CCA cable

[Hairy Animal]

Does anyone know if there's anything in the BSSC rules, or any other good reason not to use, CCA (copper clad aluminium) cable for non safety-critical applications in our boat?

 

So far as I can see, a particular cable of size 2mm² with 50/50 Cu/CCA strands and a 25A rating, should be ideal for a battery charging application (14A max.) and somewhat cheaper than 100% copper.

[by'eck]

I understand its more prone to fracture than plain copper which must be multi-strand anyway. Its less conductive than copper and more prone to corrosion. Consequently probably not ideal for a boat.

[nicknorman]

For BSS Al is not an issue. For building to the RCD, ISO 10133 requires copper.

 

Al has roughly twice the resistance of copper, so you need much more area to get the same voltage drop. For 12v DC systems voltage drop is normally the limiting design criteria so you would need much fatter cables to achieve the same thing. With boats, space for routing cables is often an issue. Al is less tolerant of mechanical stress although if you increase the CSA to match the equivalent resistance of copper they are similar.

 

Overall I would stick with copper since, in the context of a boat, the cost of wiring is not great.

[Loafer]

While you're on, Nick, I once heard a boatyard expert mentioning 'DC cable'. What is that, exactly? Is it just multi strand copper to prevent stress fracture?

[MtB]

While you're on, Nick, I once heard a boatyard expert mentioning 'DC cable'. What is that, exactly? Is it just multi strand copper to prevent stress fracture?

 

 

Anyone claiming to be an 'expert' generally isn't. The more you get to know about a subject, the more you realise you don't know. Anyone claiming to be an 'expert' generally isn't, as they have yet to understand how much they don't know.

[nicknorman]

While you're on, Nick, I once heard a boatyard expert mentioning 'DC cable'. What is that, exactly? Is it just multi strand copper to prevent stress fracture?

Sorry, not heard that term. Obviously there is no fundamental difference between cable used for DC vs AC, well except for the insulator colour perhaps!

[MtB]

While you're on, Nick, I once heard a boatyard expert mentioning 'DC cable'. What is that, exactly? Is it just multi strand copper to prevent stress fracture?

 

 

Actually that's an easy one to answer.

 

DC cable has red and black insulation, AC has brown and blue.

 

Sorted!!

[Alan de Enfield]

Not heard the term 'DC Cable' before but 12v DC automotive cable manufactured to BS6862 has a different construction to 'mains' cable to BS6500.

 

Both are PVC insulated 'flexible' stranded conductors but conductor make up and, in some instances, have differing insulation thicknesses.

 

As an example : 1mm² single core automotive 12v cable to BS6862 will be 14/0.30mm (14 strands of copper, each of 0.3mm diameter) whilst the 'mains' flexible to BS6500 will be 32/0.20mm (32 strands of copper, each strand being 0.2mm diameter)

 

(ISO & EN specs now equivalent)

[Tony Brooks]

Nowadays the readily available "automotive" 1 sq mm CSA cable is also 32/0.20 so it complies with the "minimum number of strands" standard and thus the RCD.

[cuthound]

Sorry, not heard that term. Obviously there is no fundamental difference between cable used for DC vs AC, well except for the insulator colour perhaps!

And it's insulating properties. Don't think I would trust a cable designed for say 50 volts DC on a 415 volt installation.

 

Edited for spullong.

 

 

Actually that's an easy one to answer.

 

DC cable has red and black insulation, AC has brown and blue.

 

Sorted!!

You must be younger than you look Mike, if you don't remember the red, black and green domestic Maine cabling prior to (I think) 1977. Edited March 10, 2016 by cuthound

[Alan de Enfield]

 

Nowadays the readily available "automotive" 1 sq mm CSA cable is also 32/0.20 so it complies with the "minimum number of strands" standard and thus the RCD.

 

Good to know.

 

Maybe the "DC Cable" comment was referring to the cables sold as '"marine cables" (by such as ASAP Supplies) where they state :

 

"Maximum voltage 60v, suitable for 12v and 24v systems, manufactured to ISO6722Part 4 : 1993 (class B)"

Edited March 10, 2016 by Alan de Enfield

[nicknorman]

And it's insulating properties. Don't think I would trust a cable designed for say 50 volts DC on a 415 volt installation.

Edited for spullong.

 

Sure but a cable for high voltage DC would be the same as one for high voltage AC. It would be a mistake to presume that DC is always low voltage and AC always high voltage.

[cuthound]

Sure but a cable for high voltage DC would be the same as one for high voltage AC. It would be a mistake to presume that DC is always low voltage and AC always high voltage.

True, I gave been involved with many 400 volt DC UPS installations, however we were talking in inland marine terms, where the highest voltage I have seen was a 72 volt DC hybrid drive motor.

[Tony Brooks]

Good to know.

 

Maybe the "DC Cable" comment was referring to the cables sold as '"marine cables" (by such as ASAP Supplies) where they state :

 

"Maximum voltage 60v, suitable for 12v and 24v systems, manufactured to ISO6722Part 4 : 1993 (class B)"

 

If a cable is being sold as "marine" then it should have tinned conductors to minimise corrosions where as "automotive" cable normally has plain copper conductors. Fir inland use plain copper conductors seem to last well enough for most people but if you wanted the best job tinned conductor cables would be the thing to use.

 

I few years ago I got a question from a Cornish fisherman who was having endless problems with bilge pump wiring corroding and breaking. It turned out that he was using plain copper conductors. I told him to use tinned and have heard no more. Draw your own conclusions. I use automotive cables on my own boat but always leave a bit of slack for cutting back later.

 

 

 

 

[BruceinSanity]

This where it's a shame that gold has a bizarre status in commerce. Think what an ideal conductor it would make if its value wasn't artificially inflated by burying most of what's been dug up.

[by'eck]

This where it's a shame that gold has a bizarre status in commerce. Think what an ideal conductor it would make if its value wasn't artificially inflated by burying most of what's been dug up.

 

Actually gold is not as electrically conductive as copper. Its used to plate high end electrical contacts because its inert properties prevent corrosion.

[DHutch]

Overall I would stick with copper since, in the context of a boat, the cost of wiring is not great.

 

I think I would also steer clear, life is too short to deal with the consequence of such risks. Perhaps the only place I would considered it was if I where running heavy duty cables up to the bow for a thruster and could arrange it so the cable could be changed if needed. That said, if doing that an money was tight I think I would used second hand welding earth cable rather than new copper-aluminium.

[DHutch]

Not heard the term 'DC Cable' before but 12v DC automotive cable manufactured to BS6862 has a different construction to 'mains' cable to BS6500.

 

Both are PVC insulated 'flexible' stranded conductors but conductor make up and, in some instances, have differing insulation thicknesses.

 

As an example : 1mm² single core automotive 12v cable to BS6862 will be 14/0.30mm (14 strands of copper, each of 0.3mm diameter) whilst the 'mains' flexible to BS6500 will be 32/0.20mm (32 strands of copper, each strand being 0.2mm diameter)

 

(ISO & EN specs now equivalent)

 

Interesting.

 

The wiring on our boat (I have photos as am about to make some changes and add some more) appears to be made to bi/tri-rated cable, to BS6231 and CSA-TEW.

 

I dont know how BS6231 compares to BS6862 or BS6500?

 

 

Daniel

[Alan de Enfield]

 

Interesting.

 

The wiring on our boat (I have photos as am about to make some changes and add some more) appears to be made to bi/tri-rated cable, to BS6231 and CSA-TEW.

 

I dont know how BS6231 compares to BS6862 or BS6500?

 

 

Daniel

 

BS6500 is the 'mains' voltage specification for 300v insulation thickness (rated at 300v between cores and 500v between core and sheath)

BS6231 is rated at 600/1000v (600v between cores and 100v between core and sheath)

 

Basically the difference is insulation thickness.

 

CSA is Canadian Standards Authority,

 

Tr-Rated cable is one where the same piece of 'wire' meets the standards of BS, CSA and UL (Underwiters Laboratories - the American Test house)

Edited March 10, 2016 by Alan de Enfield

[BruceinSanity]

Actually gold is not as electrically conductive as copper. Its used to plate high end electrical contacts because its inert properties prevent corrosion.

Thanks for that, I'd always assumed (no idea why) it would be more conductive!

[Hairy Animal]

must be younger than you look Mike, if you don't remember the red, black and green domestic Maine cabling prior to (I think) 1977.

Not only do I remember red/black/green mains cables, but also the stackable Wylex plugs (central circular earth pin with rectangular live/neutral pins in line either side). And of course the 3-pin 5A plugs and larger 3-pin 15A plugs.

[ditchcrawler]

Not only do I remember red/black/green mains cables, but also the stackable Wylex plugs (central circular earth pin with rectangular live/neutral pins in line either side). And of course the 3-pin 5A plugs and larger 3-pin 15A plugs.

Same here

[Loafer]

Interesting stuff. So DC cable is a load of old bollocks then. Just cable that's suitable for vibration resistance, insulation suitable for about 50V, and thick enough to pass the required current.

 

Sorted, ta.

[DHutch]

BS6500 is the 'mains' voltage specification for 300v insulation thickness (rated at 300v between cores and 500v between core and sheath)

BS6231 is rated at 600/1000v (600v between cores and 100v between core and sheath)

 

Basically the difference is insulation thickness....

 

Right, so in short, either is more than enough for a 24vdc installation. Likely out boat used BS6231 simply as that's what was offered and or available at the right price at the right time.

 

I understand that 'bi-rate' or 'tri-rated' simply means the cable complies with more than one countries standards simultaneously.

 

Daniel

[Chewbacka]

 

Right, so in short, either is more than enough for a 24vdc installation. Likely out boat used BS6231 simply as that's what was offered and or available at the right price at the right time.

 

I understand that 'bi-rate' or 'tri-rated' simply means the cable complies with more than one countries standards simultaneously.

 

Daniel

I bought my Tri-Rated cable from these people

http://www.csecables.com/acatalog/Tri-Rated-Cable.html

a lot cheaper than by the meter from a chandlers.

It is not tinned, but if you use good crimps and (optional) heatshrink then I doubt you will have problems on fresh water.

 

You are correct in that Tri-Rated complies with UL (USA), CSA (Canada) and BS (UK).