Section 336-10(7)/Proposal 7-118 Type TC-ER use

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rbalex

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Section 336-10(7)
Proposal 7-118
Log #4088 NEC-P07, pg 70-399​
Recommend: Accept this Proposal

Substantiation: ?The cable is primarily designed to be installed in cable tray and as permitted in 336.10.? The statement is, of course, true. SO WHAT? In all the times this Proposal or ones similar have been made, the Panel HAS NEVER ONCE established a valid technical or safety (valid or not) issue that would reasonably prohibit the alternate use of TC-ER as proposed.

Forget the name - consider the construction. It isn?t even a unique or novel concept. Type TC-ER is obviously superior to Type NM (in any form) yet is restricted from uses where Type NM would be readily permitted. Please spare the semantics that there are applications where neither would be permitted.

This commenter is aware that, while Type TC-ER ??complies with the crush and impact requirements of Type MC ?,? Type MC does, in fact, generally perform better under those qualification tests. If safety were a genuine concern, the appropriate response would be to raise the ?pass/fail? qualification standard ? not arbitrarily prohibit Type TC from a reasonable alternate application.

There is a reasonable safety concern that TC-ER may at some time in the future be proposed as a substitute for Type MC. That is when to reject it - if the application warrants a unique feature of Type MC.
 

infinity

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Bob,

Do you have more information on this type of cable? I'm sure that some of us have never heard of it.
 

rbalex

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First, Thanks 480sparky for the list of links.

TC-ER is essentially Type TC "...that complies with the crush and impact requirements of Type MC..." Like many NEC Chapter 3, conductor and cable Types where a "new" construction or formulation for an "old standard" is introduced, the new construction becomes the general "standard."

Sorta like "-2" or "MC-HL" for any continuously corrugated Type MC. If you order the "old standard," you will still most likely get the "new." It will perform at least as well, is usually less expensive, and isn't worth stocking both constructions to the supplier.

For example, look at the Okonite "Low Voltage Cable" Section 3 and compare Sheets 15 (TC) and 16 (TC-ER). They are virtually identical in physical attributes (weight, dimensions, etc.) but TC-ER is the "stocked" item. Type TC is actually a special order and usually costs more.

IMO the actual objection [for the proposed application] is product protectionism (for Type MC), not safety.
 
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