Re-wiring madness...

[James W]

In my eagerness to sort out the wiring on the boat, the cabin is currently like spaghetti junction, except with cable ties, bits of wire and rusty chocolate box connectors. I've now learnt that like most things on a boat, if you don't want to be presented with a huge and expensive task, don't scratch the surface. In fact, if it aint broke, then step softly away!

Anyway, the problem I have is that on the starboard side is the original wiring which is beautiful and neatly run dual core, but it looks like it's been done with domestic cable and is probably due for a change. On the port side is a whole mish-mash of new single core, as messy as hell and wrapped in insulation tape.

Despite it's age (circa 1970's) the starboard side cabling all still works and runs the Nav lights, whilst the port cables carry the cabin lights, VHF and masthead light.

I'm definitely going to replace the single core but do you think it's best done with dual core or single core all together in some sort of trunking? I like the neat run of the dual core but is it too much? Also, whilst i'm at it, should I replace the original dual core or leave it until it gives up?

Does 1.5mm cable seem like a good all round size to minimise voltage drop for cabin lights? I was thinking of using 2.5mm for the masthead light.

And can anyone recommend a quality connector please? I want to keep the joins down to an absolute minimum but i'm sure they'll have to be the odd one.

Thanks as always!

James

 

[Keith-i]

If you plan to keep the boat long term I'd recommend using tinned cable and decent crimps for joints. Also, don't underestimate voltage drop on 12v circuits. Because the current is relatively high there are greater losses compared to 24v or higher. 1.5mm2 is a bit puny unless you're using led's. there are some good tables on the Ancor marine website about cable sizes for 3 or 10% voltage drop. Don't forget to measure the complete circuit from battery post to battery post when estimating circuit length.

 

[JSYmartini]

I quite like using single cores, they can look neat if you try.
Theoretically they're less bulky than multi cores as there's less sheathing involved.
Also you can use lots of different colours for different circuits rather than be stuck with loads of pairs of red and blacks so there easier to trace.

Another thing is that I've found that often on a circuit, the pos and negs don't often want to terminate at the same place, eg pos might go to the fuse box and the neg to a bus bar somewhere else. This makes it tricky for twin cores obviously.

Another vote here for Ancor tinned cable and their heat shrink terminals.
I get all my gear from this eBay store in the US:

www.stores.ebay.com/genuinedealz

 

[ShaunG]

Something like this

http://www.cablecraft.co.uk/protect/wrappasleeve.html
Or this
http://www.cablecraft.co.uk/grey-braided-sleeving.html

Can make single core cabling look very very neat (normally used in server rooms to keep network cables tidy, with a Velcro wrap at each end to keep in place)

I have used a similar product all round and it makes for a great looking, and easily added to job ( the second of the two links)

 

[LittleSister]

Anyway, the problem I have is that on the starboard side is the original wiring which is beautiful and neatly run dual core, but it looks like it's been done with domestic cable and is probably due for a change. ....

Despite it's age (circa 1970's) the starboard side cabling all still works and runs the Nav lights, whilst the port cables carry the cabin lights, VHF and masthead light.....

Also, whilst i'm at it, should I replace the original dual core or leave it until it gives up?

I don't understand why you would want to replace the 'beautiful, neat, dual core', or why it 'is probably due for a change', or the reference to 'until it gives up'.

It is very unlikely to 'give up'. If it's working why change it? There's nothing wrong with domestic cable except being untinned it will tend to accumulate verdigris (?) if it's exposed to damp, etc. Its capacity to conduct current will not be significantly changed. As far as I can see it just makes it harder to make a good joint, but if you're not changing the jointing that won't matter. Perhaps just inspect a sample of existing joints to make sure they're not being adversely affected by any corrosion. otherwise just concentrate on the bird's nest on the other side of the boat?

 

[James W]

Something like this

http://www.cablecraft.co.uk/protect/wrappasleeve.html

That looks perfect for the job, thanks Shaun.

But the question remains, should I start from scratch, removing all the original (if neat) 1970's wiring? It will certainly make for a neater, safer and more efficient job but it's a heck of a lot more work!

Thanks to all for the links to cheap cabling, very handy.

 

[davidpbo]

I would use tinned figure of 8 twin if available and the insulation is thick enough. No extra insulation pos and neg stay together, can be easily split if terminals are separate. Use coloured tape, numbers, coloured cable ties to mark if necessary.

