Sisal Rope

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Laszlo,

To be fair, I don't think that you said that you've actually seen failures caused by roping, prior to post 58.

It is clear that many manufacturers either suggest or 'require' roping.

It may be that manufacturers need to update their suggested practices, based upon field experience.

-Jon
 
winnie said:
Laszlo,

To be fair, I don't think that you said that you've actually seen failures caused by roping, prior to post 58.
Click to expand...

Why would I question the practice if not due to failures? Isn't that obvious?

09-23-2008, 05:57 PM http://forums.mikeholt.com/showthread.php?p=921146#poststop
09-23-2008, 05:58 PM http://forums.mikeholt.com/showthread.php?p=921147#poststop
09-23-2008, 06:17 PM http://forums.mikeholt.com/showthread.php?p=921167#poststop
09-23-2008, 06:21 PM http://forums.mikeholt.com/showthread.php?p=921178#poststop
Yesterday, 12:59 PM http://forums.mikeholt.com/showthread.php?p=921651#poststop
Yesterday, 01:23 PM http://forums.mikeholt.com/showthread.php?p=921662#poststop
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Today, 09:01 AM http://forums.mikeholt.com/showthread.php?p=922093#poststop

winnie said:
It is clear that many manufacturers either suggest or 'require' roping.
Click to expand...

So far we have seen TWO instructions from the same manufacturer, so you can't calim plural.

winnie said:
It may be that manufacturers need to update their suggested practices, based upon field experience.

-Jon
Click to expand...

My points of contention are:
  • If it is such a critical issue - which it is - it should be tested and be part of the UL approval.
  • The bracing should be a manufactured item, not field fabricated and relying on the installers skill - which is fastly dim inishing.
  • The current practice and its implementation produce a failure point in some environment where dust and water accumulation occur as a normal course of aging. The combination of dust and water establishes a flash-over path that is against the NEMA guidelines for panel construction and demonstrably were the CAUSAL source of short circuits and resulted in fires.
  • The bracing material should be subject to the same fire resistance requirements as other electrical support and'or insulating materials are.
  • There are already existing material available that is designed for the specific purpose. The installation should utilize that rather than a field fabricated construct of untested performance.(No-one has produced so far any documentation that has shown that this installation method is/was tested.)
Side point but relevant for the future:
  • The harmonization of NFPA/UL/NEMA should be executed as an integrated effort to address such issues. Since there is no money in it everybody is concentrating on how to gain IEC acceptance and trying to intergate their product into THAT system, seriously neglecting the ANSI market and will lead to the eventual cave in of the ANSI to the IEC system. (Westinghouse gone, GE is selling their lines off left and right, Square D became a french 'maiden', ITE gone, Allis-Chalmers is Siemens, Furnas is Siemens, do I need to go on?)
  • Don't shoot the messenger.
 
Deep breaths, people, we'll get through this. :D

weressl said:
My points of contention are:
  • If it is such a critical issue - which it is - it should be tested and be part of the UL approval.
Click to expand...
It's in the instructions Bob posted before - 110.3(B).

  • The bracing should be a manufactured item, not field fabricated and relying on the installers skill - which is fastly dim inishing.
Click to expand...
I can forget to torque a lug as well, is this any different than following the directions for roping the conductors? Torquing a lug and not allowing the conductor insulation to be damaged by edges in the enclosure are also reliant on the installer's skill, are they not?
  • The current practice and its implementation produce a failure point in some environment where dust and water accumulation occur as a normal course of aging. The combination of dust and water establishes a flash-over path that is against the NEMA guidelines for panel construction and demonstrably were the CAUSAL source of short circuits and resulted in fires.
Click to expand...
Please substantiate this with something other than your word: show us the NEMA guideline for panel construction, and where this is stated. Where/how/when did they demonstrate that roping caused a short circuit and a fire?

  • The bracing material should be subject to the same fire resistance requirements as other electrical support and'or insulating materials are.
Click to expand...
Again, please substantiate.

  • There are already existing material available that is designed for the specific purpose. The installation should utilize that rather than a field fabricated construct of untested performance.(No-one has produced so far any documentation that has shown that this installation method is/was tested.)
Click to expand...
What material are you referring to?

Why must the method be tested (listed) if it is included in the directions?
  • Don't shoot the messenger.
Click to expand...

If you were less brazen about throwing your opinion at people as though it were indisputable fact, then people would take far less glee in exposing holes in your reasoning. If you substantiate your opinion with something tangible, folks won't have as much ammunition to refute your opinion.

You can find that in Civil Discourse 101. ;)
 
My mole buried deep inside GE explained that cable roping is required by UL to be part of the instructions. We went on to discuss that the utility does not do it and and appear to suffer no ill effects.

It is just coincidence I was talking to him about this at an IAEI meeting about two months ago.

it is probably in 891 somewhere.
 
George Stolz said:
Deep breaths, people, we'll get through this. :D
[/list]It's in the instructions Bob posted before - 110.3(B).
[/list]I can forget to torque a lug as well, is this any different than following the directions for roping the conductors? Torquing a lug and not allowing the conductor insulation to be damaged by edges in the enclosure are also reliant on the installer's skill, are they not?
[/list]Please substantiate this with something other than your word: show us the NEMA guideline for panel construction, and where this is stated. Where/how/when did they demonstrate that roping caused a short circuit and a fire?
[/list]Again, please substantiate.
[/list]What material are you referring to?

Why must the method be tested (listed) if it is included in the directions?
Click to expand...

http://dutchclamp.com/products.php

Why anything should be tested? Why not just let manufacturers decide what's good for you and take their word for it.

I have wittnessed two incidences inwolving failures at the rope bracing installation. If my memory serves right, in one case the rope installation appeared to be slightly deviating from the manufacturters instructions, but that did not seem to be the primary cause. What could be determined through forensic investigation that the arc-over occured along the path of the rope and there was evidence of excessive dirtiness and water. The conclusion was that the rope absorbed water(11% water absorbtion ratio for sisal), water attracted dirt, the combination provided a high resistance conductive path that eventually carbonized, increasing its conductance. The increased conductance allowed an even higher current flow, potentially causing the fiber to part-take in the failure. (As organic material it would carbonize under heat.)

I have no interest in convincing anyone. I share my experience as I believe it can benefit others. Take it or leave it, but don't shoot the messenger.

If you wish, go ahead an look up the NEMA panelbuilding guidelines concerning creepeage distances.

Why should one component be fire resistant and the other is combustible? I dunno, to me it seems common sense like a weak link in a chain.

I am done with this subject, shared more than I wanted, definetly argued more than I wanted because I let myself to be drawn into it.

Consider yourself a winner. Congratulation!

Instruct me about civil discourse but not others calling me names FIRST? Look up the word hypocrisy.......
 
ManufacturerS

ManufacturerS

Just an update I have confirmed with another manufacturer that roping is required at or above a certain s.c. level when I receive the information I will post the documentation this will identify two manufacturers require this type of installation.
 
Mike01 said:
Just an update I have confirmed with another manufacturer that roping is required at or above a certain s.c. level when I receive the information I will post the documentation this will identify two manufacturers require this type of installation.
Click to expand...

Curious to see if it is truely required, or required-and/or/maybe-recommended, like Square D info in post #53...
 
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