Boat wiring

[Bluefish]

Does the wiring in an aluminium boat need to be earhed in a particular way? Mine seems to be earthed to the hull.

[Oldyella]

Bluefish

That would be the most likely and constructive place to earth an Aluminum boat, as all electricals are mounted to the hull somewhere. A fibreglass boat needs to carry an earth wire from the battery to all the accessories or the fusebox for everything to work.

[drb]

Marine applications should not be earthed to the boat. This will introduce all sorts of problems with electrolosis not to mention the safety factor. Eg. Baot is used as the earth (negative side) and you have a broken positive wire (happens ofter in boats). This wire falls on the alloy deck, right next to that bit of fuel you just spilt.

KABOOM. [smiley=bomb.gif][smiley=angryfire.gif] [smiley=angryfire.gif] [smiley=angryfire.gif] [smiley=fireman.gif]

use a negative wire back to the battery or a bus bar. Do not wire it up like a car or we will be reading about you in the paper (hopefully not the obituaries)

[Volvo]

:)I'm with DazB on this one ey..

[dnej]

To true, and to be real correct, fit an isolation switch to shut off your battery completely, as needed.
Whatever you do, "no earthies on the tinnies pleassssse"
David

[familyman]

wire up your tinnie car style with a negative earth and next time you put it in the water you can watch it dissolve before your eyes(sarcasm)DO NOT DO THIS!!!

[Kerry]

ALL earths MUST run back to the negative side of the battery ONLY (alloy or whatever). The engine block is already earthed to the battery and that is it, no other earths to the hull anywhere.

Cheers, Kerry.

[NQCairns]

I am not enough of an electrical wiz to give an experienced answer.
The international guidelines state (or did state) to earth to the hull, I think it is the same reg that Quintrex use when they earth to the hull. I dont think there would be one maufacturer out there that wouldn't hull earth esp if exporting O/S. I didnt on purpose earth my tinney to the hull but understand that it is almost impossible to stop either the engine or some portion of it's mounting/wiring/cables etc from earthing the hull anyway.
Very grey area with general opinion contradicting International standards, buggered if I know.nq

[mini696]

I don't have an isolation switch installed yet, but will have once I finalise how I want to modify by tinnie. Its a must especially if you have radios (AM/FM) running off the battery. They will suck the power from your battery over a week or two (slowly but its enough).

I agree with the posts above. DO NOT earth to an aluminium hull.

[drb]

I would like to see these international standards nqcairns. Do you have a reference to these, a web url perhaps

thanks
Daz

[drb]

Ok found this. It is part of the USL Code which all surveyed vessels is Australia must comply with.

USL Code Section 9 Rule 27.2

plain as the nose on my face

[Needmorerum]

When I wired up my tinnie, I was advised to use marine grade wire as well, not just the normal copper wire that is used in cars. Good advice to, now that it is 12 months old, the wire on my little night light is buggered, where the marine wiring to my nav lights and sounder, is still spot on.
On the Quintrex's, my old man has a 5m Top Ender and all it's earths return to the battery, none of them is through the hull.

Corry

[drb]

Good point Corry. Insulated wire creates a capilary action that draws moisture up the insulation like a straw. After a while the wire corrodes and goes black and becomes brittle and breaks. Marine Wire is "tinned" which helps protect it against the corrosion. Another good idea is to solder all connections. Not completely necessary but will make a big difference in years to come.

[Bluefish]

Thanks for your replies. Will check wiring and look at the alternatives

[Aaron_Fogarty]

Keep all wiring isolated from the hull and run your main battery leads through an isolation switch. The cheap key turn one will do the trick.Also for tinnies, wires run under the gunnels rather than under the floor is the go. Ease of maintenance,Inspection,easy modificationsand less corrosion being the advantages. Also use a crimp style terminal on all connections not solder or the standard twist and tape. The vibration of boats crack solder joints and the t and t method, while ok at sea for a quick fix is not reliable and is prone to corrossion. spray all terminations reguarly with CRC this will ensure good reliable wiring.
Theres nothin worse jiggin a heap of good lookin slimies only to find out the pump dont work due to some half arsed wiring job. Wiring in new boats eg quintrex and stacers are sound (min requirements) A thing the 15 yo apprentice over looks is wire gauge. you have to match the current draw of all your acc. to the wire size many blokes add a hundred pumps and lights and dont think to change the main pwr wire. Aaron

[Payneful]

Aaron

Who told you that solder joints crack, I have never seen a good joint crack ??? ??? ???
IMO I believe that a soldered joint with heatshrink over the top would be better than a crimp any day.

