ECN Forum

Plastics-Sun Damage

Posted By: Trumpy

Plastics-Sun Damage - 06/07/05 08:53 PM

{Photos and information submitted by Alan Belson}

Pic 1. The catenary running to my shop is a 3/16" stainless steel stranded wire, with 2 cables I supported on plastic tie-wraps. The nylon has rotted in the sun and some of the ties have snapped after only 3 years. Cables look fine, they're black pvc sheaths.
Any ideas on a better way to support the cables- the span is about 30 ft. This is a temperate climate, probably not much different to New England, certainly not sub-tropical.

[Linked Image]

Pics 2,3. More sun damage. Looking at my cables, up a ladder, I noticed that the PoCo's flexible pvc conduit is also cracking up with sun damage . It was black plastic, rewired in 1998. I'll contact them.

[Linked Image]

[Linked Image]

Alan.
Posted By: Trumpy

Re: Plastics-Sun Damage - 06/07/05 09:17 PM

Interesting photos Alan.
Some plastics are made for exposure to sunlight and some aren't.
That flexible conduit looks exactly like the type of conduit here called Cobra-flex.
It melts away before your very eyes in sunlight.
Catenaries are the easiest way to support cables for over-head spans, especially where the cable(s) would not support thier own wieght.
Looks like the PoCo should have used better quality cable ties and going by the second pic, the PVC cement had run out as well.
I use Ty-Rap branded ties and I've never had a problem with them so far as long as you use the black ones and not the white (indoor) type. [Linked Image]
Posted By: chipmunk

Re: Plastics-Sun Damage - 06/08/05 01:07 AM

I second what Trumpy said about the black UV stabilized cable ties. Another thought may be to wrap a couple of turns of self amalgamating rubber tape (of the type used for satellite connections outdoors) round the catenary at the points where there are ties. It's a little time consuming but it does prevent the ties from wearing through where they are in contact with the catenary, and it seems to hold up pretty well to weathering. I have known even slight movement to severely weaken the ties by sheer wear, if they have been exposed to high winds, even intermittently. I am wondering whether there is much ozone in the air there, as that can accelerate aging greatly.
Posted By: sierra electrician

Re: Plastics-Sun Damage - 06/08/05 03:31 AM

Pic #1: Use TriPlex its rated for the application. If it is Data Cable it also sold in multiconductor with a "Messenger" attached.
Pic #2: PoCo Conduit is actually ENT (Smurf Tube for the blue color) not rated for exterior or exposed use. In wall or above the grid only.

Rob
Posted By: pauluk

Re: Plastics-Sun Damage - 06/08/05 08:07 PM

Alan is located in France. I don't think they use triplex there -- We certainly don't have it in England.

Is it just me, or do a couple of bends on that PoCo conduit seem a little tight? Did EDF install this on a Friday afternoon, or maybe just before the obligatory French 2-hour lunch break?
Posted By: Alan Belson

Re: Plastics-Sun Damage - 06/09/05 10:48 PM

French workers start early in the day, after a large bowl of coffee drunk with a spoon and into which they dunk their bread. Then they have their main meal at lunchtime- practically always the full works; aperatif, red wine, entree, bread, plat, cheese, dessert, coffee, and this does take a full hour and a half plus, what with all the kissing, hand-shaking and talking. Generous portions too, all prepped from fresh ingredients, for around US $10 at a cafe or bar, (look for trucks parked up, an indication of a good chef!). Then they work late, so are still putting in a full 8 hour + workday. The 35 hour week law means most ouvriers get Friday afternoon off for 'le week-end'. Evening meal is just a snack.
And many times you'll find Denise and I getting our heads in the midday cafe-trough with them, although some of the cheeses are, shall we say, an aquired taste! (Livarot!!)
Anyway, I'm off the tell EDF about their rotted plastic tomorrow, armed with my photos. I can tell you I have no high hopes of any action, all I expect is a gallic shrug and 'un ingeneur' will call eventually, (peut etre).
Can't fall over, nothing to stop it!

Alan

PS. Thanks all for the stuff on black uv tie-wraps, they arrive 21st June with my grandchildren from Blighty.
Posted By: Alan Belson

Re: Plastics-Sun Damage - 09/01/05 10:19 PM

The tie-wraps arrived, but I never got round to fitting them, other more interesting things, as usual, got priority. Last night, ye come-uppance; the old catenary ties all finally snapped off 'domino-style', and the cables fell into the yard. They landed smack on top of my Opel (GM) and some friends over from England's Land-Rover. Ooops! Luckily, no damage to the cables. [Linked Image]
Alan
Posted By: Trumpy

Re: Plastics-Sun Damage - 09/02/05 05:53 AM

Alan,
Somewhere at work there is a picture of a car with a hole in the bonnet after a rusty insulator pin snapped and was pulled down by the weight of the cable it was holding.
My guess was that the actual porcelain insulator that went through the metal.
There is a fair bit of wieght in a overhead wire of any size.
Quote
they arrive 21st June with my grandchildren from Blighty.
From where?, is this a new country? Or have they re-named England?.
Posted By: Alan Belson

Re: Plastics-Sun Damage - 09/03/05 09:02 AM

Mike,
"Blighty" is, or was, slang for England.
It's a corruption of the Hindu word bilayati, meaning 'foreign', and was inevitably corrupted to 'blighty' by Indian Army soldiers, around the 1860s. Popularised in 1915 by jingoistic war-songs like "Take me back to dear old Blighty, Put me on the train for London Town" etc. In Oz/NZ the term would be Old Dart, Old Country perhaps?
Adaptable language English, isn't it!
Alan
© 2021 ECN Electrical Forums