tray cable use ?
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Re: tray cable use ?
Roger, the tray cable was use in a resident, there were a main disconnect outside ,and two subpanels inside of the resident feed by tray cable. My question is ,when using tray cable without putting in it a cable tray, ...just runninig it through the walls as nm cable, without physical protection.
Roger, the tray cable was use in a resident, there were a main disconnect outside ,and two subpanels inside of the resident feed by tray cable. My question is ,when using tray cable without putting in it a cable tray, ...just runninig it through the walls as nm cable, without physical protection.
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- Mission Viejo, CA
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- Professional Electrical Engineer
Re: tray cable use ?
How did this get in Exam Preparation?
In any case, Roger is correct and it?s a shame. Let me rephrase that. It isn?t a shame that Roger is correct, it?s a shame that TC can?t generally be used as an open wiring method. It?s a vastly superior product to NM. It meets or exceeds every UL flame test and, if specified, every IEEE one as well. In fact, most manufactures won?t waste their resources making a product that won?t pass the IEEE tests too. It?s too costly to maintain multiple product lines.
A less known fact is that virtually every TC listed cable will also pass the UL crush/impact test for MC [336.10(6)]. Again, most domestic manufactures won?t waste their time making a product that won?t pass it. As full disclosure, most TC cable easily pass the UL test, MC generally surpasses it. A small ?failure rate? is accepted by the UL crush/impact test. TC will pass the test with an occasional ?acceptable? failure. Most MC cables will have no failures at all.
Having worked on this issue closely over the last 15 years, it is my opinion that the open wiring limitations on TC are strictly protectionist. The folks that make money keeping the status quo have sufficient numbers on CMP 7 to veto any change. It only takes a third of a CMP to veto a change.
The case under discussion is definitely a good occasion for an AHJ to exercise 90.4 and ??permit [an] alternative method[...] where it is assured that equivalent objectives can be achieved by establishing and maintaining effective safety.?
[ July 04, 2004, 09:44 PM: Message edited by: rbalex ]
How did this get in Exam Preparation?
In any case, Roger is correct and it?s a shame. Let me rephrase that. It isn?t a shame that Roger is correct, it?s a shame that TC can?t generally be used as an open wiring method. It?s a vastly superior product to NM. It meets or exceeds every UL flame test and, if specified, every IEEE one as well. In fact, most manufactures won?t waste their resources making a product that won?t pass the IEEE tests too. It?s too costly to maintain multiple product lines.
A less known fact is that virtually every TC listed cable will also pass the UL crush/impact test for MC [336.10(6)]. Again, most domestic manufactures won?t waste their time making a product that won?t pass it. As full disclosure, most TC cable easily pass the UL test, MC generally surpasses it. A small ?failure rate? is accepted by the UL crush/impact test. TC will pass the test with an occasional ?acceptable? failure. Most MC cables will have no failures at all.
Having worked on this issue closely over the last 15 years, it is my opinion that the open wiring limitations on TC are strictly protectionist. The folks that make money keeping the status quo have sufficient numbers on CMP 7 to veto any change. It only takes a third of a CMP to veto a change.
The case under discussion is definitely a good occasion for an AHJ to exercise 90.4 and ??permit [an] alternative method[...] where it is assured that equivalent objectives can be achieved by establishing and maintaining effective safety.?
[ July 04, 2004, 09:44 PM: Message edited by: rbalex ]
Re: tray cable use ?
Bob, I whole heartedly agree. Given the applications permitted, and a pretty extensive use of TC in my career, (a lot of industrial) I would also prefer and even recommend it for this if it were allowed (
BTW it's Roger.
Roger
Bob, I whole heartedly agree. Given the applications permitted, and a pretty extensive use of TC in my career, (a lot of industrial) I would also prefer and even recommend it for this if it were allowed (
BTW it's Roger.
Roger
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
Re: tray cable use ?
Roger - my deepest apologies :roll:
Roger - my deepest apologies
:roll: - Status