300.20 Gone Wild

[roger]

The irony is strong.

:lol:

Roger

 

[Smart $]

The irony is strong.

Hey! You should feel right at home with that remark. :thumbsup:

 

[mivey]

Don you are tossing aside basic commonsense in this thread.

Do you really think the CMP that put that rule in place was so removed from the trade they asked for the impossible?


I find the whole notion just silly.

My thoughts exactly. I think Don is yanking our chains a little bit.

 

[iwire]

Hey! You should feel right at home with that remark. :thumbsup:

Oh I am highly opinionated no doubt of that.

Yet the differance is I can, and have on numerous occasions on this forum clearly admitted I was wrong.

 

[mivey]

The irony is strong.

Ooooh suh-nap!

 

[Smart $]

Oh I am highly opinionated no doubt of that.

Yet the differance is I can, and have on numerous occasions on this forum clearly admitted I was wrong.

Your last remark is insinuating that i have not... and you couldn't be more wrong. You have even witnessed a few over the years, but you choose to ignore or forget them so you can harass me of nothing worse than what you yourself commit.

 

[don_resqcapt19]

My thoughts exactly. I think Don is yanking our chains a little bit.

I have never said that common sense has ever been used in writing code rules.

 

[iwire]

I have never said that common sense has ever been used in writing code rules.

Never the less I don't believe for a moment that the CMP would ask for what you believe the section requires.

It makes no sense and is not possible to do.

 

[romex jockey]

I have never said that common sense has ever been used in writing code rules.

I've been reading you since i was no more than a wee apprentice Don

YOU make sense ....

My hope is there are enough of your sort still around to make it all fly straight

~RJ~

 

[peter d]

Yet the differance is I can, and have on numerous occasions on this forum clearly admitted I was wrong.

I have a hard time believing this. :happyno::huh:

 

[Smart $]

I have a hard time believing this. :happyno::huh:

Maybe I should start. :angel:

It's a new year after all, ya know. Happy New Year to all (you too, Bob)...

 

[iwire]

Oh I am highly opinionated no doubt of that.

Yet the difference is I can, and have on numerous occasions on this forum clearly admitted I was wrong.

I have a hard time believing this.

Maybe I should start. :angel:

It's a new year after all, ya know. Happy New Year to all (you too, Bob)...

Two minutes of searching

http://forums.mikeholt.com/showthread.php?t=168941&p=1642684&highlight=I+was+mistaken#post1642684

http://forums.mikeholt.com/showthread.php?t=166681&p=1619986&highlight=wrong#post1619986

http://forums.mikeholt.com/showthread.php?t=162886&p=1580453#post1580453

http://forums.mikeholt.com/showthread.php?t=136745&p=1310299#post1310299

http://forums.mikeholt.com/showthread.php?t=130206&p=1246959&highlight=wrong#post1246959

http://forums.mikeholt.com/showthread.php?t=129569&p=1239614#post1239614

http://forums.mikeholt.com/showthread.php?t=127059&page=2&p=1214180#post1214180

http://forums.mikeholt.com/showthread.php?t=123694&p=1173886#post1173886

http://forums.mikeholt.com/showthread.php?t=123507&p=1171817#post1171817


So here is the thing, when I say I can admit when I am wrong, it is the truth.

I may be grumpy, I may be pain in the rear but I am not a liar.

 

[Smart $]

Two minutes of searching

http://forums.mikeholt.com/showthread.php?t=168941&p=1642684&highlight=I+was+mistaken#post1642684

http://forums.mikeholt.com/showthread.php?t=166681&p=1619986&highlight=wrong#post1619986

http://forums.mikeholt.com/showthread.php?t=162886&p=1580453#post1580453

http://forums.mikeholt.com/showthread.php?t=136745&p=1310299#post1310299

http://forums.mikeholt.com/showthread.php?t=130206&p=1246959&highlight=wrong#post1246959

http://forums.mikeholt.com/showthread.php?t=129569&p=1239614#post1239614

http://forums.mikeholt.com/showthread.php?t=127059&page=2&p=1214180#post1214180

http://forums.mikeholt.com/showthread.php?t=123694&p=1173886#post1173886

http://forums.mikeholt.com/showthread.php?t=123507&p=1171817#post1171817


So here is the thing, when I say I can admit when I am wrong, it is the truth.

I may be grumpy, I may be pain in the rear but I am not a liar.

Let me play the devil's advocate here...

You are wrong about that...!!!


:roll::roll::roll::roll::roll:
Again, Happy New Year, Bob.

 

[don_resqcapt19]

Never the less I don't believe for a moment that the CMP would ask for what you believe the section requires.

It makes no sense and is not possible to do.

I am not saying that they actually asked for and intended that...I am just saying that the words they used require that.

There have been a number of cases where the CMP has written or accepted language that did not reflect the intent of the rule. My favorite example is 346.11 in the 1987 NEC.

346.11 Bends - Number in One Run. A run of conduit between outlet and outlet, fitting and fitting, or outlet and fitting shall not contain more than the equivalent of four quarter bends (360 degrees, total), including those bends located immediately at the the outlet of fitting.

The code was changed for the 1990 code and the new language for 346.11 in the 1990 code is identical to the language in 344.26 in the 2014 code.