Sam

[Kerry]

Aaron

Who told you that solder joints crack, I have never seen a good joint crack #??? ??? ???
IMO I believe that a soldered joint with heatshrink over the top would be better than a crimp any day.

There are things known as dry solder joints and dry solder joints may as well be "cracked" as they don't conduct and also just about every connection in an aircraft is "crimped" so think about that one :-X

Cheers, Kerry.

[aido]

i like a well soldered connection for splicing and joining
wires and crimps for terminal connections.

kerrys right about aircraft and crimps provide a good
connection which are almost foolproof in as much as
anyone can make a good crimp, and not many are good
with soldering (too many variables).
however, aircraft crimp terminals and those from automotive
and boat supplies are worlds apart in quality, not to mention
the tooling. i'm less than impressed with the end result of
hardware shop crimps and crimpers.

[Aaron_Fogarty]

Sam
Ive seen my share of cracked solder and dry joints in my time having worked as a marine and aircraft eleco over the last 12 years. Kerry is right about dry joints all soldered joints should be integrety checked with a multimeter. also the problem with heatshrink in a marine environment if it isnt environmentally sealed it breads corrossion and because its covered you only notice when something doesnt work. Good quality Tinned wire, the right gauge for the current draw, along with sound aluminium crimps covered with a thin film of crc. Youll rarely have a problem.......
regards Aaron

[aido]

hi aaron,
most crimp terminals, even hardware store quality ones
are unlikely to be aluminium. usually copper with a tin or
tin/lead plating is used.
not to say they don't exist, just used in special cases.
i've used special aluminium/copper splices on aircraft generator
feeders because the actual conductors are aluminium, just that
for copper conductors then standard copper crimps are used.
the big downfall with hardware quality crimping is the crappy tools used.
there is often less repeatability of a good joint than soldering them.
how many people crimp a wire into a lug only to have the wire fall out
and then recrimp it into an unsatisfactory mess. see it all the time.
also hardware quality crimps and tooling provide no strain relief for the
crimped connection and if they must be used, then i think crimping
and soldering might provide a more reliable low resistance connection.

[NQCairns]

G'Day Daz B sorry I have only just read the messages again, looks like I was wrong about the hull earth. If I remember right there was an interesting thread on a SPORTfishing site about a year or so ago about this exact same situation, might be worth a search?. I will chase up the regs I spoke of soon and see what transpires and get back to you. nq

[aido]

some very usefull info worth a read..

http://handbooks.camtronix.com/part1.pdf

[Aaron_Fogarty]

If the average bloke cant use a $20 pair of hardware crimpers to secure a wire to a terminal without it falling out then his forearms must be painted on.
Aaron

[Kerry]

If the average bloke cant use a $20 pair of hardware crimpers to secure a wire to a terminal without it falling out then his forearms must be painted on.

Ever seen the difference between hardware "style" wally market crimpers and crimps and the real thing?

Really similar can be said with heat shrink, there's the general run of the mill stuff then there's the good sealing stuff, costs more but doesn't all things.

Cheers, Kerry.

[gofishin]

It seems many are confusing 'earthing' the hull, and using the hull as an earth/current carrying conductor. The two are totally different, and the latter is a no-no.

If you have an engine on your tinny it is virtually impossible to isolate the hull from the 'earthed' motor. your hull will be earthed whether you like it or not!

run your negatives to the battery/negative bus. don't install electrical fittings (ie. cig lighters, some fuel gauges that are chasis grounded) to aluminium tanks/dashes that are part of/bolted to the hull, else your hull will become an earth carrying conductor.

The ABYC recommend earthing the hull of an aluminium boat. if my new boat doesn't come wired as such, it soom will be. unless there are electrical gurus out there that can scientifically prove this is bad, i will be taking their suggestion.

[NQCairns]

Gofishin where were you days ago, you would have saved me a long and fruitless internet search for those standards. Buggered if I could remember their name, I am sure most if not that all? manufacturers have to abide by these standards if exporting O/S. Still dont know why they are generally considered wrong.
Would like to read the specific standard if anyone can post it.nq

[ozz]

Hows it going. after reading this i thought i better look it up being an electrician i probably should know. What i found is that some manufatures earth the chassis to reduce the amount of wires (lazy). I wouldn't do it my self as it may cause corrosion to the hull. Its best to use a negitive bus on aluminium boats.

[gofishin]

NQ. There have been a few ding-dong battles on this subject over the years. you may remember a couple on sportsfish. one post had a scanned copy of a letter re ABYC & hull earthing, can't find it though.

[Kerry]

A "single" point of earth will always be the motor etc no way can this be avoided and there are things in place to counter this but in no way shape or form should there be a
"second" separate earth point from the battery to the hull.

