MoS Issues

[George Stolz]

How do you go about changing the manual of style?

My motives are as follows. I thought this was enough of a divergence that it warranted it's own topic. In the (now becoming infamous) undercabinet thread, Mike posted the following:

Originally posted by jwelectric:
In 400.8 (1) we are told that a flexible cord can not be used as a substitute for fixed wiring. Then it would seem that in order to install this permanently installed audio appliance we are required to use a plug and receptacle except 640.21 allows us the relief to bypass this plug that would other wise be required to be installed in series with the equipment. The phrase ?direct connection? mentioned in 640.21 clearly states that we are not required to install a disconnect (plug) in series with this hard wired flexible cord to a permanently installed appliance. This has the same meaning as the series over current device mentioned in 695.4 (B) (1).

While my initial reaction was disbelief, upon closer review, I discovered his basic interpretation was valid.

For the record, I flatly disbelieve that 640.21(E) was intended to permit a cord to be permanently connected to premises wiring. But, the way it is worded, in combination with the beginning of the Article, it can be read that way.

640.9 Wiring Methods.
(A) Wiring to and Between Audio Equipment.
(1) Power Wiring. Wiring and equipment from source of power to and between devices connected to the premises wiring systems shall comply with the requirements of Chapters 1 through 4, except as modified by this article.

620.21(E) Between Equipment Racks and Premises Wiring System. Flexible cords and cables shall be permitted for the electrical connection of permanently installed equipment racks to the premises wiring system to facilitate access to equipment or for the purpose of isolating the technical power system of the rack from the premises ground. Connection shall be made either using approved plugs and receptacles or by direct connection within an approved enclosure. Flexible cords and cables shall not be subjected to physical manipulation or abuse while the rack is in use.

Essentially, what I am getting at is that there needs to be a sweeping change in the way the NEC deals with superceding rules. Perhaps I just need a better understanding, and in the course of time someone is going to clarify the "chain of command" in this matter. As it stands, as a user of the NEC (pretty good at it sometimes), this chain is unclear.

In NEC-2002, Article 527 (NEC-2005 Article 590) sets the tone for this concept, because that's what the entire article is about. Unfortunately, this tone isn't that hot either.

527.4 General.
(A) Services. Services shall be installed in conformance with Article 230.
(B) Feeders. Feeders shall be protected as provided in Article 240. They shall originate in an approved distribution center. Conductors shall be permitted within cable assemblies or within multiconductor cords or cables of a type identified in Table 400.4 for hard usage or extra-hard usage. For the purpose of this section, Type NM and Type NMC cables shall be permitted to be used in any dwelling, building, or structure without any height limitation. permitted.

527.2(A) makes a sweeping statement about the whole article, and then it's assumed that 527.4(B) is saying, 240 applies except for this and this and this.

In general, the NEC does not seem to give due credit to how profound these huge exceptions can be, and how profoundly different the same section can be interpreted. So, some sort of master key seems to be the answer, in my mind. Something that says, This section supercedes what you know about that other section. Something brief, but clear that when you see that key, you know the order of things.

Sorry for (my typical) long post, but I am very interested to hear other's opinions on this.

[ May 07, 2005, 08:14 AM: Message edited by: georgestolz ]

 

[iwire]

Re: MoS Issues

George I am not clear what you are asking.

IMO 620.21(E) simply states that the flexible cord may be directly connected to the premise wiring system.

Thats it no more.

It does not relive the requirements for a disconnecting means within site of the amplifiers.

That disconnecting means may be ahead or after this flexible cord connection to the premises wiring.

There are a few exceptions (of course

 

[George Stolz]

Re: MoS Issues

I could very well be wrong, but it seems like the NEC would normally abhor a permanently connected cord, and a sound system doesn't seem like a very compelling reason to discard that general rule.

(A) Between Equipment and Branch-Circuit Power. Power supply cords for audio equipment shall be suitable for the use and shall be permitted to be used where the interchange, maintenance, or repair of such equipment is facilitated through the use of a power supply cord.

