Interested minds ... (boat electrical systems, the 'Big picture').

[T_i_m]

28 minutes ago, Eeyore said:

A quick reminder for some, and maybe news to others:

In a world full of standards there is no such thing as standard. 😉

Or if there is, does everyone follow them?

 

Dad was a member of the BSI (lifting equipment) and often when attending some European meeting where they were discussing some standard or other he noticed that some delegates were more 'involved' than others.

 

On a break he asked a couple of the 'less interested' delegates why they weren't and their reply was basically that they (their country) wasn't going to take much notice of the std, no matter what was set.

[Mike Tee]

When you get to the Travel Power contact

fourcountiesmarineservices.com

[nicknorman]

1 hour ago, T_i_m said:

When you stated the Combi units typically had one ac input I immediately thought 'so how to we deal with 'shore'  and 'Travel-power' but then you answered that at the end. 😉

 

One further question if I may ... do I read you right that there could well be at least a couple of ac outlet circuits, like where you see raw mains and UPS > generator outlets in hospitals / datacentres?

 

Some Combi units have 2 ac inputs, the Victron Quattro springs to mind I think. Most have 1 though.

 

Yes so there could be a couple of ac outlet circuits. Some people like to wire high energy demand circuits (mostly the immersion heater) to the output that is only live when there is ac input. The other output is either ac input passed through, or inverter output. This is to prevent eg an immersion heater from draining the batteries. In our case we don't do that because, having Lithium batteries, I want to be able to run the immersion heater (which is only 1kw) from them if I so desire. It is up to me to ensure that I don't flatten the batteries!

 

The other thing I should mention is that combi inverter chargers tend to have a front panel 3 way switch that is something along the lines of "On", "Off", "Charger only".

In "Off", everything is dead even if shore power is connected. In "On" there is automatic selection of shore power or inverter power. In "Charger Only" the shore power is sent to the battery charger side of things, and passed through to the boat's sockets etc. But if the shore power fails, everything goes dead. This is to prevent an unnoticed failure/disconnection of the shore power from flattening the batteries.

 

Finallly I will mention neutral earth bonding. In order for a Residual Current Device (RCD) to operate, the neutral and earth (NE) need to be tied together "at source", but nowhere else further downstream. So for shore power, NE bonding happens off the boat at the transformer/sub-station etc. However when operating on inverter power, it is necessary for NE bonding to happen within the inverter. So the inverter has an NE bonding relay which is open when on shore power, and closes when operating on inverter only.

 

Finally2 some power sources such as the travelpower, instead of outputting live at +_ 230v and neutral at the same voltage as earth, are centre tapped meaning that live is +-115v and neutral is -+115v. Trying to bond N to E would create a massive short circuit and the Travelpower would be toast. But no matter, without NE bonding the RCD will still operate to protect life if there is a human connection between live or neutral, and earth. When there is a centre tapped supply such as the Travelpower, it is appropriate to use double pole breakers and RCD so that in the event of a trip, both L and N are disconnected.

 

Edited September 4 by nicknorman

[MtB]

1 hour ago, Eeyore said:

A quick reminder for some, and maybe news to others:

In a world full of standards there is no such thing as standard. 😉

 

Very true.

 

Reminds me of the apochryphal tale about the group of engineers who noted there were 8 different standards about <something>, so the set about writing an over-arching standard to encompass them all. 

 

Result: 9 different standards.

[T_i_m]

2 hours ago, nicknorman said:

 

Some Combi units have 2 ac inputs, the Victron Quattro springs to mind I think. Most have 1 though.

 

Yes so there could be a couple of ac outlet circuits. Some people like to wire high energy demand circuits (mostly the immersion heater) to the output that is only live when there is ac input. The other output is either ac input passed through, or inverter output. This is to prevent eg an immersion heater from draining the batteries. In our case we don't do that because, having Lithium batteries, I want to be able to run the immersion heater (which is only 1kw) from them if I so desire. It is up to me to ensure that I don't flatten the batteries!

 

The other thing I should mention is that combi inverter chargers tend to have a front panel 3 way switch that is something along the lines of "On", "Off", "Charger only".

In "Off", everything is dead even if shore power is connected. In "On" there is automatic selection of shore power or inverter power. In "Charger Only" the shore power is sent to the battery charger side of things, and passed through to the boat's sockets etc. But if the shore power fails, everything goes dead. This is to prevent an unnoticed failure/disconnection of the shore power from flattening the batteries.