So really it doesn't matter as there already is an earth as it will come earthed anyway BUT there absolutely does not need to be any separate earth, the engine is already it.

Cheers, Kerry.

[aido]

If the average bloke cant use a $20 pair of hardware crimpers to secure a wire to a terminal without it falling out then his forearms must be painted on.
Aaron

the average bloke probably can't strip a wire properly before
even getting the crimps out, #:o.

http://users.tpg.com.au/adessaix/crimper2.jpg
these are good crimpers, ratchet controlled to ensure repeatable uniform crimping
and adjustable secondary crimping onto the insulation to provide strain relief.


http://users.tpg.com.au/adessaix/crimper3.jpg
these crimpers are not worth pi$$ing on,
do more damage than good.

somewhere in between these good and bad crimpers are a
set worth about $40 and they are average quality but like
any tool, always get the best you can afford.
i notice see-saw had a failure his last trip out took out
everything except the motor, maybe a bad crimp mate??

happy crimping, aido.

[Payneful]

Kerry and Aaron

I haven't read this post for a while but I have had serveral experiences with crimps that have failed. I think the main reason crimps are used is to save TIME. A properly heatshrunk soldered joint takes about 10 times longer in my experience.

When submersible pumps are installed that are going to spend the rest of their live UNDER water, guess how they splice the cables? Soldered with heatshink over the top. (admittedly they use adhesive lined heatshrink)

In my opinion the failure rate of crimps when compared to soldered joints is about
I recently had the stator replaced in my outboard and after taking the boat out a couple of times the tacho started playing up, being electrically minded i went in search of the problem. Alas ... failed crimp (and this was done "professionally). I have replaced it and the other dodgy ones with a soldered and heatshrunk joint ... and no more problems since (i do use adhesive lined heatshrink).

Just a thought, would you rely on a crimp a connection to a bilge pump that is going to lie in the bilge i.e. salty water?

Sam

[aido]

good example payneful,
perhaps the crimp AND solder is the go.
at least the crimp will steady the wire and lessen
the chance of a dreaded dry joint.
on soldering, the most imprtant thing is CLEAN, then
heat and flux flow. then we have a fine soldered joint
that will outlive a crimp ten times over.
the tin/lead fusion ensures that.

[dfox]

Been reading this debate with interest, personally i solder and heatshrink and have vertually no problems, of cause i only use tinned wire, my question is what type of wire do they use in aircraft when crimping?...foxy

[Payneful]

Foxy

All aircraft wire is tinned.

Sam.

[NeilD]

We have a cruising boat so our bilge pump connections live in a pretty hostile environment. A crimped join would not last IMHO when compared to a well soldered joint. We also use either the fusing heat shrink or liquid electrical tape if the wires are clean.

Neil

[Aaron_Fogarty]

Gentleman Jet aircraft use crimps throughout their wireing where possible. All splices where nessesary are crimped then envomentally sealed. Engineers at work have thrown around different ideas but the crimp is still the money for durability and strength!

A crimp is stonger and more duable than any blob of solder and of course any thing sealed properly (environmentally ) is not going to corode.
Enjoying the constructive debate
Regards Aaron

[NeilD]

Aaron
What do you mean by sealed properly (environmentally)? I would have considered a properly soldered joint in tinned wire to be a strong joint both in terms of mechanical force and corrosion resistance.
Where do we get these aircraft crimps to look at? I would think that a boat bilge is a considerably more corrosive environment than a well maintained jet aircraft so perhaps they would have to be sealed well.

Neil

[aido]

i usually keep a variety of splices on hand.. ;D

http://users.tpg.com.au/adessaix/splice1.jpg
here's an aircraft enviromental butt splice (raychem),
stripped wire is inserted into the metal barrel and crimped
with special crimpers (definately not hardware crimpers).
the sleeve is heat shrunk over the finished crimp which
seals and provides some strain relief for the wire joint.


http://users.tpg.com.au/adessaix/splice2.jpg
this is a standard aircraft butt splice (amp), it is not
environmentally sealed but using the correct crimpers
crimps the wire conductor and also the insulation to provide
strain relief. a general purpose crimp used in most situations.


http://users.tpg.com.au/adessaix/splice3.jpg
here is the general purpose hardware crimp found in auto and
boat supply stores as well as hardware shops. you can't see
the wire depth to assure correct crimping nor does it provide
for strain relief of the finished joint. you can use hardware
crimpers on it though to ensure a dubious connection at best.
i would prefer soldering anyday than using this crimp.

[nofrills]

i think its tops the high standard of replys that keep coming up in the boating chat section,and by people who obviously know their stuff.only thing is i keep finding out that the great job i thought i did last week is up the gary ::)

[Heath]

Luckly my Cruisecraft uses them aircraft butt splices [smiley=2thumbsup.gif]

If I do any work myself, I solder the joint, then give a good coating with liquide electrical tape & then finally heat shrink with internal adhesive.

