[PSUBS-MAILIST] Wire type for submersibles

[Alan via Personal_Submersibles]

Hi Brian, 
ABS in section 10 electrical systems, 17.1 says cables & wiring within the
pressure boundary are to be low smoke, low/zero halogen cables.
So PVC is out according to them.
But don't shoot the messenger; if your PVC isn't packed in tight next to
some electronics then there probably isn't much chance of it catching fire.
Also if you have an extinguisher & a regulator on board you have back ups.
Part of the reason they don't like halogens is because of the acidic smoke that 
can kill sensitive electronics. This would be more of an issue in a military
sub than a home built psub! Good to be aware of this stuff though!
Alan


Sent from my iPad

> On 21/05/2017, at 7:27 PM, Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Alan,    Is PVC a no no for all types of PVC ?  with American Bureau of Shipping as well ?   What about PVC pipe ?
>  
> Brian
> 
> --- personal_submersibles at psubs.org wrote:
> 
> From: Alan James via Personal_Submersibles <personal_submersibles at psubs.org>
> To: "psubs.org" <personal_submersibles at psubs.org>
> Subject: [PSUBS-MAILIST] Wire type for submersibles
> Date: Sun, 21 May 2017 05:44:28 +0000 (UTC)
> 
> This is a summary of what I have been researching on wires.
> Steve wanted to hear this, but I would appreciate any other words of wisdom on this subject.
>    As a generalization G.L. says protective coverings, sleeves, sheaths & fillers are to be
> made of halogen free materials. This is because they are toxic & acidic when burning.
> PVC has halogens in it, & it is a common insulation on marine grade wire! Also PTFE
> (Teflon) insulation has halogens. Subconn connectors have PTFE wire insulation that runs
> in to the hull.
> In my view the halogen content won't matter if the wire is outside the hull. G.L. does say that materials
> & insulations for electrical equipment used in water are to be agreed with G.L. in each single case.
> G.L. also says insulation must be resistant to saltwater & oil vapors, not be hydroscopic & has to
> be flame retardant & self extinguishing.
> PTFE has a very high flash point so possibly gains approval for internal use from that perspective.
>    There is a standard for electrical cable for boats "UL1426", & when you search for marine electrical
> wire it will quote a standard like that.
> For sizing wire for submersibles ABS refers you to part 4, chapter 8 of the "steel vessel Rules" &
> table 6 in section 3.
>    It started to get complicated as G.L. have a section Annex E that deals with umbilicals etc.
> I came to the conclusion that I would use a PVC insulated marine grade wire that conformed to the
> UL1426 standard for external use. And use PTFE insulated wire inside the hull. My thinking on going
> with PVC over PTFE externally is that my glues would be more likely to stick to PVC than Teflon (PTFE)
> on my home baked through hulls.
> Cheers Alan
> 
> 
> 
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