If you use too thick a cable you may struggle to get it into some connectors.

 

[James W]

I don't understand why you would want to replace the 'beautiful, neat, dual core', or why it 'is probably due for a change', or the reference to 'until it gives up'.

It is very unlikely to 'give up'. If it's working why change it? There's nothing wrong with domestic cable except being untinned it will tend to accumulate verdigris (?) if it's exposed to damp, etc. Its capacity to conduct current will not be significantly changed. As far as I can see it just makes it harder to make a good joint, but if you're not changing the jointing that won't matter. Perhaps just inspect a sample of existing joints to make sure they're not being adversely affected by any corrosion. otherwise just concentrate on the bird's nest on the other side of the boat?

This is why I asked the question really, to get the thoughts of those more knowledgable as i'm no sparky. It looks pretty good to me so i'll do some closer inspection and check the joints.

The only real reason to change the original dual core (if there doesn't seem to be any problems), is that it doesn't have a full run to the battery and would have to be jointed with more cable.

 

[prv]

But the question remains, should I start from scratch, removing all the original (if neat) 1970's wiring? It will certainly make for a neater, safer and more efficient job but it's a heck of a lot more work!

Well, since it's you doing the work and not me, I say go ahead and remove it all

For what it's worth, I stripped every bit of wire out of mine. But I didn't have that much down below compared to a bigger boat, and I was moving several of the lights to better locations anyway (and adding new ones). I'd have needed to make a lot of joints at the panel end too if I'd kept the old. It was simpler to just strip the lot and start again.

You will use more wire than you expect to...

Pete

 

[James W]

Well, since it's you doing the work and not me, I say go ahead and remove it all

You will use more wire than you expect to...

Pete

Fantastic, more expense and work!

Isn't sailing just the best fun?!

 

[oldsaltoz]

I have had the pleasure and stress of wiring and rewiring several vessels over the years and find the most reliable and simple methods involve tinned single core cable, each with cable markers at the switch panel and a laminated schematic drawing, I also prefer installing circuit breakers rather than fuses.

LED lights are also high on the list of preferred items, less power, heat and much better life.

One yacht I wired when new about 18 years ago had the mast head globes soldered in place to avoid corrosion problems. it was replace a couple of years ago with a festoon LED and was still working fine when the mast was removed and new rigging installed.

The owner said he had not a single electrical problem with wiring in all that time and I did an inspection to how the main switch panel was looking.
I had sprayed it with a circuit board protection product made in France, designed to coat boards and protect them from corroding but allowing components to be removed and re soldered without contamination, sorry I don't remember the name.

No cable should be jointed but in some situations this is just unavoidable and using a resined heat shrink joint is the only way to do this, anything else is doomed to fail at some time.

Encasing cables is a simple task with the Anaconda type round plastic flexible conduit, it simply coils around the cables and allows for cables to exit or ender at any point. If you have any areas that a bunch of cables might be exposed, the 'U' shaped box conduit with a snap on cover looks very neat and makes for easy access to the cables at any point if required.

The advantage of doing a schematic drawing will also allow you work out the loads on each circuit and then install the correct size fuse or breaker, as well as what items are on any one circuit, you would not want to loose your radio and navigation aids if one fuse or breaker dropped out, nor would you want to have all the lights go dead at one time, doing a schematic can avoid many problems. as will keeping a laminated copy on board, I normally put on on the back of the panel and in the ships papers storage area.

Good luck and fair winds.

 

[john_morris_uk]

Encasing cables is a simple task with the Anaconda type round plastic flexible conduit, it simply coils around the cables and allows for cables to exit or ender at any point. If you have any areas that a bunch of cables might be exposed, the 'U' shaped box conduit with a snap on cover looks very neat and makes for easy access to the cables at any point if required.

I assume that you mean this sort of stuff:

http://www.amazon.co.uk/Outside-Diameter-Binding-Natural-Colour/dp/B0034R3NNM/ref=pd_sim_sbs_ce_5

It immediately came to mind to suggest this style of cable tidy when the OP said the multiple single core wires looked a mess on the starboard side.

Making a diagram, labelling the wires and getting the wiring to look neat and tidy is over half the battle. Good wires and well made crimped joints is nearly the other half. The actual electrical wiring and theory etc is a tiny part of the whole and although essential to get right isn't that difficult.

