Electric wiring conventions and kit

[Tom Richmond]

Hi all,

 

Approaching the wiring of a new fit out (old boat, but gutted back to sprayfoam so all new decisions inside), and would like to get the forums wisdom on wiring.

 

I am going to wire the boat in 24v, using 6v trojans (or similar). Preliminary power audit is calling for around 600ah. Power will come largely from solar. The boat does not have an inboard engine and lives on a permanent mooring with no hook up. Additional charging will come from a generator, and a 240v system will also be installed. I suspect that budget will mean separate mains charger and low power inverter are chosen, rather than an all in one.

 

Lights will be LED throughout. There will also be water pump, shower sump pump, heating circulation pump (water from rayburn back boiler) solar water collector pump, bilge pumps, USB outlets (X8), 12v power outlets (x4 - these will be 24v to the outlet, with a step down converter located behind panel, with cigar socket output.) and a 12v fridge freezer.

 

I have a plan of cable routes, and will run conduit throughout the majority of the boat. I will use crimp connections on all wires, including ferrules for devices with screw connections.

 

I still have a number of questions though:

 

1) In the case of multiple low power devices, such as lights or USB outlets, I will want to wire them in strings (daisy chain). What is the preffered way of connecting three cables together? Piggy back crimps? Two cables into one crimp? Single wires back to junction box and bus bar?

 

2) If I spec my cable thickness for the low current draw of LED lights, it will be insufficient to deal with old fashioned bulbs should anyone install them in the future. Should I allow for this to be on the safe side? Or label the fitting 'LED only'?

 

3) Which suppliers/manufacturers do people prefer, for cable, crimps and conduit.

 

4) What type of conduit do you find best on a boat? I imagine flexible (hoover tube) type being easiest to run in tight spaces, but there are some long straight runs too... Perhaps a combination?

 

5) What about junctions/termination of conduit? I imagine the boxes used in domestic installations can be annoying to fit, any advice here?

 

6) What labelling methods do people prefer? Both in terms of what to buy/use and what numbering system/locations work best.

 

7) Any further hints and tips?

 

Thanks all, and Merry Christmas!

[The Bagdad Boatman (waits)]

One top fitter ran a piano hinge allong the gunwhale with the wireing behind so he could access it anytime. looked good because the hinge was lined very well.

[Chewbacka]

Hi all,

 

Approaching the wiring of a new fit out (old boat, but gutted back to sprayfoam so all new decisions inside), and would like to get the forums wisdom on wiring.

 

I am going to wire the boat in 24v, using 6v trojans (or similar). Preliminary power audit is calling for around 600ah. Power will come largely from solar. The boat does not have an inboard engine and lives on a permanent mooring with no hook up. Additional charging will come from a generator, and a 240v system will also be installed. I suspect that budget will mean separate mains charger and low power inverter are chosen, rather than an all in one.

 

Lights will be LED throughout. There will also be water pump, shower sump pump, heating circulation pump (water from rayburn back boiler) solar water collector pump, bilge pumps, USB outlets (X8), 12v power outlets (x4 - these will be 24v to the outlet, with a step down converter located behind panel, with cigar socket output.) and a 12v fridge freezer.

 

I have a plan of cable routes, and will run conduit throughout the majority of the boat. I will use crimp connections on all wires, including ferrules for devices with screw connections.

 

I still have a number of questions though:

 

1) In the case of multiple low power devices, such as lights or USB outlets, I will want to wire them in strings (daisy chain). What is the preffered way of connecting three cables together? Piggy back crimps? Two cables into one crimp? Single wires back to junction box and bus bar? For low power I put a max of 4 wires into a crimp - 2 at each end. Use a good ratchet crimp tool. Some others will no doubt say this is a bodge. Remember the first wire in the daisy chain takes the current for all following devices so depending on volt drop calcs may need to be thicker.

