Sisal Rope

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Mike01

Mike01

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Something I came arcoss while looking at a 480V substation installation guide it indicates for short circuit strength the line and load conductors shall be wrapped / tied with ?Sisal Rope? as indicated on the following pages. My question has anyone actually done this? Is it a common practice it was in the manufacturers literature??
 
there was a thread sometime back that showed what you are speaking of...tranny feed for a trailer park or something..........maybe someone will post the link or p[icture to that........sorry, gotta run.
 
Lacing

Lacing

Before the days of panduit and nylon ties, it was common practice to lace wiring, especially control and panels. Tying a rope around wires would prevent them from moving during short circuits. The wires will want to move apart when short circuit currents flow. Tying the wires tightly together will prevent that motion. However, sisal rope is probably not approved in the NEC and is not rated 90C.
 
beanland said:
However, sisal rope is probably not approved in the NEC and is not rated 90C.
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Are ty-wraps, tie wire, or other methods "approved" by the NEC ...or the AHJ?
Why would ANY of them need a 90? rating?
 
for the people on here who dont know what sisal rope is, its made of the old fashioned baling twine made from plant fiber, it resembles hemp. (modern baling twine is polypropylene)
 
It was used to lace conductors when terminating. Fairly time consuming but when done properly it was a neat installation.
 
Here's how you rope a CT. It's to keep things from kicking around and pulling out on a hard fault.


23040.jpg
 
There's no special reason why it must be "sisal" rope. Sisal is junk rope. I think the spec for sisal rope is more or less saying that you can use that crap if you want to, but feel free to exceed the min and use cotton rope or broken pieces of old pull rope.
 
mdshunk said:
There's no special reason why it must be "sisal" rope. Sisal is junk rope. I think the spec for sisal rope is more or less saying that you can use that crap if you want to, but feel free to exceed the min and use cotton rope or broken pieces of old pull rope.
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Isn't it always "minimum" ? :grin:

I agree with marc's comments 100%.
 
to answer the tywrap question, a pair of conductors pushing away from eachother during a fault will snap the tywraps. I cant find it but some time ago someone had a link to a video showing a pair of conductors in a cable tray snapping all the tiewraps holding them down during a fault.
 
My Master (way back when) nailed me once for using poly rope for tie downs. He said it has to be Sisal, Manila or Cotton because of the possibility of a flash-over in an electrical compartment. Synthetics will melt and out-gas, possibly accelerating a fire that would have otherwise died quickly with natural fibers.

I have to say though, I have no other proof of that. He was an ex-Marine and Seabee Engineer from the Viet Nam era, so it's likely he just learned it that way and came up with his own justification. Sounds somewhat plausible though. I did find this though from a rope manufacturer: (emphasis is mine)
Nylon
Nylon is the strongest of all ropes in common use. When stretched it has a "memory" for returning to its original length. For this reason it is best for absorbing shock loads, as is the case when lifting or towing. Nylon lasts 4-5 times longer than natural fibers because it has good abrasion resistance and is not damaged by oil or most chemicals. Like manila, nylon has good resistance to ultraviolet deterioration from sunlight, referred to as "U.V. stability".

Polyester
Polyester is very close to nylon in strength when a steady force is applied. However, unlike nylon, polyester stretches very little and therefore cannot absorb shock loads as well...

Polypropylene (Poly)
Because of its light weight, polypropylene is the only rope which floats. For this reason, it is very popular for pool markers and water sports. Poly is affected by sunlight deterioration, more so than any other synthetic or natural fiber rope, but its life can be extended by storing it away from direct sunlight. Poly begins to weaken and melt at 150?F, the lowest melting point of all synthetic ropes. It is not as strong as nylon or polyester, but 2-3 times stronger than manila. ...

Manila
A hard natural fiber, manila is especially resistant to sunlight. It is very popular for public utility construction and repair because it will not melt on contact with hot wires or equipment like synthetics do. It will burn, however, if the temperature is very high or if the rope is in contact with the wires/equipment for an extended period of time. Manila holds knots firmly and stretches very little. ...

Sisal
Sisal, like manila, is a hard natural fiber, but its strength is about 20% less than manila. It too has excellent resistance to sunlight, little stretch, and good knot-holding ability. ... Common uses include gardening, bundling, shipping, and tiedowns where strength is not a critical requirement.
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No mention of cotton, but from that, I'd say that Manila is best, Sisal is the poor man's Manila.

Trivia: Sisal rope is made from Aloe cactus plant fibers or Henequen from Agave leaves (think Tequila), Manila rope is made from Plantain leaves (think Bananas), Hemp is made from Canabis (but we all knew that!). Cotton looks kind of boring by comparison.
 
Wow

Wow

mdshunk,
Very nice job, do you remember what size (diameter the rope was) and just curious on the service size? Thanks. I just recently saw this along with a diagram in an installation guide for low voltage draw-out switchgear line and load terminations and was wondering how often this gets done I have never personally seen this.
 
Mike01 said:
mdshunk,
Very nice job, do you remember what size (diameter the rope was) and just curious on the service size? Thanks. I just recently saw this along with a diagram in an installation guide for low voltage draw-out switchgear line and load terminations and was wondering how often this gets done I have never personally seen this.
Click to expand...
Not my pic. I ripped it off another user a few years ago.
 
Mike01 said:
Something I came arcoss while looking at a 480V substation installation guide it indicates for short circuit strength the line and load conductors shall be wrapped / tied with ?Sisal Rope? as indicated on the following pages. My question has anyone actually done this? Is it a common practice it was in the manufacturers literature??
Click to expand...

It's combustible.
 
Jraef said:
My Master (way back when) nailed me once for using poly rope for tie downs. He said it has to be Sisal, Manila or Cotton because of the possibility of a flash-over in an electrical compartment. Synthetics will melt and out-gas, possibly accelerating a fire that would have otherwise died quickly with natural fibers.

I have to say though, I have no other proof of that. He was an ex-Marine and Seabee Engineer from the Viet Nam era, so it's likely he just learned it that way and came up with his own justification. Sounds somewhat plausible though. I did find this though from a rope manufacturer: (emphasis is mine)


No mention of cotton, but from that, I'd say that Manila is best, Sisal is the poor man's Manila.

Trivia: Sisal rope is made from Aloe cactus plant fibers or Henequen from Agave leaves (think Tequila), Manila rope is made from Plantain leaves (think Bananas), Hemp is made from Canabis (but we all knew that!). Cotton looks kind of boring by comparison.
Click to expand...

Sounds good until you think about it.

Flashover occurs via a conductive path of some sort. Conductive paths are formed by dust AND water.

Which of those ropes are hygroscopic and which are not?
 
weressl said:
Oh, and wait until it gets wet...that will be some fireworks.
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I wired a transferswitch last year that requried the use of lacing cord to prevent the conductors from jumping around. Not really that uncommon of a thing to see inside of switchboards, Even today.
 
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