 

[David2452]

I've just finished an electrical refit on a 90 footer, 240ac, 12vdc & 12vdc, new everything including circuit breaker panels, consumer units, bus bars, sub panels, the lot, the largest one I've ever done and to be honest it's been a bit of a challenge (160m of AC cable alone), for what it's worth I'd use tinned single core except for long runs where the feed panel and return bus are close like mast nav lights and the like, single cable (ultra low voltage at any rate) is better than twin if not bundled too tightly as it has lower losses than tightly bundled stuff. Tinned copper un insulated terminals with separate covers are a good way to go as they make a good "ass cheek" roll over form which is very strong, avoid those red, blue, yellow auto crimps like the plague. I rarely do a schematic but always do a routing description, I identify the cables with printed heat shrink tube describing the function rather than using numbers and a separate chart now. try where possible to plan the job well before even starting, heavier single cable runs to smaller sub panels where possible saves time and is often easier for routing, work out the total load on the panel for the feed cable, not just for now but possible future additions where appropriate. Whether or not to start from scratch is a decision only you can make based on what you can see before you, but a blank canvas will give you a result you know will last if you are unsure about the state of the current install. Use the best quality consumables and crimping tool(s) you can afford. There is some good quality British made thin wall tinned cable around that is fairly reasonable if bought in bulk, you can always use it all with a bit of overkill on some circuits. A simpler and more accurate way to work out cable sizes which avoids the confusion of whether the table being used is based on round trip or simple distance from battery is 10.75 which is the constant assuming copper, times load amps, times round trip in feet, divide by the required volt drop (in volts) this gives the circular mil area which is easily convertible to AWG or mm2.

 

[doug748]

I think Littlesister has the right idea. Keep the original stuff, it will probably outlive you.

My boat is of an age, and it has single core, under grp, behind a grp lining. There would be no way of replacing it short of ripping the boat apart. I have every confidence in it.

 

[Richard10002]

When I had some wiring done on Rogue in 2006, the electrician used a multi core cable with about 8 different coloured wires in one case. This enabled him to wire 7 different things with one cable, using a common negative. It was very neat, and seemed very sensible.

Clearly, the negative base to be thick enough to carry the max current that might be drawn, and appropriately fused.

http://www.vehicle-wiring-products.eu/VWP-onlinestore/cable/multicorecable.php

Seems to cover a few bases?

 

[Boo2]

I identify the cables with printed heat shrink tube describing the function rather than using numbers and a separate chart now.

Interesting post, but how do you print onto heatshrink ?

Boo2

 

[JimC]

There's nothing wrong with domestic cable except being untinned it will tend to accumulate verdigris (?) if it's exposed to damp, etc. Its capacity to conduct current will not be significantly changed. As far as I can see it just makes it harder to make a good joint, but if you're not changing the jointing that won't matter. Perhaps just inspect a sample of existing joints to make sure they're not being adversely affected by any corrosion. otherwise just concentrate on the bird's nest on the other side of the boat?

I have used un-tinned cable, both domestic and automotive, I saturate the exposed copper strands and terminals etc with silicone spray and have not seen any corrosion, blackening or verdigris. The penetrative nature of the fluid means it coats all round every individual strand and penetrates under the insulation for a considerable distance.

 

[stephenh]

"How do you print onto heatshrink?"

Don't know - I usually print out on self adhesive sheet on the PC, cut out with scissors, apply to cable and then put clear heat shrink over, not the one with the adhesive.......

A good book on all things mentioned above especially design is Alastair Garrods book here -
http://www.ebay.co.uk/itm/ELECTRICS...0969306065?pt=Non_Fiction&hash=item19d6493bd1

Good luck

 

[ghostlymoron]

Whatever you do, keep a record and label the ends of each wire. Do a wiring diagram and as someone has already said, keep a laminated copy on board. Another tip not mentioned is to put draw cords in any ducting and through inaccessible areas so that you can pull extra cores through if (when) you add extra equipment.
FWIW I think that tinned cores are overkill below decks but well worth it above.

 

[James W]

I assume that you mean this sort of stuff:

http://www.amazon.co.uk/Outside-Diameter-Binding-Natural-Colour/dp/B0034R3NNM/ref=pd_sim_sbs_ce_5

Yes, and at a reasonable price too for once!

Thanks!