The NEC vs. Engineers

[George Stolz]

Heard something interesting today, that makes sense to me but at the same time arouses my ire.

If plans are drawn with a 4/0 CU conductor run to a ground rod, what prevails: the prints, or the NEC.

The NEC states that it shall not be required to be larger than #6. But again, the NEC is a minimum standard. But, then again, is it the inspector's job to enforce design enhancements on the plan?

Curious about other's thoughts on this.

 

[GG]

Re: The NEC vs. Engineers

When I bid a job and they show a 4/0 to a ground rod well then I have to figure in the cost of the 4/0 as opposed to a #6. If I go through the entire prints and bring everything down to the code minimums then I may end up getting the job and losing money.

[ July 19, 2005, 11:49 PM: Message edited by: GG ]

 

[celtic]

Re: The NEC vs. Engineers

Originally posted by georgestolz:


If plans are drawn with a 4/0 CU conductor run to a ground rod, what prevails: the prints, or the NEC.

The prints prevail unless a violation of code.

 

[redfish]

Re: The NEC vs. Engineers

When working for the Government, bigger is better as far as they are concerned. For example if 4/0 is in the spec book and 3/0 is on the plans, then the specs prevail. If 3/0 is in the spec book and 4/0 is on the plans, the plans prevail.

 

[benaround]

Re: The NEC vs. Engineers

George,

The Inspectors in this area all go off the "Approved set of Prints" ,you can't really blame them in this law suit crazy world.

frank

 

[infinity]

Re: The NEC vs. Engineers

Why would the prints determine what the AHJ inspects and not the NEC? If the plans call for one thing and the EC installs another the AHJ is only responsible for the job being code compliant, not to make sure that the customer is getting what he's paying for. That is the customers' responsibility not the AHJ's.

 

[iwire]

Re: The NEC vs. Engineers

Originally posted by infinity:
Why would the prints determine what the AHJ inspects and not the NEC? If the plans call for one thing and the EC installs another the AHJ is only responsible for the job being code compliant, not to make sure that the customer is getting what he's paying for. That is the customers' responsibility not the AHJ's.

In the areas I work this is exactly how it is.

Inspectors look for NEC violations the customer has to make sure they got what they paid for.

Apparently in many areas they also match the prints to the job.

 

[sceepe]

Re: The NEC vs. Engineers

I'll give you one engineer's perspective:

The AHJ should check for code compliance and safety related issues. The Engineer should check for compliance with the contract documents. He is basically a watchdog to insure the owner gets what he was promised at Bid time. (Asuuming the owner has paid for this service).

If the plans and or specs are in conflict with the NEC you should alert the Engineer. I believe both the Engineer and the Contractor have an ethical obligation to protect public safety. If that means a change order is required then so be it. But the time to notify the Engineer is when you first notice the conflict.

Now if the plans and or specs require something over and above the NEC. TOO BAD! hook it up that way. If you bid the job as per plans and specs then thats how you agreed to do it. Doesn't matter how stupid you think it is. Unfortunately, the contractor on commercial work is not involved with all the discussions leading to the design of the electrical systems. You just have to assume that there is some really good reason for the 4/0 to the ground rod.

Now to throw a wrench in this, IBC now requires special rough in inspections for contract document and code compliance. In the areas where I work, the responsibility for these is still being hashed out. From a liability standpoint I think its a nightmare for anyone other than the AHJ (who usually cant be held liable) to do the inspections.

 

[steve66]

Re: The NEC vs. Engineers

Although the inspector is only looking for code violations, be warned: the plans have been reviewed and approved prior to constructions.

Only a P.E. has the right to modify or make changes to the plans.

If you change the 4/0 to a #6, you do so at your own risk.

Steve

 

[dereckbc]

Re: The NEC vs. Engineers

It has already been said, but if the PE plans exceed NEC requirements, get over it. Because if you do not, is caught by whomever and brought to the attention of the PE, you will replace it at your expense no ifs, ands, or butt's.

 

[lady sparks lover]

Re: The NEC vs. Engineers

That NEC is a minimum, but if the ground rod is the first grounding electrode connection the in shouldn't be the minimum? If the GEC is going to the first grounding electrode, then the size per 250-66 is required even if it is a ground rod or ufer ground. All the other connections between the grounding electrodes sans except those listed in the NEC 250 are required to be 250-66.


Lady

 

[rcarroll]

Re: The NEC vs. Engineers

I review the i lines that come thru my office & many times the EE calls out a larger GEC to the rod. The 1 time I failed an energize for a #6 to the rod when a 2/0 was spec'd, the same EE wrote a letter to ok the #6, which of course is code. Go figure.

 

[raider1]

Re: The NEC vs. Engineers

The other day I had to inspect a footing on a commercial job. The prints were engineered and called for the connection to the rebar, of the ufer ground, to be exothermic welded. The electrician had installed the ufer with an approved clamp. I had to call him and tell him to either get the engineers approval for his installation or exothermic weld it. As it turned out it was less hassle to just cad-weld the connection.


Chris

 

[charlie b]

Re: The NEC vs. Engineers

Here's my take. If the plans violate code, then stop, and get it resolved. You are not free from liability if you install a code violation that I had mistakenly put on my plans. But if the plans exceed code requirements, then I probably did that on purpose. I would welcome a courtesy call. Ring me up and ask whether the 4/0 can be changed to #6. If I had a good reason, I will gladly tell you. If I missed an opportunity to save the owner some money, and if I agree that a #6 is acceptable, then I will issue a document to formally change the design.

 

[lady sparks lover]

Re: The NEC vs. Engineers

Is this a money vs. safety issue, or do you think it's overkill? Just because the code says #6, there might be other issues as to why the engineer (an engineer, like myslef, who does plans aren't necessarily an EE) put in a larger size.

I would just go with the drawing, but I've seen this happen, and the next thing you know the wires has burned up or a transformer has blown up from being over loaded, and guess who will pay...you!

 

[petersonra]

Re: The NEC vs. Engineers

the general rule you need to follow, and what almost all specs explicitly state, is that where one or more codes are in conflict, or where the spec is in conflict with a code, the more stringent provision applies.

the spec is part of your contract. just like some people might prefer one brand of switchgear over another and spec that brand. another brand is perfectly servicable, but the customer has asked and paid for what he wants, rather than what you want.

 

[sandsnow]

Re: The NEC vs. Engineers

Originally posted by petersonra:
the general rule you need to follow, and what almost all specs explicitly state, is that where one or more codes are in conflict, or where the spec is in conflict with a code, the more stringent provision applies.

That's what I was taught, however I cannot find it anywhere in writing in the building code or electrical code.

Any ideas????

 

[physis]

Re: The NEC vs. Engineers

Wouldn't that be in the commercial code Larry?

 

[petersonra]

Re: The NEC vs. Engineers

Originally posted by physis:
Wouldn't that be in the commercial code Larry?

it's also boilerplate in virtually every spec I have ever seen. the spec defines what you are contractually agreeing to provide. thus you are contractually agreeing to do it this way.

it's a commercial and contractual issue as another poster said. not a code or techincal issue.

that does not mean that you could not propose something as a seperate line item in your bid that might save the buyer some money. I don't know of anyone except government agencies that are not interested in saving some money.

for instance:

option 1: reduce grounding electrode conductors to NEC required minimum sizes. Deduct $500.

 

[highkvoltage]

Re: The NEC vs. Engineers

Here you must install what the prints show reguardless if it is overkill. Once they are stamped the only one that have changes make is the PE.