i have a dumb question

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I wonder if anyone is submitting a proposal to eliminate the usage of SE cable at 60 degrees. Was there really a problem when it was used at 75 degrees?
 
infinity said:
I wonder if anyone is submitting a proposal to eliminate the usage of SE cable at 60 degrees. Was there really a problem when it was used at 75 degrees?
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Never had a problem in all my years. :D I think they are just trying to keep consistency within the nec.
 
infinity said:
I wonder if anyone is submitting a proposal to eliminate the usage of SE cable at 60 degrees. Was there really a problem when it was used at 75 degrees?
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NC will decide by Jan. 1 2009 whether it will amend that section. Apparently the wire manufacturers tested the cable under very abnormal conditions. They loaded the cable at 100% for 5 hours or more and found the cable started to breakdown. Often with se cable we already have figured another 25% into the size for motors, heat, etc.

I also have never seen a problem with SE however the fire caulking is a relatively new thing.
 
SE used for indoor branch circuits and feeders is exposed to the same issues as NM, being buried in insulation.

Keep in mind SE is still good for 75 C when used outside.
 
I'm glad to see the change to 60 c for interior installations of seu and ser. I have been concerned about installations when 4/0 al ser was installed for sub-panels. Per table 310.16 at 75c 4/0 al is listed at 180 amps. Per section 240.4(B) if conditions are met you can size up to a 200 amp overcurrent device which IMOP is a large jump for a cable that size. Where at 60c it is rated a 150 amps much cooler installation. A little pun.:smile: I've seen party stores with many coolers and continuous lighting loads with feeder cables running thru attics and they do get hot!
 
iwire said:
You have heard correctly 334.80 as Dennis pointed out.

By the way it is not 'derating' it is just 'the rating'
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334.80 Ampacity.
The ampacity of Types NM, NMC, and NMS cable shall be determined in accordance with 310.15. The ampacity shall be in accordance with the 60?C (140?F) conductor temperature rating. The 90?C (194?F) rating shall be permitted to be used for ampacity derating purposes, provided the final derated ampacity does not exceed that for a 60?C (140?F) rated conductor. The ampacity of Types NM, NMC, and NMS cable installed in cable tray shall be determined in accordance with 392.11.
Section 310.15(B)(2)(a) states in part: “or where single conductors or multiconductor cables are stacked or bundled longer than 600 mm (24 in.) without maintaining spacing and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(a).” Failure to comply with the appropriate adjustment ampacity derating called for by this table, where nonmetallic sheathed cables may be stacked or bundled, can lead to overheating of conductors.
 
wireways said:
Hey dennis if you are goin to disagree, give code section
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If you are going to make statements then support it with an article number.

Read art. 110.15(C)(1)-- since you stated te 60 and 75 rule I figured you knew where it was. Basically if the terminals are rated 75C and the wire is rated at least 75C then you may use the 75C column for wires under 100 amps. If the terminals are not marked then we must assume 60C. I have yet to see any new equipment with terminals that were not rated 75C
 
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