ECN Forum Forums General Topics of the Trade General Discussion Area # of conductors in conduit

George, along with Electure, I would like to see some substantiation to your claim.

Steve, congratulations on your PE license.

Roger

Roger ---

Perhaps you could substantiate your position.

Perhaps with a state supreme court decision.

---

Asking for "substantiation" is a bit over the top.

An adopted code is a law; the last I looked, the only folks who get to set aside laws are judges.

Sure, there is often room for judgment in the application of a law, and often that's where additional documentation can be handy.

The NEC has numerous places where a provision mentions "engineering supervision." In places other than where such is specifically allowed, I read the code to say "I don't care if you're Thomas Edison - this is the rule!"

As for being part of the "building code," we have to be careful of our language. While there is usually a general 'building code,' such as the IBC, all of the locally adopted codes, as a group, can be said to comprise the "building code."

Some have chided me in the past for having a poor attitude towards engineers. Any cynicism I may have has been influenced by encounters with engineers who felt they had carte blanche to ignore all convention, and do whatever they wished. This is America, however, where the same laws apply to all ... even those with PE tickets.

It is also why I am so strident in asserting that it is the electrician, not the engineer, who is the expert in code matters. An electrician has years of formal training in electrical matters; even an "electrical engineer" has absolutely none. (Check the curriculum at the engineering school of your choice- don't just take my word for it!) Engineers, even EE's, are valuable applied trades, but electrical work is not their trade.

I will concede that the NEC is conservatively written; you can very often 'get away' with pushing things. It also ... pay attention here ... is not a design manual, an instruction manual, or interested in efficiency.

As for de-rating, I admit that applying the tables does not constitute a complete 'engineering analysis' of every possible situation. The tables, for example, do not make any distinction between a lightly loaded convenience circuit, and a fully loaded dedicated circuit. As I said earlier, the NEC is a conservative document.

The irony is that these code rules, as well as many unwritten trade practices, are even today proving their worth in ways that could never have been anticipated when they were written. We are only beginning to understand power quality, harmonics, and transients. Sometimes, the 'little things' make all the difference!

Using 1998 1&2 Family Dwelling Code as an example:

108.1 Allows engineering. Also allows deviations from the prescriptive code. Subsequent

3901.1 & 3901.2 Includes the current NEC as a prescriptive option.

That is sufficient to prove me correct.

George, why do you feel it is over the top ?

I feel it is a reasonable request.

Sorry, but making statements without substantiation is just making statements.

Pointing out codes that allow engineering supervision is not substantiation to your claims.

The provisions that allow engineering are few and are not open signed checks that allow an engineer to write or overrule the particular code.

The reality is that the inspector or AHJ has the hammer unless there is some documented rule that is part of the adopted code that says a PE seal is the hammer.

Roger

Because in being switchlegs, there will never be one time where both conductors will be carrying the same load correct?

'getting my code book for exact reference'..not because I disagree, but for continuing ed's sake.

To further what I stated above:
In New Jersey:
The 'Building Code' consists of one (1) main document (NJ UCC, 5:23) which is LAW, and written as such.

Within the UCC, and adopted are various 'Codes', one of which is the current 2005 NEC, with minor amendments.

The AHJ is responsible to enforce said Code, be it Electrical, Plumbing, Building, Fire, ADA, Asbestos Remediation, etc.

I am not 'anti-engineer'; I respect those that persue that career, but, rules (laws) are rules.

John

George your claim that "The NEC is not the Code" is not true in Texas, and that point is specifically stated in this NEMA release from a couple of years ago.

Here is substantiation:
_____________________________________________

Code Alert: Texas, 01 June 2005
NEMA > Standards > Field Representative Program > Code Alerts > Code Alert: Texas, 01 June 2005

On Wednesday, June 1, 2005 the Texas Commission of Licensing and Regulation formally adopted the 2005 edition of the National Electrical Code® as the State of Texas’ basic electrical installation code. Enforcement will be effective on July 1, 2005 and this adoption replaces the 2002 edition of the National Electrical Code®, which was the first State of Texas mandated electrical installation code for all classes of occupancies that was first adopted by the Commission in January 2004 and that went into effect on September 1, 2004.

However, even with the 2005 edition of the National Electrical Code® being adopted by the State of Texas as the basic electrical installation code in the state, incorporated cities in the state may amend the edition of the National Electrical Code® adopted by the state. But, for unincorporated areas outside a municipal jurisdiction, the 2005 National Electrical Code® as written will be the electrical installation code. Texas also adopts the International Residential Code (IRC) for all 1&2 Family Dwellings but did not adopt Chapters 33-42 (the electrical provisions chapters) of the IRC and continues to utilize the National Electrical Code® for electrical installations in one and two family dwellings.
____________________________________________

Here's one for Oklahoma
http://www.nema.org/stds/fieldreps/codealerts/20050719ok.cfm


You may want to update your information.

[This message has been edited by electure (edited 02-09-2007).]

I disagree- Electricians and Power Engineers are both required to be experts in code, but the areas of the code both are expert in vary. For example, engineers seldom get involved with the details- we require a component be grounded, but are largely unconcerned with HOW it be grounded, and the details are left to the electrician. I might specify RGS or compression-couplings on EMT in areas where I'm concerned about parasitic EMI in an electronic facility, or put certain requirements on the size of a neutral, though. Or ensure that specific types of transformers are installed that block harmonics and minimize fault current levels. All these things must be installed by code, and current levels calculated so that ampacities and derating can likewise meet code. So, if it's routine, my drawings tell you what to install, tell you what conductors to install in what conduit/cable tray/etc, and generally leave it at that.

If a question ever comes up on ANY issues of code or design, though, it's the engineer who's called in to make the final determination.

It's only if there are special situations where more detail is required- in some situations, I will pore endlessly over specifications and requirements and technical data from all involved and specify, for example, not only what bolt, which which PRECISE bolt be used and will give you a procedure on how to turn it; if you disagree and want to do it differently, it had better be on the proper form and in triplicate, and you'd better wait for my response before doing anything. I work for the federal government, though- this isn't very likely to happen when wiring up a wal-mart or mini-mall.

[This message has been edited by SteveFehr (edited 02-09-2007).]

A very good response, Steve. I don't want to get into an "us vs. them" thing here, but I do note you were quick to counter my assertion.

What I'd really like to know is what the engineers out there think of George's assertion that the engineer can over-rule the code.

I suppose, if you dig hard enough, you can find decent folks in any field. It's the arrogant loose cannons that make it hard to see them.