 

2) If I spec my cable thickness for the low current draw of LED lights, it will be insufficient to deal with old fashioned bulbs should anyone install them in the future. Should I allow for this to be on the safe side? Or label the fitting 'LED only'? The fuse will be sized to match the cable capacity, so if overloaded the fuse will fail. A label to warm the max watts for each fitting is a good idea.

 

3) Which suppliers/manufacturers do people prefer, for cable, crimps and conduit. I used industrial trirated cable as I don't think that tinned is essential for inland waterways. Google is your friend.

 

4) What type of conduit do you find best on a boat? I imagine flexible (hoover tube) type being easiest to run in tight spaces, but there are some long straight runs too... Perhaps a combination? I did not use conduit along the boat, wires are behind a narrow easily removed panel running along both sides of the boat roof. Wires supported by cable ties. When going across the roof or down to the gunnels I did use conduit as it is much easier if you ever want to push another wire through, conduit being behind the wood panels. I used smooth conduit. The problem with corrugated conduit is that wires don't push through so well, especially on gentle bends. Smooth stuff is better, available from toolstation and screwfix.

 

5) What about junctions/termination of conduit? I imagine the boxes used in domestic installations can be annoying to fit, any advice here? Just the end of the pipe for me.

 

6) What labelling methods do people prefer? Both in terms of what to buy/use and what numbering system/locations work best. I did not number my cables, but wish I had. You can get little numbers that slide onto the cable before crimping or ones that clip on after. Not used them, but if I did another boat I would use slide on.

 

7) Any further hints and tips? Have a read of the BSS checklist and the regs for best practice, especially for 240V cables.

 

Thanks all, and Merry Christmas! Merry Christmas

Edited December 22, 2016 by Chewbacka

[Robbo]

1. I'm planning to use Pos-Tap connectors like https://posi-connect.com/collections/posi-tap. But see this discussion http://www.canalworld.net/forums/index.php?showtopic=87390#entry1887142

 

To be honest instead of USB sockets I would use the standard 12v sig lighter connection. USB-C is out now so the old USB will slowly become less used. I would wire these using decent size cable as then you can use for laptop's etc. If you do wire USB sockets, plan for at least 100watt per socket so when/if you do replace with USB-C or future you have suitable wiring.

 

 

3. I've used and will use again as had no issues; www.iem-services.co.uk, mackengineering.co.uk.

I had excellent service from https://www.cclcomponents.com, after a mix up when ordering a incorrect IT (there site was mislabelled) and plan to use them again for purchasing a solar controller even tho they are not the cheapest supplier.

I would not use boatelectricals .co .uk ever ever again, poor customer service, no communication, took around 3 months to resolve and still they didn't get the order right.

 

6. I use a standard printer n paper to print off a label and then use clear heat shrink, I can then use a full description not just small codes or little info.

 

Edited December 22, 2016 by Robbo

[OldGoat]

If your fridge freezer uses a Danfoss compressor (and 'most' do) then the unit is / or is available in dual 12 / 24v configuration. The FF is the most power hungry low voltage device - so by running it in 12v mode there will be an imbalance in battery usage. So from both points of view 24V is better - you can also use thinner cable.

Having got thus far (if you agree) then why not wire the 12V sockets using a centre tap alternately? i.e 0-12v then 12v (centre tap on battery bank) - 24V. As long as the devices are separate from one another...... You also save on power converters

I dislike car type adaptors and used 3 pin 5amp plugs and sockets instead with 12V on earth and left hand pin, 24v earth and right hand pin. Terribly incorrect but as not many devices use 5amp P & S so there ought to be no problem.

 

When I built the boat the BSS was in a complete state of chaos, so I ran mains cable in domestic flat trunking under the gunnel and all services (lights, radio etc) in removable panels in the ceiling, both sides of the boat.

[Robbo]

I dislike car type adaptors and used 3 pin 5amp plugs and sockets instead with 12V on earth and left hand pin, 24v earth and right hand pin. Terribly incorrect but as not many devices use 5amp P & S so there ought to be no problem.

 

The 12v car sockets may not be the best, but they are very popular for 12v accessories and very handy to have around.

