Suitable sheath materials for battery cables

[Jammer]

I am reviewing the battery cables and DC busswork on my boat. Like many vessels of its age, the manufacturer-provided cabling does not fully comply with current ABYC standards.


I am planning on adding Class T fuses. Since it is not ordinarily feasible to place these within 7" of the battery terminal, ABYC compliance requires that the battery cable be inside a sheath or enclosure.


What sort of materials are commonly used to comply with this requirement, given the need for flexibility and the need to avoid using anything that will trap heat? I've seen a number of mesh-type products out there -- are these good enough?

[noelex 77]

Originally Posted by Jammer

I am planning on adding Class T fuses. Since it is not ordinarily feasible to place these within 7" of the battery terminal

If you have room and reasonable access to the top of the batteries, you can add a T class fuse directly to each battery using a short copper busbar to connect to the battery terminal. The video linked below illustrates this. An alternative is to use MRBF fuses, but these have a much lower interrupt current limit. This solves the need for conduit and is safer.

https://youtu.be/2r6NbG73qZg?si=E1JKoUD6hkhb0sOv

[Statistical]

Split loom plastic is usually used. I don't think ABYC defines sheath anywhere. It will lead to some heat retention.

I am a big fan of Class T fuses but if you can't install them close to the battery and your batteries are 12V and either non-lithium or relatively small I would go with MRBF. On smaller 12V systems I would say MRBF on the terminal beats class T fuse 4 feet down the wire. Sheaths aren't foolproof. They reduce the chance for wire damage or chafe but it can still happen and the fuse can't protect from a dead short between the fuse and the battery.

[GordMay]

Battery cables, which are sheathed, can have the OCP as much as 72" [183cm] away [but, as close as practicable to the battery]; if the conductor is connected directly to the battery terminal, and is contained throughout its entire distance, in a sheath, or enclosure, such as a conduit, junction box, control box, or enclosed panel.

As Statistical noted, I don’t think ABYC defines “sheath” characteristics; but, as you [& BSS*] note: cable sheaths [looms/sleeves] “can reduce the cooling and reduce the safe capacity of the wire.”


* “ABYC Excerpts” ~ by Blue Sea Systems [BSS]
➥ http://assets.bluesea.com/files/reso...YCexcerpts.pdf

Originally Posted by BSS

“...
Wire selection for DC applications on boats is usually based on voltage drop requirements. However, there is a maximum continuous current that the wire can withstand without overheating. Higher grade marine wires are rated for service up to 105°C (221°F)—the ABYC wire capacity table for 105°C is most frequently quoted.
Table VI-A accurately reflects the capacity of single conductors exposed to freely circulating cooling air.
However, other factors, such as covering bundles of wire in outer jackets to form a cable, or use of conduits or structural voids to protect wires, can reduce the cooling and reduce the safe capacity of the wire.
Tables VI-B, C, and D take into account sheathing and bundling of conductors which reduces the available capacity to carry current without over heating.
A more conservative strategy is to use the 105°C wire, but treat it according to the 75°C column when selecting circuit protection unless the wire is openly exposed for cooling. ...”

See also, Fishspearit’s post ➥ https://www.cruisersforum.com/forums...ml#post3755796
In “ABYC definition of conduit” ➥ https://www.cruisersforum.com/forums...it-273946.html

[Hartleyg]

Hi Jammer,


I've always viewed the "sheath" requirement as an additional layer to warn you of a chafe situation - that is, it will show you where chafe is occurring without impinging the conductor insulation.
I've used this stuff: https://www.amazon.com/Alex-Tech-10f...7FVZLCQY/?th=1 - it comes in a couple colors, is easy to install and seems fairly rugged.


Hartley
S/V Atsa

[dannc]

I just happened to watch one of Jeff Cote's video from https://www.pysystems.ca/resources/videos/ about wiring conduit.

One of the interesting things he said was to be aware that one can get condensation, or one can have a leak, that leads to water pooling in low spots in conduit. Mesh conduit prevents this from happening. This was the video, https://www.pysystems.ca/resources/v...es-on-my-boat/

[jcapo]

From E-11 2008:

11.4.24 Sheath - A material used as a continuous protective covering, such as overlapping electrical tape,
woven sleeving, molded rubber, molded plastic, loom, or flexible tubing, around one or more insulated
conductors.

Anyone have this definition from a current E-11?

I used woven sheath because my fuses are a bit more 7" from the battery post depending on what is measured, wire or bolt to bolt. Overkill but I wanted to be compliant for my next insurance survey.

[Statistical]

Originally Posted by jcapo

From E-11 2008:

11.4.24 Sheath - A material used as a continuous protective covering, such as overlapping electrical tape,
woven sleeving, molded rubber, molded plastic, loom, or flexible tubing, around one or more insulated
conductors.

Anyone have this definition from a current E-11?

I used woven sheath because my fuses are a bit more 7" from the battery post depending on what is measured, wire or bolt to bolt. Overkill but I wanted to be compliant for my next insurance survey.

It is the same definition in 2023 version just number has changed due to additions.

11.4.32 Sheath - a material used as a continuous protective covering, such as overlapping electrical tape, woven sleeving, molded rubber, molded plastic, loom, or flexible tubing, around one or more insulated conductors.

[Wayne Gilham]

Be sure the sheath is fire-proof. Though inexpensive and readily available, the corrugated plastic sheath material from Harbor Freight DOES "catch on fire" and supports flame (I personally tested it, in my prior work as SAMS surveyor). Here's a case where using the more-expensive Ancor product is definitely advised (again by personal test, it cannot ignite - it will melt, but does not support flame). By similar personal test, Plastic soda-pop bottles (Pepsi, Coke, etc) will not support flame, and thus are excellent for making battery terminal boots in any shape you need -- holes for plastic wire-ties to keep them on can be easily made with office paper-punch. (Ancor ones and others at West Marine etc do not properly cover cables coming from different directions.)

[scherzoja]

Here are some choices for fire-retardant split loom and expandable sleeving


https://www.mcmaster.com/products/lo...ated-sleeving/

https://www.delcity.net/store/Flame-...-Loom/p_811448

https://www.delcity.net/store/High!T...-Loom/p_811350

https://www.delcity.net/store/Flame-...06793.h_806794

https://www.mcmaster.com/products/lo...le-sleeving-7/