 

Finallly I will mention neutral earth bonding. In order for a Residual Current Device (RCD) to operate, the neutral and earth (NE) need to be tied together "at source", but nowhere else further downstream. So for shore power, NE bonding happens off the boat at the transformer/sub-station etc. However when operating on inverter power, it is necessary for NE bonding to happen within the inverter. So the inverter has an NE bonding relay which is open when on shore power, and closes when operating on inverter only.

 

Finally2 some power sources such as the travelpower, instead of outputting live at +_ 230v and neutral at the same voltage as earth, are centre tapped meaning that live is +-115v and neutral is -+115v. Trying to bond N to E would create a massive short circuit and the Travelpower would be toast. But no matter, without NE bonding the RCD will still operate to protect life if there is a human connection between live or neutral, and earth. When there is a centre tapped supply such as the Travelpower, it is appropriate to use double pole breakers and RCD so that in the event of a trip, both L and N are disconnected.

 

Once again, thank you very much for all that Nick. I can see how there are many 'gotchas' you need to be aware of with all this, luckily, most of the concepts I am fairly familiar.

 

When Mum was selling their (60's) house after Dad died the Mrs and I went round there to give access to various trades to come in and do their tests and inspections. [1]

 

The electrician went into the garage and after a while came out and asked me 'did you re-wire the garage / workshop?' I had but wasn't sure I wanted to implicate myself but said 'yes' anyway (because I had a few years earlier). He then said, 'why didn't you re-wire the house as well ...?' 😉

 

I was also reminded the other day that I'd run some SWA for a family friend to power their pond pump when I was 15 and that (or at lest the feed) was still working 50 years later. 😉

 

[1] I had to fit the base panel back on the boiler (that he didn't need to take off anyway) for the gas fitter / inspection as he didn't seem able. ;-(

Edited September 4 by T_i_m

[David Mack]

12 hours ago, Eeyore said:

A quick reminder for some, and maybe news to others:

In a world full of standards there is no such thing as standard. 😉

https://xkcd.com/927/

 

[1st ade]

22 hours ago, Eeyore said:

In a world full of standards there is no such thing as standard.

https://xkcd.com/927/

OK - David beat me to it - by several hours...

[Tacet]

On 04/09/2024 at 11:32, Alan de Enfield said:

 

 

 

Yes the RCR does require RCD installation - but as MTB so frequently points out ' which specification do you work to' ?

.

The RCR does not require an RCD installation.

[nicknorman]

3 minutes ago, Tacet said:

The RCR does not require an RCD installation.

I disagree. Can you cite any evidence for that statement?
Although obviously, the RCR (by means of the relevant ISO) only requires an RCD to be installed if there is an ac mains system on the boat.

[Alan de Enfield]

11 minutes ago, Tacet said:

The RCR does not require an RCD installation.

 

Is there an alternative that achieves what an RCD does, that has documentary evidence that it is equivalent ?

 

The RCD does not require mandatory use of the ISO specs (except in a limited number of applications)  but it does requires any alternative method to provide the same results / protection - and you must provide evidence to prove it.

 

The actual text extracts :

 

Article 31: Presumption of conformity

Where a conformity assessment body demonstrates its conformity with the criteria laid down in the relevant harmonised standards or parts thereof the references of which have been published in the Official Journal of the European Union it shall be presumed to comply with the requirements set out in Article 30 in so far as the applicable harmonised standards cover those requirements.

 

But – in a later paragraph the concept of what happens if the boat is ‘not built to the ISO standards, or Non ISO standard components  are used”

 

 4. Verification of conformity by examination and testing of every product

4.1. All products shall be individually examined and appropriate tests set out in the relevant harmonised standard(s) and/or technical specifications, or equivalent tests, shall be carried out in order to verify conformity with the approved type described in the EC-type examination certificate and with the appropriate requirements of the legislative instrument. In the absence of such a harmonised standard, the notified body concerned shall decide on the appropriate tests to be carried out.

4.2. The notified body shall issue a certificate of conformity in respect of the examinations and tests carried out, and shall affix its identification number to each approved product or have it affixed under its responsibility. The manufacturer shall keep the certificates of conformity available for inspection by the national authorities for 10 years after the product has been placed on the market.

 

[Tacet]

24 minutes ago, nicknorman said:

I disagree. Can you cite any evidence for that statement?
Although obviously, the RCR (by means of the relevant ISO) only requires an RCD to be installed if there is an ac mains system on the boat.

Yes.  You have identified the first obvious anyway.