(A) & (E) seemto contradict each other. How does hardwiring a cord to premises wiring "facilitating the interchange, maintenance, or repair of such equipment"? It's more difficult if it's hard-wired. Permanent methods exist. Why would this be?

I guess it does say what it meant to say, given the name of 620.21.

I'll compile my thoughts and return. For now, I think I'm an idiot and spoke too soon.

 

[jwelectric]

Re: MoS Issues

George I do believe that you are being to conceive the true meaning of the code and how it works. Much times the definition of a word or term is found by reversing the train of though.

As outlined in 400 this installation is illegal with out a cord plug. I contend that the phrase ?directly connected? as quoted here is to relieve the use of the cord cap that would other wise be required.

Although some here would believe that I just made all this up, and let me thank them for affording me with this much intelligence, I did do some research. Of course any one who knows me would have known this in the first place.

In 1996 the mention of flexible cords can be found in 640-7 where it states that, ?provided such conductors are not in direct electrical connection and are equipped with a current-limiting means.?

In the 1993 cycle we find the requirement for circuit overcurrent protection in 640-10 (page 670) which states, ?Overcurrent devices shall be located as near as practicable to the source of power supply?

See I did research my findings.

 

[iwire]

Re: MoS Issues

Originally posted by jwelectric:
As outlined in 400 this installation is illegal with out a cord plug. I contend that the phrase ?directly connected? as quoted here is to relieve the use of the cord cap that would other wise be required.

I agree with your contention, this section lets us forget about the general rules in article 400 and directly connect the cord to the premise system.

However this does not relive the need for a means to disconnect the ungrounded conductors from the utilization equipment.

What I truly do not understand is how you can make a distinction between direct and plugged then in the same post call it the same thing?

It is illogical.

This is not a personal attack just a statement of the facts as I see them.

 

[jwelectric]

Re: MoS Issues

It is because you don?t read the post and is probably the same way you read the code. The phrase direct connect as outlined in the article you have posted is to show the relief of the disconnection means and over current protection.

In the definition of lighting outlet the phrase directly connected means to plug this fixture into the receptacle of the small appliance circuit. The light goes directly to the small appliance circuit.

But if I installed an overcurrent device between the receptacle and the light then I wouldn?t have small appliance circuits I would have small appliance feeders. For a man who I looked up to on Dave?s site why are you so blind to this?

 

[iwire]

Re: MoS Issues

Originally posted by jwelectric:
It is because you don?t read the post and is probably the same way you read the code. The phrase direct connect as outlined in the article you have posted is to show the relief of the disconnection means and over current protection.

Are you now saying 640.21(E) relives the need for a means to disconnect the ungrounded conductors from the source of supply?

And that same section relieves the need for overcurrent protection on that circuit.

I do not see that section saying that at all.

Please show me where it says that?

640.21 Use of Flexible Cords and Cables.

(E) Between Equipment Racks and Premises Wiring System. Flexible cords and cables shall be permitted for the electrical connection of permanently installed equipment racks to the premises wiring system to facilitate access to equipment or for the purpose of isolating the technical power system of the rack from the premises ground. Connection shall be made either using approved plugs and receptacles or by direct connection within an approved enclosure. Flexible cords and cables shall not be subjected to physical manipulation or abuse while the rack is in use.

All that section changes is the requirements of article 400, it does not change the requirements of 240 or any other article.

Bob

 

[jwelectric]

Re: MoS Issues

There you go twist it around a little.
I do believe we were talking about the flexible cord not the branch circuit feeding the cord.
Have you ever saw a code book before today, this is to say like 1990, ?93, ?96, ?99 or 2002? Do you think they would have any bearing as to how today?s code is written?

ps two people two threads and you still can't get me down. Damn I'm good!!!!!!!!!!!

 

[iwire]

Re: MoS Issues

Mike (it is Mike right) I have those code books within reach right now.

They are junk now, they mean nothing, all that matters is what is written in todays NEC.

