Marine Cables vs Land Based Ones

There is no difference in the wire itself per se, the codes governing wire usage are specific to the circumstances, environmental and otherwise, that the conductor is to be used in and for...

I am not aware of anything fancy regarding the differences between marine and standard cables apart from the fact the insulating sheath may be of a different material (or have a different level of protection) and has been tested differently (industrial cables don't need to tested and approved for deep submersion or salt rated for example).

As for lower weight and tighter bend radius, again it depends on the cable insulation (and to some extent cable stranding).

Given these tighter specification for marine cables, I hope that marine cables can be used in land based application and not vice versa.

I see no reason why not (as long as the cable meets the specifications you require).

Sometimes you don't have a choice and need to use marine-rated cables - for example there are highly flexible cables called 'trailing cables' designed for marine reeling applications (such as those on marine cranes), but they are fine to use in industrial applications. I would have used them but it was cheaper to have a production of a couple of km's of custom specified cable made for a project requiring highly flexible screened HV cable.

Only a suggestion : look at approved / recommended current magnitude since it could be different due to the different cooling capacities in water and air. However the thickness of insulation are as well different so that could compensate.

Engineer in the making, you have been given some good answers but I wonder if it is really clear why they are good. The distinction is mainly in the insulation. The insulation temperature rationg has to be 105c and the insulation has to be oil and fuel resistant. The wire must be stranded as Class 3, nothing less in order to with stand constant engine vibration.. Depending on service use the cable must be more abrasion resistant because the constant vibration causes chafe. Commercial ship grade has to be rated as low smoke in event of fire and is often sheathed in a copper mesh not only for abrasion resistance but also Rf shielding.

For commercial ship power systems the insulation is often very high voltage such as is found in diesel electric applications using a thousand volts or more. House insulation can often get away with 300 V or at worst 600 volts.

For cable sizes over 2/0 I find locomotive cables serve nicely and their spec exceeds ABYC standards.

Last but not least, marine grade cables have insulation that withstands immesion better than regular outdoor grade. However if you know it is going to get wet periodicaqlly consider going with submerged cable rating. I have found as little as 18 months of boat use may degrade the insulationb enough that it fails a megger test and sometimes cause tripping in a GFCI circuit.

If you find marine cables lighter in weight, its likely because ship board cable often do not have a concentric neutral jacket like we use in power stations.This has more to do with how over current protection and fault detection is done in land based power stations compared to shipboard use.

I worked as a protection and control technician for a big power utility and later became a certified marine electrician. My comments are based on usage and observation rather than an engineering degree.

FYI: Eng in the Making, most ships are built to a marine standard, this standard tells you what cable you can use and can't use. Loyds underwrite a large porportion of the ships in the world, they would never underwrite a ship that did not have used marine cable.

Cheers

Joe

We're still not being told what the question is, this happens so many times with these sites, someone asks a question but doesn't elaborate on the actual meaning of said question, we still don't know whether we are being asked about marine installations or sub-sea.

Bazzer

I'm guessing that by marine you mean submarine cables, as a submarine cable the heat will dissipate through the water and stay more or less at a constant temperature. Unless of course you are talking about marine as in yacht or boat hook up at the marina then the outer sheath has to be able to cope with salt water.

Bazzer

Overall, good answers to your post. From your query, I assumed you were asking about SUBmarine cable. Based on a couple of the replies, you might want to clarify if you are refering to cable for marine, ocean vessel use, or submarine, underwater use.

I have had occasion to work with a couple of types of movable bridges and have run into extra flexible, multi-conductor, submarine cable being specified for river crossings. Thats why some bridges prohibit the use of anchors in the immediate vacinity, so the cable does not get snagged and damaged by the anchor.

As already been indicated, marine cable is not an appropriate term to be used here. It should be either marine shipboard cable or submarine (or subsea) cable.

Submarine (or Subsea) cable characteristics:

Subsea cables must be resistant to corrosion and abrasion caused by sea currents, waves as well as human and vegetation attack. It also must be capable of offering a maximum of efficiency over long distances.

Shipboard cable characteristics:

Shipboard cable must be soft annealed, flexible stranded (greater than Class B), tinned copper conductors, cross-linked polyolefin (XLPO) or cross-linked polyethelene (XLPE) insulation, flame retardant or fire resistant, oil, sunlight, moisture and abrasion resistant thermoset jacket, and basket weave wire armor or continuous corrugated armor with outer thermoset sheath, low smoke halogen free.

- MS