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MasterTheNEC

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Do you have a link to this report, cant find it. I remember they did something similar with SER a while back taking it to the 60*C column over thermal insulation concerns.


Now, my understanding behind 310.16 changing to 310.15 was for the unification between NEC and CEC wire tables? Perhaps I became confused and misstated the dwelling table service feeder chart. My bad. I meant the regular 60, 75 and 90*C tables that changed some of the currents around.
I do have the actual study...I will see if I can dredge it up and post it.

The chance from Section 310.16 to 310.15 as to meet the style manual. When you reference a table it has to be within the section referenced so while Section 310.15 was talking about various adjustments and corrections..it should not have referenced Section 310.16 which is why they dropped it back into 310.15 and just changed it to Section 310.15(B)(16)...hey at least they retained the "16" somewhere.

Now in terms of CEC, they did change a few ampacity values to match up with that standard...but nothing in terms of the actual section itself as that was all based on meeting the style manual more closely.

Anyway...I will find that report...it was rather good but in terms of Type SE Cable...the test (if any) were not as extensive and are probably bias to the products being tested. The interesting fact is that while Type NM Cable as "in contact with" and Type SE Cable as " installed in"....are two different things in my opinion...when if you never install Type SE Cable "in" thermal insulation...but only in contact with it.....but i will leave that for another day.
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
They probably do in a way...at least 6 of the organizations have representatives on most if not all of the code panels, but those organizations don't always agree with each other.

I see the same names repetitively , so to assume some manner of premeditation among them isn't far fetched

~RJ~
 

mbrooke

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I do have the actual study...I will see if I can dredge it up and post it.

The chance from Section 310.16 to 310.15 as to meet the style manual. When you reference a table it has to be within the section referenced so while Section 310.15 was talking about various adjustments and corrections..it should not have referenced Section 310.16 which is why they dropped it back into 310.15 and just changed it to Section 310.15(B)(16)...hey at least they retained the "16" somewhere.

Now in terms of CEC, they did change a few ampacity values to match up with that standard...but nothing in terms of the actual section itself as that was all based on meeting the style manual more closely.

Anyway...I will find that report...it was rather good but in terms of Type SE Cable...the test (if any) were not as extensive and are probably bias to the products being tested. The interesting fact is that while Type NM Cable as "in contact with" and Type SE Cable as " installed in"....are two different things in my opinion...when if you never install Type SE Cable "in" thermal insulation...but only in contact with it.....but i will leave that for another day.

What do you mean by style manual?
 

MasterTheNEC

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Ok, that makes more sense now. :)

Have you been to any new CMP meetings?
Yep...just recently got back a few months ago from the Public Input meeting in Hilton Head. I will be at the Public Comment stage as well in San Diego and hopefully on Panel 17
 

MasterTheNEC

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Now I am not aware of any study on the thermal effects of a Type SE Cables installed in Thermal Insulation at this time. While the Type SE Cables do have inner conductors rated 75C or 90C, the product rating itself (on the PVC sheathing) is typically at 75C.

One Wire and Cable Manufacturer believes that the reduction to the 60C ampacity values when Type SE Cable (interior use) is installed in thermal insulation, they feel the NEC should be revised to permit the use at 75C as stated on the products markings. However, the majority of Wire and Cable Manufacturers disagree due to a lack of testing under this condition of use.

in the end......we will see what the CMP does in San Diego come November.
 

mbrooke

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Now I am not aware of any study on the thermal effects of a Type SE Cables installed in Thermal Insulation at this time. While the Type SE Cables do have inner conductors rated 75C or 90C, the product rating itself (on the PVC sheathing) is typically at 75C.

One Wire and Cable Manufacturer believes that the reduction to the 60C ampacity values when Type SE Cable (interior use) is installed in thermal insulation, they feel the NEC should be revised to permit the use at 75C as stated on the products markings. However, the majority of Wire and Cable Manufacturers disagree due to a lack of testing under this condition of use.

in the end......we will see what the CMP does in San Diego come November.

I think so to, 75*C should be allowed for SE when not covered in insulation.


Now, I have a question. Is there a possibility that NM is restricted to 60*C due to the paper inside? I ask because Canadian NMD does not contain paper and is allowed to be used at 75*C, ie where #6 NM is used here at 50amps #8 NM is allowed in Canada. I came across this which is though provoking:


http://www.electriciantalk.com/f31/60-75-c-102986/



BTW, thank you for the UL study, its very interesting :thumbsup::)
 

MasterTheNEC

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I think so to, 75*C should be allowed for SE when not covered in insulation.


