You can make your own RCD test plug with a 6k8 4W resistor wired across L-E, or a 40W light bulb similarly wired but the above plug-in tester is simple, effective, cheap and safe. 

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9 hours ago, Froggy said:

Hi, this is interesting. So what are the implications of this? How does the Victron isolate the power in situations when there is a short to the hull, for example?

EDIT: Ours is an Atlas Combi 12/1500/50

Most inverters with a 240V pass through feature have an internal relay (might can be configured on some).  When shore power is being supplied to the craft the relay is set to pass the shore power to your sockets and immersion etc.  If there is an live to earth fault then either or both the RCD on your craft or on the shore supply bollard will trip.  When on inverter power the relay will operate and it will disconnect the shore supply from your sockets and connect the inverter to your sockets.  It must do this otherwise you could pump 240v back into the shore supply.  The other function of this relay is (assuming this is how it is set up) to bond the inverter neutral and earth together, this way a fault between live and earth will allow a current to flow through the craft earth and back into the inverter neutral so tripping the RCD in your consumer unit.  If this link is missing then the RCD probably will not trip in the event of a live to earth fault.  It sounds like your faulty immersion heater only tripped on shore power and not when on inverter power.  In which case it would indicate that this link is missing.  Do not add this link yourself as  from your questions you do not fully understand how your system should be configured as you could make the vessel very unsafe, talk to someone that knows about boat electrical systems.

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On ‎31‎/‎03‎/‎2017 at 09:04, Chewbacka said:

Most inverters with a 240V pass through feature have an internal relay (might can be configured on some).  When shore power is being supplied to the craft the relay is set to pass the shore power to your sockets and immersion etc.  If there is an live to earth fault then either or both the RCD on your craft or on the shore supply bollard will trip.  When on inverter power the relay will operate and it will disconnect the shore supply from your sockets and connect the inverter to your sockets.  It must do this otherwise you could pump 240v back into the shore supply.  The other function of this relay is (assuming this is how it is set up) to bond the inverter neutral and earth together, this way a fault between live and earth will allow a current to flow through the craft earth and back into the inverter neutral so tripping the RCD in your consumer unit.  If this link is missing then the RCD probably will not trip in the event of a live to earth fault.  It sounds like your faulty immersion heater only tripped on shore power and not when on inverter power.  In which case it would indicate that this link is missing.  Do not add this link yourself as  from your questions you do not fully understand how your system should be configured as you could make the vessel very unsafe, talk to someone that knows about boat electrical systems.

Many thanks for your very informative answer, I will see if we can get somebody to take a look, although the boat did pass the recent BSS examination.

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52 minutes ago, Froggy said:

Many thanks for your very informative answer, I will see if we can get somebody to take a look...

Probably cheaper (and certainly more convenient) to buy a tester as suggested...

 

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1 hour ago, Froggy said:

Many thanks for your very informative answer, I will see if we can get somebody to take a look, although the boat did pass the recent BSS examination.

That's good to know, at least when the 'baddies' come to syphon your diesel they will know which tank to use, the BSS is no much use for anything else.

 

Sorry - were you under the misapprehension that it improved safety ?

Edited by Alan de Enfield
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2 minutes ago, Alan de Enfield said:

That's good to know, at least when the 'baddies' come to syphon your diesel they will know which tank to use, the BSS is no much use for anything else.

They could swap the diesel label for the pumpout label, that would give the syphoners somthing to chew on.

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2 hours ago, Froggy said:

Many thanks for your very informative answer, I will see if we can get somebody to take a look, although the boat did pass the recent BSS examination.

Perhaps this might help understanding of the BSS test?

http://canalworld.net/forums/index.php?/topic/77727-boat-safety-certification/#comment-1607937

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3 hours ago, Alan de Enfield said:

That's good to know, at least when the 'baddies' come to syphon your diesel they will know which tank to use, the BSS is no much use for anything else.

 

Sorry - were you under the misapprehension that it improved safety ?

Ha ha, no, I was gobsmacked about how much the BSS overlooked when I read up about it. They don't even seem to worry about whether or not you have smoke alarms or CO detectors, absolutely essential imo, but seem over concerned about the configuration of engine fuel lines etc.

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9 minutes ago, Froggy said:

Ha ha, no, I was gobsmacked about how much the BSS overlooked when I read up about it. They don't even seem to worry about whether or not you have smoke alarms or CO detectors, absolutely essential imo, but seem over concerned about the configuration of engine fuel lines etc.

It's more for third party safety rather than personal safety.   CO and smoke alarms are now in the BSS for hire boats.

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46 minutes ago, Froggy said:

Ha ha, no, I was gobsmacked about how much the BSS overlooked when I read up about it. They don't even seem to worry about whether or not you have smoke alarms or CO detectors, absolutely essential imo, but seem over concerned about the configuration of engine fuel lines etc.

Why, its up to you if you want to kill yourself. Anyway if it was mandatory all the people with generators inside the back doors would have to take the batteries out.

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15 minutes ago, Mike the Boilerman said:

 

Why is a label required on the pump out cap then?

Hardly a big risk to other boaters.

 

Because if the boatyard man puts diesel in it you might kill him?????

..............Dave

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I love how this thread has wandered WAY off topic! Lots of forum purists hate this, but I learn a lot by the process, as you would in a natural conversation, which rarely stays on topic, especially when a few beers are involved. (Cue in-depth discussion on real ale :lol:)

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