 

Here is a link to the Essential Requirements of the RCR 2017.

https://www.legislation.gov.uk/uksi/2017/737/schedule/1

"Electrical systems shall be designed and installed so as to ensure proper operation of the watercraft under normal conditions of use and shall be such as to minimise risk of fire and electric shock.

 

All electrical circuits, except engine starting circuits supplied from batteries, shall remain safe when exposed to overload.

 

Electric propulsion circuits shall not interact with other circuits in such a way that either would fail to operate as intended.

 

Ventilation shall be provided to prevent the accumulation of explosive gases which might be emitted from batteries. Batteries shall be firmly secured and protected from ingress of water."

 

There is nothing about Residual Current Devices.  You can, of course, have a view that an RCD is, in practice, necessary to comply with the requirements - but it is not a point-blank requirement

 

 

13 minutes ago, Alan de Enfield said:

 

Is there an alternative that achieves what an RCD does, that has documentary evidence that it is equivalent ?

 

 

There is no point blank requirement to have an RCD - so there is no requirement to produce documentary evidence that an alternative is equivalent.

[nicknorman]

1 minute ago, Tacet said:

Yes.  You have identified the first obvious anyway.

 

Here is a link to the Essential Requirements of the RCR 2017.

https://www.legislation.gov.uk/uksi/2017/737/schedule/1

"Electrical systems shall be designed and installed so as to ensure proper operation of the watercraft under normal conditions of use and shall be such as to minimise risk of fire and electric shock.

 

All electrical circuits, except engine starting circuits supplied from batteries, shall remain safe when exposed to overload.

 

Electric propulsion circuits shall not interact with other circuits in such a way that either would fail to operate as intended.

 

Ventilation shall be provided to prevent the accumulation of explosive gases which might be emitted from batteries. Batteries shall be firmly secured and protected from ingress of water."

 

There is nothing about Residual Current Devices.  You can, of course, have a view that an RCD is, in practice, necessary to comply with the requirements - but it is not a point-blank requirement

 

But as Alan has pointed out, the easiest and most sensible way to comply with the RCR is to comply with the ISO. If you don’t want to comply with the ISO then you would have to demonstrate an equivalent level of safety. I challenge you to do that without using an RCD. So I think your pedantic point is that it doesn’t specifically say you have to use an RCD. However it is unfeasible to comply with the RCR without doing so (assuming ac mains on board), and so I think your point is unhelpful to other people and somewhat pointless.

[Tacet]

Just now, nicknorman said:

But as Alan has pointed out, the easiest and most sensible way to comply with the RCR is to comply with the ISO. If you don’t want to comply with the ISO then you would have to demonstrate an equivalent level of safety. I challenge you to do that without using an RCD. So I think your pedantic point is that it doesn’t specifically say you have to use an RCD. However it is unfeasible to comply with the RCR without doing so (assuming ac mains on board), and so I think your point is unhelpful to other people and somewhat pointless.

Agreed an RCD is almost invariably sensible - but it's not mandatory.  That may be pedantic - but it's also true.

 

It is incorrect to say that if you don't comply (you probably mean meet) with the ISO then you have to demonstrate an equivalent level of safety.  To comply with the RCR you need to comply with the Essential Requirements.  No more, no less.

 

The RCR contains a presumption that if you meet the ISOs you have complied with the Essential Requirements.  But it is a rebuttable presumption - and, of course, there can always be an argument about whether you have, in fact, met the ISOs.

30 minutes ago, Alan de Enfield said:

 

 

Article 31: Presumption of conformity

Where a conformity assessment body demonstrates its conformity with the criteria laid down in the relevant harmonised standards or parts thereof the references of which have been published in the Official Journal of the European Union it shall be presumed to comply with the requirements set out in Article 30 in so far as the applicable harmonised standards cover those requirements.

 

But – in a later paragraph the concept of what happens if the boat is ‘not built to the ISO standards, or Non ISO standard components  are used”

 

 4. Verification of conformity by examination and testing of every product

4.1. All products shall be individually examined and appropriate tests set out in the relevant harmonised standard(s) and/or technical specifications, or equivalent tests, shall be carried out in order to verify conformity with the approved type described in the EC-type examination certificate and with the appropriate requirements of the legislative instrument. In the absence of such a harmonised standard, the notified body concerned shall decide on the appropriate tests to be carried out.

4.2. The notified body shall issue a certificate of conformity in respect of the examinations and tests carried out, and shall affix its identification number to each approved product or have it affixed under its responsibility. The manufacturer shall keep the certificates of conformity available for inspection by the national authorities for 10 years after the product has been placed on the market.