 

 

The CBE modular sockets (http://www.thecbecentre.co.uk/cbe-modular-system.html?cat=2261) may be worth looking at if your looking at multiple different type of sockets but want a unified look.

Edited December 22, 2016 by Robbo

[Chewbacka]

If your fridge freezer uses a Danfoss compressor (and 'most' do) then the unit is / or is available in dual 12 / 24v configuration. The FF is the most power hungry low voltage device - so by running it in 12v mode there will be an imbalance in battery usage. So from both points of view 24V is better - you can also use thinner cable.

Having got thus far (if you agree) then why not wire the 12V sockets using a centre tap alternately? i.e 0-12v then 12v (centre tap on battery bank) - 24V. As long as the devices are separate from one another...... You also save on power converters

I dislike car type adaptors and used 3 pin 5amp plugs and sockets instead with 12V on earth and left hand pin, 24v earth and right hand pin. Terribly incorrect but as not many devices use 5amp P & S so there ought to be no problem.

 

When I built the boat the BSS was in a complete state of chaos, so I ran mains cable in domestic flat trunking under the gunnel and all services (lights, radio etc) in removable panels in the ceiling, both sides of the boat.

I would NEVER centre tap from a battery bank.

 

Reason

After a long cruise without a centre tap both batteries are fully charged and so both at the same voltage - let's say 12.7V

Now apply a centre tap and lets take 5Amps (couple of phone chargers, lap top internet surfing for the evening, maybe a bit of 12v TV watching) After a few hours you could have taken 25Ahrs so if the batteries are 110AHr then you have dropped one battery by 25%SOC.

 

Now we start the engine to recharge and one battery is 75% charged whilst the other is 100% charged, but the charge current will be the same through both batteries as they are in series and being charged together, this will result in the full battery being constantly overcharged (damaged) with a real risk that the other battery will struggle to fully charge - again over a long time it will be degraded.

 

So all in all it may seem to work just fine, but you will be quietly shortening the life of your batteries.

For joining wires I have also found Wago connectors to be excellent and use them especially where I may wish to temp disconnect a circuit.

http://www.screwfix.com/p/5-way-lever-connector-222-series-pack-of-40/38224

[OldGoat]

Chewbacka, on 22 Dec 2016 - 3:15 PM, said:

I would NEVER centre tap from a battery bank.

 

Reason

After a long cruise without a centre tap both batteries are fully charged and so both at the same voltage - let's say 12.7V

Now apply a centre tap and lets take 5Amps (couple of phone chargers, lap top internet surfing for the evening, maybe a bit of 12v TV watching) After a few hours you could have taken 25Ahrs so if the batteries are 110AHr then you have dropped one battery by 25%SOC.

 

Now we start the engine to recharge and one battery is 75% charged whilst the other is 100% charged, but the charge current will be the same through both batteries as they are in series and being charged together, this will result in the full battery being constantly overcharged (damaged) with a real risk that the other battery will struggle to fully charge - again over a long time it will be degraded.

 

So all in all it may seem to work just fine, but you will be quietly shortening the life of your batteries.

For joining wires I have also found Wago connectors to be excellent and use them especially where I may wish to temp disconnect a circuit.

http://www.screwfix.com/p/5-way-lever-connector-222-series-pack-of-40/38224

Ah, yes,

BUT the OP said he was going to run a 12V fridge freezer from a 24V battery bank and didn't qualify how he was going to achieve that. (He mentioned voltage converters for low power devices only).

So, given an assumed imbalance - I tried to put a similar load on the other side. Provided that the user balances the loads on both taps, I don't see why not. I only have a water pump and a couple of lights unbalanced everything else is 24V or balanced in pairs.

 

 

My batteries are NiCds

[cereal tiller]

I would NEVER centre tap from a battery bank.