This is not to say that following the origin of a code is not helpful or enlightening.

I still fail to see where this section references overcurrent protection or the required disconnecting means for servicing.

However that is not at all why I brought that section up.

I brought that section up only to show how how the NEC separates a hardwired connection from a direct connection

I have not tried to, or believe I have twisted anything around.

Bob

 

[jwelectric]

Re: MoS Issues

Bob
Yes it is Mike. I am going to try to talk to you as though I was talking to a class room. I am not intending to be looking down on you or as I think that I am so smart, but only as though I am teaching my self a lesson in history.

In the ?93 code on page 670 section 640-7 is the requirements for flexible cords and their installation. We are told that conductors are not to be in direct electrical connection with the power-supply conductors and are to be equipped with a current-limiting means
In 640-10 Overcurrent protection shall be provided as follows: (a) Heater or Filament (cathode) (b) Plate (Anode-Positive) (c) Control Grid and (d) location the overcurrent devices shall be located as near as practicable to the source of power supply.

In the ?96 cycle on pages 731 and 732 we find the same wording as outlined above. When we move to the 1999 cycle we find that the whole article has been changed. In the ?93 and ?96 cycles article 640 only had 13 sections but now in the 1999 cycle the last section is 640.46 found on page 463.
Not only has this article gotten bigger but audio equipment no longer has vacuum tubes so the requirements for the installations can be relaxed a little. We no longer have to use a space cloud enveloped in a glass tube to amplify the signals we are transmitting.

Now the code panel is faced with the changing of the type of amplifiers that are being produced and installed. With the newer PNP and NPN transistors we are allowed to connect our supply conductors to our equipment with out the worry of blowing a tube and letting all them space cloud electrons escape.

How can the code panel tell us that we no longer have to comply to, ?conductors are not to be in direct electrical connection with the power-supply conductors and are to be equipped with a current-limiting means??
How about they say that we can take the current limiter out and go straight to the equipment or directly to the equipment or maybe they could say directly connect with out overcurrent in series with.

This is what took place on page 461 0f the 1999 cycle of the NEC. Note the line on the page. This is to show that this is new to this cycle.
Now I am not going to search the archives for the ROP or POC on this, I will leave this to you.

This is the best explanation I have to explain direct connect as outlined in 640.21. we can do a search on the CD of the 2005 and find that in 250.188 (E) there is no way that we can run a buried pipe or fence and directly connect it to a piece of Mobile Equipment.

This is all the time I will ever spend on this weather you accept or reject this explanation is entirely up to you.

 

[iwire]

Re: MoS Issues

Well I do reject it as todays 640.21(E) has nothing to do with 1993s 640.7.

The only thing they have in common is flexible cords and they both are located in article 640.

As you said yourself the entire article has changed.

Bob

 

[rbalex]

Re: MoS Issues

To answer Georges question. There are actually two Manuals of Style. One General NFPA MoS and a separate one for the NEC. In theory, the NEC MoS is self-subordinate to the NFPA MoS, meaning unless it specifically mentions a separate methodology (like Section Numbering) it falls back to the NFPA.

Suggestions to change either one is very similar to making a Proposal; in fact, I'd use the same format and submit the suggestion to the Secretary of the Standards Council. The General MoS is handled by the Standards Council directly; the NEC MoS is handled by the SC with input from the NEC Tech Coordinating Committee.

You need to know this too: updating either MoS DOES NOT mandate updating ANY Standard. It just regulates how future Proposals are to be reviewed; however, MANY Proposals are often made just to bring older style text into conformance.

 

[George Stolz]

Re: MoS Issues

Mike, Bob, Bob, thanks for the replies.

I will let this soak in, and see where it takes me.

 

[George Stolz]

Re: MoS Issues

Originally posted by georgestolz:
For now, I think I'm an idiot and spoke too soon.

That's 100% correct. When I look at 90.3, I see a much more elegant solution to my pickle than the mess I was contemplating. :roll: