Cable Tie for outdoor Run in Offshore conditions

[Franck YOUDJEU]

Dear members,
I would request your lights and knowledge regarding the use of PVC coated Stainless Steel cables-tie for Offshore project since I'm working as Electrical Engineer for EPC Contractor.
Our specification is requiring the use of PVC Coated over Stainless Steel Cable tie for Outdoor cables, however, our Subcontractor didn't follow this requirement and the Cable tie is in Stainless Steel only.
I have initially suspected the purpose of having the coating has been defined to avoid rust but since the tie is in stainless steel there is no real risk of corrosion. My second hypothesis has been to make the surface of contact between the cable and tie smooth in order to avoid any scratches or abrasion on the cable outer sheath. I've checked internally with my Company Senior Engineer to understand the considerations which have been driven this requirement since I notice IEC Standard 61892-6, do not mention any coating for Cable Tie in Offshore, however nobody seems having question this features before, only saying that it's our Company Standards.
The cable will be installed for 25 years, I wonder if the absence of coating over the Stainless steel tie could lead to premature malfunction.
Yours feedbacks and advice will be really helpful for my knowledge.

 

[Franck YOUDJEU]

Photos of tie in question

 

[waross]

Does this help?

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[FreddyNurk]

A few thoughts:
If its offshore I'd expect that stainless steel by itself may not be enough to prevent corrosion by itself. On the other hand, PVC coating exposed to sunlight and so on may not last the expected duration either, and may not comply with any Low Smoke Zero Halogen requirements that may also exist.

Other aspects that may be prevalent in terms of usage of cable ties are whether the ties are used to secure any power cables, as opposed to control & communications cabling, and whether such cable ties as shown in the photos are adequate to brace power cables with the prospective fault levels experienced.

There is also the consideration of whether its actually a contract issue and the subcontractor gets told to replace it as its non-compliant, and whether the requirement was adequately disclosed to the subcontractor prior to engagement.

EDMS Australia

 

[TugboatEng]

Stainless steel is barely adequate for offshore installations that are exposed to salt spray but regulations require metallic strapping. The regulations also require that the strap does not chaffe the cable. Rubber liners are often used but I find them to be poor performers as they are sensitive to environmental exposure. Plastic coatings do work well to satisfy the regulatory requirement while also being durable. Bronze banding would be ideal but sadly does not exist.

You should also look in to rules about the width of the strapping. Your pictures look like you should be using 1/2 inch strapping. I'll have to dig around to see if that's a rule. We use 46CFR and IEEE-45 in the USA for offshore wiring practices.

 

[FacEngrPE]

Using undersized strapping seems to be normal. The other situation I have encountered is not realizing that there is a limit to the number of cables that can be banded together.