 

Reason

After a long cruise without a centre tap both batteries are fully charged and so both at the same voltage - let's say 12.7V

Now apply a centre tap and lets take 5Amps (couple of phone chargers, lap top internet surfing for the evening, maybe a bit of 12v TV watching) After a few hours you could have taken 25Ahrs so if the batteries are 110AHr then you have dropped one battery by 25%SOC.

 

Now we start the engine to recharge and one battery is 75% charged whilst the other is 100% charged, but the charge current will be the same through both batteries as they are in series and being charged together, this will result in the full battery being constantly overcharged (damaged) with a real risk that the other battery will struggle to fully charge - again over a long time it will be degraded.

 

So all in all it may seem to work just fine, but you will be quietly shortening the life of your batteries.

For joining wires I have also found Wago connectors to be excellent and use them especially where I may wish to temp disconnect a circuit.

http://www.screwfix.com/p/5-way-lever-connector-222-series-pack-of-40/38224

Agree with you re. centre tap for 12 Volt,it causes Chaos in the Universe!

 

24 to 12 Volt Dropper much better.

 

Those Wago connectors are V handy

 

CT

[Keith M]

I would suggest that the OP has look at two ISO 10133 and 13297

 

Another fan of Wago products

 

Centre tapping batteries is very poor practise

 

When using a DC to DC converter to run a fridge the power factor at start up is around 10 times the normal current for a second or two

 

Why not an AC fridge significantly better insulation than a DC model and great cost savings

 

Season's Greetings To All

 

Keith

Edited December 22, 2016 by Keith M

[Tom Richmond]

Ah, yes,

BUT the OP said he was going to run a 12V fridge freezer from a 24V battery bank and didn't qualify how he was going to achieve that. (He mentioned voltage converters for low power devices only).

So, given an assumed imbalance - I tried to put a similar load on the other side. Provided that the user balances the loads on both taps, I don't see why not. I only have a water pump and a couple of lights unbalanced everything else is 24V or balanced in pairs.

 

 

My batteries are NiCds

Sorry! Sorry! Sorry! 24v fridge...

 

Those Wago connectors look great!

 

Thanks for comments so far...

[system 4-50]

Wagos are the way to go.

[ditchcrawler]

I don't know how your power audit came out at 600 ah I have all that you are talking about and come out at about 30 ah on 24 volts. a bit more when we use the coffee maker. I also have a 1500 watt inverter on 24/7 for the 240 volt fridge.

[Tom Richmond]

I don't know how your power audit came out at 600 ah I have all that you are talking about and come out at about 30 ah on 24 volts. a bit more when we use the coffee maker. I also have a 1500 watt inverter on 24/7 for the 240 volt fridge.

Hmmm, yeah. 600ah battery bank at 12v! So only 300ah needed at 24v. This is the size of bank, so based on only 100ah of usage ( and that figure rounded up). The decision to go 24v is fairly recent, which is why my brain is still stuck in 12v. Excuse my mistakes.

 

Our heaviest use is computer charging. I am allowing for 3/4 hours per day for two laptops... But as I said, all quite preliminary.

[Guest]

Not seen those Wago's before. They look like a good idea.

[Tom and Bex]

Not much to add to the above replies but I would reiterate the advice to make it easy to run extra wiring/circuits in the future if needed. Wish I had done this on our boat. Might even be worth adding draw string in any conduits to make it easy to pull extra wires through.

 

Also (probably less of an issue on 24v) double check the voltage drop on your cable size calculations (particularly high current devices). Ours have turned out a bit marginal for the Webasto and water pump.

 

Finally, I noticed you mention shower sump pump. I world strongly advise you to scrap that idea and go with a whale gulper instead. If not you'll only be ripping the sump pump out and fitting a gulper in the future.

 

Tom

[ditchcrawler]

Not much to add to the above replies but I would reiterate the advice to make it easy to run extra wiring/circuits in the future if needed. Wish I had done this on our boat. Might even be worth adding draw string in any conduits to make it easy to pull extra wires through.

 

As my son said today, "why didn't you put LED colour changing strips under the gunwale?" Well they didn't exist when I wired the boat so there is no wiring in there for them. Likewise a USB outlet to charge the MiFi in the dog box. I would wire them if I was fitting today, but what will be needed in another 15 years, fibre optics?