 

Where is this Article 31 etc please?  I don't think it is the Recreational Craft Regulations, is it?

[nicknorman]

23 minutes ago, Tacet said:

Agreed an RCD is almost invariably sensible - but it's not mandatory.  That may be pedantic - but it's also true.

 

It is incorrect to say that if you don't comply (you probably mean meet) with the ISO then you have to demonstrate an equivalent level of safety.  To comply with the RCR you need to comply with the Essential Requirements.  No more, no less.

 

The RCR contains a presumption that if you meet the ISOs you have complied with the Essential Requirements.  But it is a rebuttable presumption - and, of course, there can always be an argument about whether you have, in fact, met the ISOs.

 

It is pedantic and I can’t see how your point has any practical usefulness.

[Tony Brooks]

I suppose a suitable RCBO would do the job, but I suppose it is just an RCD with extras.

[nicknorman]

1 minute ago, Tony Brooks said:

I suppose a suitable RCBO would do the job, but I suppose it is just an RCD with extras.

Yes that is what we have.

[Alan de Enfield]

1 hour ago, Tacet said:

Where is this Article 31 etc please?  I don't think it is the Recreational Craft Regulations, is it?

 

The RSGis the technical arm of the RCD authorities and was formed to give interpretation to the requirements to ensure consistent application of the requiremenst by the Notified Bodies.

 

RECREATIONAL CRAFT SECTORAL GROUP (RSG) GUIDELINES 2023 SG Copyright © 2023 European Communities, Prepared by Recreational Craft Sectoral Group (RSG) Technical Secretariat, c/o Abertech snc Via Dante 48, 38068 Rovereto (TN) ITALY Tel: +39 0464 486333, Fax: +39 0464 350380

 

The Recreational Craft Sectoral Group (RSG) The Recreational Craft Sectoral Group (RSG), consisting of all Notified Bodies and other parties with valid interest, has been established to assist in the uniform application and interpretation of the actual version of the Recreational Craft Directive (RCD). The composition of RSG comprises the following parties: · Notified Bodies · The Commission · The Recreational Craft Industry · User Organisation · European Standardisation Bodies

 

They have distributed the following explanation to the Notified Bodies :

 

Relevant paragraphs :

 

 

Article 31: Presumption of conformity

Where a conformity assessment body demonstrates its conformity with the criteria laid down in the relevant harmonised standards or parts thereof the references of which have been published in the Official Journal of the European Union it shall be presumed to comply with the requirements set out in Article 30 in so far as the applicable harmonised standards cover those requirements.

 

And, where the ISO is not followed the product used will be tested in accordamce to the tests set out in the ISO document

 

4. Verification of conformity by examination and testing of every product

4.1. All products shall be individually examined and appropriate tests set out in the relevant harmonised standard(s) and/or technical specifications, or equivalent tests, shall be carried out in order to verify conformity with the approved type described in the EC-type examination certificate and with the appropriate requirements of the legislative instrument. In the absence of such a harmonised standard, the notified body concerned shall decide on the appropriate tests to be carried out.

4.2. The notified body shall issue a certificate of conformity in respect of the examinations and tests carried out, and shall affix its identification number to each approved product or have it affixed under its responsibility.The manufacturer shall keep the certificates of conformity available for inspection by the national authorities for 10 years after the product has been placed on the market.

 

 

The RSG is also responsible for interpetation (and circulation of the decision) for questions raised to them by Notified Bodies.

 

A couple of recent examples :

 

 

 

 

 

Edited September 5 by Alan de Enfield

[Peanut]

There is lots of good advice given above, particularly about regulations and narrow boat specifics, but there is one book that tackles many aspects of boat workings, and that is the, "Boat Owner's Mechanical and Electrical Manual." It does have a lumpy boat bias, but covers all the major boat systems, as well as specifically lumpy ones. It is well regarded, but you have to understand the technical content, which should be no problem with your background. Best to get it from the library, or see a copy in a bookshop or chandlery, as it is not cheap, £50+.

https://www.amazon.co.uk/Boatowners-Mechanical-Electrical-Manual-Essential/dp/1472946677

[MtB]

6 minutes ago, Peanut said:

There is lots of good advice given above, particularly about regulations and narrow boat specifics, but there is one book that tackles many aspects of boat workings, and that is the, "Boat Owner's Mechanical and Electrical Manual." It does have a lumpy boat bias, but covers all the major boat systems, as well as specifically lumpy ones. It is well regarded, but you have to understand the technical content, which should be no problem with your background. Best to get it from the library, or see a copy in a bookshop or chandlery, as it is not cheap, £50+.

https://www.amazon.co.uk/Boatowners-Mechanical-Electrical-Manual-Essential/dp/1472946677

 

And as no-one seems to have mentioned it so far, a book may not be necessary given Tony Brooks' free web pages on all this sort of stuff. 