Have never had a joint fail.

One of the most shocking setups I've seen was on a mates Formosa Center Console, the crimps were them El' Cheapo ones, the worst thing was is that they were not covered in any way, were left hanging loosly on the aluminium tray at the back & finally they were for the under floor bilge. Slightest bit of water & poof!

[SeaSaw]

Great information guys. Now where do us non-aircraft techos get these butt splices. Are they available from electrical supply shops? I've never seen them in auto shops. ???

Thanks,

Mark

[aido]

jaycar electronics sells a range of lugs and splices
that seem to be of reasonable quality and have
the heat shrink self sealing feature.
they also sell the standard types to be avoided

[gofishin]

...but in no way shape or form should there be a "second" separate earth point from the battery to the hull.

Cheers, Kerry.


Kerry, why? I am a convert for a hull earth (NOT wired like a car or using it as an earth carrying conductor, just a good earth, -ve run separately to battery) because of personal experience, and from reading other literature incl ABYC. I am not an electrical guru by any means, but am interested in your/others opinion(s).

A few years ago I had a custom tiller steer tinnie with all the bells and a rectifier/charging circuit on the Merc. Had a sounder mounted on a v.small side console with multiple switches running pumps, lights etc, with fuses!. The hull was not separetly earthed. Motor (ML40) had a small (~16g) sheathed earth strap(?) b/w motor & transom bracket.

One day in the garage after turning on the battery switch i heard a slight hissing/sizzling to find smoke coming off this 'strap' & the plastic part very hot! somewhere i had a +ve short to the motor/hull!

The motor was providing a weak (high resistance) earth, enabling the closed circuit, however like every outboard, it was on a plastic backing plate, with lots of silicon around/between the bolts etc. The 'weak' earth was allowing a trickle current through, but not enough to blow a 5A fuse etc.

I couldn't find the problem, my dealer could not find the problem (replaced some wires in the motor!!), but separetly earthed the hull with the explanation that a 'good' earth will always mean you blow your fuse & not slowly cook something else/motor electrics due to the poor motor/hull earth - high resistance low current.

Logic made sense to me!

So why not?

[Aaron_Fogarty]

What do you mean by sealed properly (environmentally)? I would have considered a properly soldered joint in tinned wire to be a strong joint both in terms of mechanical force and corrosion resistance.????????
HORSE
environmentally sealed means their is an outer protective cover, usually plastic or rubber that prevents the ingress of anything foriegn including air (corrosive salt air)
Solder is not an environmental seal and even good quality tinned wire corrodes, usually under the wires insulation...Salt water is an awsome corrossive although I think coke a cola is better...ha ha

Aido is on the money with his great pictures,those Raychem crimps are the ones we use at work. when the outer insulation is melted with a heat gun the ends become moulten plastic and form an environmental seal.
For the average bloke though the good quality auto crimps are ok I ve used them before and seal each side with a little salastic or sickaflex.
Happy crimping gents!!!!
regards Aaron

[NeilD]

I will certainly check out these quality crimps. I already have a farly good rachet type crimper so it should do the job. I'm still not fully convinced that the joint will be better than solder and liquid electrical tape but it will be a lot faster and easier.

Neil

[Kerry]

Kerry, why? #I am a convert for a hull earth (NOT wired like a car or using it as an earth carrying conductor, just a good earth, -ve run separately to battery) because of personal experience, and from reading other literature incl ABYC. #I am not an electrical guru by any means, but am interested in your/others opinion(s).

Logic made sense to me!

So why not?


That logic to me says if your still blowing fuses (rather than sizzling) then there's something amiss and tends to indicate an excuse rather than actually fixing the "real" problem.

As for the ABYC, lets hope there's no misunderstanding between the requirments of 12 volt systems and 240 volt systems, earthing is rather totally a different issue.

As I understand things specifically earthing the battery -ve to the hull creates a earth that has a different potential than the earth cable between the battery -ve and the outboard (block etc). There is no way the potential can be absolutely the same hence creating a route for current to run around the hull. Marina's can be extremely bad for this type of issue just with different types of boats, pylons etc with different types of potentials not even connected but in close proximity. The path of least resistance and if there's no path then there's no problem. Additional hull earth creates additional paths and exit/entry points.

Cheers, Kerry.

[NeilD]

Kerry
We have had some major problems in marinas, especially with close proximity to larger steel boats. After one slipping we actually found surface corrosion of our timber hull in very fancy patterns near some bronze fittings. strangely enough the anodes were still intact.