[Tom Richmond]

As my son said today, "why didn't you put LED colour changing strips under the gunwale?" Well they didn't exist when I wired the boat so there is no wiring in there for them. Likewise a USB outlet to charge the MiFi in the dog box. I would wire them if I was fitting today, but what will be needed in another 15 years, fibre optics?

I work as a lighting designer for theatre, so have seen enough tacky colour changing lighting in my life. However, the point which is ability to change in the future is infinitely useful!

 

I am interested in the comments about USB C above, gonna do some extra reading now..

[Keith M]

Not much to add to the above replies but I would reiterate the advice to make it easy to run extra wiring/circuits in the future if needed. Wish I had done this on our boat. Might even be worth adding draw string in any conduits to make it easy to pull extra wires through.

 

Also (probably less of an issue on 24v) double check the voltage drop on your cable size calculations (particularly high current devices). Ours have turned out a bit marginal for the Webasto and water pump.

 

Finally, I noticed you mention shower sump pump. I world strongly advise you to scrap that idea and go with a whale gulper instead. If not you'll only be ripping the sump pump out and fitting a gulper in the future.

 

Tom

 

over the years I have installed many sump boxes

 

The main issue is the installer place them so that they can not be check or cleaned

 

Other wise my prefered choice

 

Season's Greetings

 

Keith

[Guest]

Not much to add to the above replies but I would reiterate the advice to make it easy to run extra wiring/circuits in the future if needed. Wish I had done this on our boat. Might even be worth adding draw string in any conduits to make it easy to pull extra wires through.

 

Also (probably less of an issue on 24v) double check the voltage drop on your cable size calculations (particularly high current devices). Ours have turned out a bit marginal for the Webasto and water pump.

 

Finally, I noticed you mention shower sump pump. I world strongly advise you to scrap that idea and go with a whale gulper instead. If not you'll only be ripping the sump pump out and fitting a gulper in the future.

 

Tom

Most definitely. Just fitted a Gulper on ours. Glad to see the back of the pump in a sump thing. Flooded the bilges a couple of times.

Edited December 22, 2016 by Guest

[ditchcrawler]

I work as a lighting designer for theatre, so have seen enough tacky colour changing lighting in my life. However, the point which is ability to change in the future is infinitely useful!

 

I am interested in the comments about USB C above, gonna do some extra reading now..

I wouldn't have used colour but white may have given some interesting lighting in the lounge area

 

over the years I have installed many sump boxes

 

The main issue is the installer place them so that they can not be check or cleaned

 

Other wise my prefered choice

 

Season's Greetings

 

Keith

This of course assumes the end user is going to take the trouble to check and clean them

[sharpness]

 

 

Why not an AC fridge significantly better insulation than a DC model and great cost savings

 

 

Is that right? I thought the 12v fridges were just 240v models with the compressor changed, the shell remains unchanged.

 

Steve

[ditchcrawler]

Is that right? I thought the 12v fridges were just 240v models with the compressor changed, the shell remains unchanged.

 

Steve

I think that.s right, a £100 LEC with a 12/24 volt compressor for £650 see http://narrowboatellis.blogspot.com/feeds/posts/default

[Tom and Bex]

 

over the years I have installed many sump boxes

 

The main issue is the installer place them so that they can not be check or cleaned

 

Other wise my prefered choice

 

Season's Greetings

 

Keith

That's the point, the whale gulper just keeps working year in year out - no checking or cleaning needed!

 

Ours was on the boat when we got it so of unknown age and has been working faultlessly for the past 6 years. Used on a daily basis as a liveaboard and never been touched let alone cleaned out.

 

Tom

Edited December 22, 2016 by Tom and Bex

[Chris-B]

I have to admit I would rip a sump box out and fit a Gulper 100% of the time

Whilst sump pumps do work well , I like many others forget to clean them and remove hair etc