Now, I have a question. Is there a possibility that NM is restricted to 60*C due to the paper inside? I ask because Canadian NMD does not contain paper and is allowed to be used at 75*C, ie where #6 NM is used here at 50amps #8 NM is allowed in Canada. I came across this which is though provoking:


http://www.electriciantalk.com/f31/60-75-c-102986/



BTW, thank you for the UL study, its very interesting :thumbsup::)

Actually the standard (UL 719) permits us to manufacturer Type NM-B Cable with or without the paper inside. So based on UL 719 I would say the paper plays no role in the determination of the "in contact with" aspect of the ampacity reduction. Actually 6 NM-B is ok for 55 Amps but as with many ampacity changes to Table 310.15(B)(16) over the last few cycles, it has been more of a harmonization thing than anything else. The CEC's lack of direction in terms of "in contact" with thermal insulation probably drives that.

Now I am not saying that possibly the NM products used in Canada are slightly different....just do not believe the paper plays a role in that since again UL 719 permits paper or paperless Type NM-B Cable.
 

mwm1752

Senior Member
Location
Aspen, Colo
Sorry if this has already been asked - to many responses to read -- I have a couple of code changes submitted will the CMP notify me when the first draft is able to have public comment?
 

MasterTheNEC

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Sorry if this has already been asked - to many responses to read -- I have a couple of code changes submitted will the CMP notify me when the first draft is able to have public comment?
Too many responses.....dude their are threads in here with 100's of responses...all saying the same thing...over and over and over...lol......but to answer your question, you have an account with NFPA in which you submitted your PI's. When the door is open for PC's I am sure the NFPA will send out a notice to all NFPA Members as well as a notice on the NFPA website. The CC is meeting in the next few weeks to tidy things up and then the First Draft will be released after that.

The full schedule of release is available on the NFPA website under the NFPA 70 document information.
 

bphgravity

Senior Member
Location
Florida
I will be attending the CC meeting in Fort Lauderdale next month and will report if anything "big" takes place. I also have access to all the FR's and would be happy to look up your PI's to see what happened to them...

And congratulations to the new CMP-17 member... ;)
 

MasterTheNEC

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Location
McKinney, Texas
Occupation
Master Electrician & Director of Codes and Standards
I will be attending the CC meeting in Fort Lauderdale next month and will report if anything "big" takes place. I also have access to all the FR's and would be happy to look up your PI's to see what happened to them...

And congratulations to the new CMP-17 member... ;)
Thanks Fella....Keep up the GREAT WORK !
 

mbrooke

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United States
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Actually the standard (UL 719) permits us to manufacturer Type NM-B Cable with or without the paper inside. So based on UL 719 I would say the paper plays no role in the determination of the "in contact with" aspect of the ampacity reduction. Actually 6 NM-B is ok for 55 Amps but as with many ampacity changes to Table 310.15(B)(16) over the last few cycles, it has been more of a harmonization thing than anything else. The CEC's lack of direction in terms of "in contact" with thermal insulation probably drives that.

Now I am not saying that possibly the NM products used in Canada are slightly different....just do not believe the paper plays a role in that since again UL 719 permits paper or paperless Type NM-B Cable.

In US NM-B, what temperature is the outer jacket designed for?
 

MasterTheNEC

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In US NM-B, what temperature is the outer jacket designed for?
ironically I do not believe at this time their is any temperature requirement on the outer sheathing except to meet the minimum values in UL 1581 and 2556. I will have to look at those standards in order to comment on that since it is not an everyday item for me to review. Generally the product sample is submitted to UL for original evaluation and then in subsequent surprise visits they take samples to ensure continued compliance. I will look at those test standards and let you know. However, I do not see anything in UL 719 that addresses that directly.
 

mbrooke

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ironically I do not believe at this time their is any temperature requirement on the outer sheathing except to meet the minimum values in UL 1581 and 2556. I will have to look at those standards in order to comment on that since it is not an everyday item for me to review. Generally the product sample is submitted to UL for original evaluation and then in subsequent surprise visits they take samples to ensure continued compliance. I will look at those test standards and let you know. However, I do not see anything in UL 719 that addresses that directly.



That would be awesome! :)

I guess I am wondering what is holding NM back to 60*C when it could in theory handle 75*C. Type AC cable can run at 75*C when not in thermal insulation, and my understanding MC is regardless.
 
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