The substantiation for the change as presented in proposal 8-80 in the TCR for the 1990 code said that per the definitions a "coupling" is a "fitting" and that the current rule permits 360 degrees of bend between each coupling. The CMP accepted the change, but it is a perfect example of a code rule that had been in the code for many cycles that did not even come close to reflecting the actual intent of the rule.

So in this case, I am just saying that the actual code language...the enforceable rule...does not reflect the intent of the rule.

 

[al hildenbrand]

As far as the original question, I really don't see any real world issue with inductive heating where all of the conductors are within the same ferrous metal conductors, but I see the first and second sentences of 300.20(A) as standing alone, and the second gives a prescriptive requirement, that the conductors be grouped without exception.

I am not saying that they actually asked for and intended that...I am just saying that the words they used require that. . .

So in this case, I am just saying that the actual code language...the enforceable rule...does not reflect the intent of the rule.

So, you are saying that the rule language requires that a multiconductor cable with twisted conductors must maintain the conductor twist inside the enclosure of ferrous metal?

The very definition you have cited for "grouped" is fighting you in your interpretation. The definition of grouped says the conductors need only be adjacent AND NOT in continuous contact.

 

[mgookin]

Let's agree that the code as written results in unintended interpretation and that it could be worded better. For example:


300.20 Induced Currents in Ferrous Metal Enclosures
or Ferrous Metal Raceways.
(A) Conductors Grouped Together. Where conductors
carrying alternating current are installed in ferrous metal
enclosures or ferrous metal raceways, they shall be ar-
ranged so as to avoid heating the surrounding ferrous metal
by induction. To accomplish this, all phase conductors and,
where used, the grounded conductor and all equipment
grounding conductors shall be grouped together.
Exception No. 1: Equipment grounding conductors for
certain existing installations shall be permitted to be in-
stalled separate from their associated circuit conductors
where run in accordance with the provisions of 250.130(C).
Exception No. 2: A single conductor shall be permitted to
be installed in a ferromagnetic enclosure and used for skin-
effect heating in accordance with the provisions of 426.42
and 427.47.

is how it is written.

If it said:

300.20 Induced Currents in Ferrous Metal Enclosures or Ferrous Metal Raceways.
(A) Conductor Location.
Where conductors carrying alternating current are installed in ferrous metal enclosures or ferrous metal raceways, they shall be located so as to avoid heating the surrounding ferrous metal by induction. To accomplish this, all phase conductors and, where used, the grounded conductor and all equipment grounding conductors shall be located in the same ferrous metal enclosure or ferrous metal raceway.
Exception No. 1: Equipment grounding conductors for certain existing installations shall be permitted to be installed separate from their associated circuit conductors where run in accordance with the provisions of 250.130(C).
Exception No. 2: A single conductor shall be permitted to be installed in a ferromagnetic enclosure and used for skin-effect heating in accordance with the provisions of 426.42 and 427.47.

it would eliminate or reduce the probability of misinterpretation.

 

[al hildenbrand]

Let's agree that the code as written results in unintended interpretation and that it could be worded better.

Yes. I agree.

I just don't agree that the ONLY interpretation, as written, REQUIRES the maintained twist of stripped cable conductors is they were factory twisted. Don seems to be saying there is only one interpretation of the second sentence.

Your suggestion of tweaked language for 300.20 is nice.

 

[infinity]

I think it moved on to the requirement that the conductors be grouped within the enclosure and what "grouped" means.

I agree. Twisted is just one form of grouping.

I agree also. The NEC uses the word grouped but as evident in this thread that one word can be interpreted to mean far reaching ridiculous things. The part that Don posted about the Canadian EC is interesting because in large switchboards and switchgear the opposing ungrouded and neutral sections of bus is often separated by several feet.

According to the interpretation outlined in the OP (which is utterly stupid) the panel in the photo will burst into flames shortly. :slaphead:

 

[Smart $]

I agree also. The NEC uses the word grouped but as evident in this thread that one word can be interpreted to mean far reaching ridiculous things.

Here's what I believe to be the intent, and a simple fix in the process.

300.20 Induced Currents in Ferrous Metal Enclosures
or Ferrous Metal Raceways.
(A) Conductors Grouped Together. Where conductors
carrying alternating current are installed in ferrous metal
enclosures or ferrous metal raceways, they shall be arranged
so as to avoid heating the surrounding ferrous metal
by induction. To accomplish this, all phase conductors and,
where used, the grounded conductor and all equipment
grounding conductors shall be grouped together in
accordance with 300.3(B).

 

[jaggedben]

Here's what I believe to be the intent, and a simple fix in the process.

I'd go a step further with the edit.

300.20 Induced Currents in Ferrous Metal Enclosures
or Ferrous Metal Raceways.
(A) Conductors Grouped Together. Where conductors
carrying alternating current are installed in ferrous metal
enclosures or ferrous metal raceways, they shall be arranged
so as to avoid heating the surrounding ferrous metal
by induction. To accomplish this, all phase conductors and,
where used, the grounded conductor and all equipment
grounding conductors shall comply with 300.3(B).

Get rid of "grouped".

I still want to see it say, in some fashion, that it's okay to run a switch leg that's not accompanied by the neutral. But I think that's for another thread.