 

http://tb-training.co.uk/cover.html

[Peanut]

Just now, MtB said:

 

And as no-one seems to have mentioned it so far, a book may not be necessary given Tony Brooks' free web pages on all this sort of stuff. 

 

http://tb-training.co.uk/cover.html

I quite agree, but as he has a technical background, I thought he might like to consider a comprehensive text on the subject. Not free or narrow boat specific, but would benefit his prior experience.

[T_i_m]

1 hour ago, Peanut said:

I quite agree, but as he has a technical background, I thought he might like to consider a comprehensive text on the subject. Not free or narrow boat specific, but would benefit his prior experience.

If I wasn't a carer for my wife (dementia), awaiting the result of my recent Prostate Cancer treatment (get your PSA checked please guys)  and probably too old to start such a new 'project', I think I'd like to offer my services to 'boaters needing help' because, I've spent my whole life in 'Support' roles (commercial and friends and family etc)  and 'fixing things' is what I love to do. 😉

 

We were dog walking along the tow-path (R Lea) a while back and noticed a mature lady having trouble with the padlock on her narrow boat.  She had actually unlocked it (and had the key etc) but the shackle had got jammed in the hasp. I offered to help, she accepted and with the aid of my Leatherman PST 11 (as Dad always used to say, 'A sailor without a knife ...' (or a multitool in this case)), I soon got her sorted. 😉 

 

Opening / closing sluices and gates for people who are single handed and who accept the offer of help is also fun and rewarding. 😉

 

As an aside, anyone who has lived with someone with dementia probably knows how lonely it can be so there is also the social contact and conversation when providing help, something that often seems to be very much part of the 'boating community'.

 

Just as you guys have already proven to me etc. 😉

 

[T_i_m]

Back.

 

So, I managed to get onboard my friends NB this afternoon to have a closer look at his Travel power thing.

 

Basically there was a braided loom of 3 + 2 cables attached to the TP alternator that I believe 'just' needs re-connecting. I didn't trace them through but would they go directly to a 'Victron Phoenix Multi 12 Plus'?

 

[nicknorman]

No. The alternator is a conventional alternator BUT rewound as a high voltage variable frequency ac source, something like 300 volts I think. The braided cable is because the voltage is so high. This is connected to the travelpower “black box” (which might be black or silver according to its version) which contains the electronics to convert it into 230v ac 50Hz.

 

So a Travelpower comprises 2 separate items, the alternator, and the box of electronics.

Edited September 17 by nicknorman

[T_i_m]

Hi Nick and thanks for the reply.

 

So, the TP alternator wouldn't feed directly into the 'Victron Phoenix Multi Plus 12 3000 120, but 'another' box or another box first ... ?

 

I have taken pictures of all the boxes, panels, batteries and switches and most of them make sense individually and am gathering all the datasheets, schematics and manuals I can to help me understand them better.

 

As an aside, his old bilge pimp was permanently wired to 12V via the 'Automatic' feed with a push button 'Manual override' but has recently been rewired via a 3 way rocker switch providing On / Off / Momentary. This seems a bit vulnerable (compared to the original install) as it's easy to accidentally knock the switch into the 'Off' position?

 

I get why it might be good (required?) to be able to completely isolate that specific supply via a switch but maybe it's just the wrong type of switch or in the wrong location (where it could be knocked off by a bag of coal etc)?

Edited September 17 by T_i_m

[blackrose]

On 04/09/2024 at 08:49, Alan de Enfield said:

 

I was simply pointing out that it is incorrect to say that an RCD MUST be used.

 

 

Yes I understood what you were pointing out. I on the other hand was simply pointing out that you'd written that as a negative thing when in fact it's a positive thing as it exceeds the safely standards. 

On 04/09/2024 at 09:03, MtB said:

It never ceases to amaze me how much trouble so many people have distinguishing between mandatory requirements, and things which are optional but actually very good practice and well worth doing. 

 

If you were referring to me I have no trouble distinguishing between the two. If you were talking about the author of the Smartgauge website I'm pretty sure Gibbo would find your comment hilarious.