David Calao

We have a 1600 Amp service that was comming directly from the Utility Transformer to a Pull Box and being split into (2) 800 Amp Fused Disconnects. We are the contractors as well as the engineers for this project. We designed (4) sets of 750 MCM AL (THHN) the conductors were terminating on the Utility Transformmer with Two-Hole Long Barrel Crimp Lugs UL rated at 90 Degrees and indoors at a Pull Box (standard Nema 1 sealed by Utility) with Ilsco Power Distribution Blocks also UL rated for 90 Degrees. If the lugs on both Ends are rated at 90 degrees why can't I use the 90 degree column in 310.16? This is not a manufactred switchgear where there UL Listing would restrict the Lug rating to 75 Degree. The inspector is insisting I use the 75 Degree Column and add a set of Conductors.

John Valdes

THHN is 90 degree wire also. I would not know why this would be required. It looks like you are compliant. IMO.

brian john

Whats the rating of the equipment where the final ternminations are made?

nick

do not take this as a answer to problem , you said lugs are rated for 90 c is the gear the breakers the transformer itself ul listed as a 90 c .meaning the whole piece of equipment , read artical 110.14 electrical connections part c (1) equipment provisions , also fpn note( 2) , the equipment is the key words in the code , but the lug by itself is not going to help with the transfer of heat meaning the breaker or transformer buss if it is not 90 c ul rated its a issue . even the metal frame of the switchboard must be 90 c ul rated . you can get your engineer or your equipment manufacture to sign off ,meaning a letter to inspector to clear his part so you take full responsibilty , he will pass .if not your going to have a issue .take care best to ya .

ralph

Nick is correct. I had the same thing happen, and it came to UL listing in the ahj's mind.
If I recall, he would only let me have 1560 in amps.
I had a fused 1600, so I got 1500 a fuses.

Raverill

The Authority Having Juristiction, AHJ, the inspector, has the final say. If you are working with an inspector you don't know, especially on a project the size you describe, it's good politics and good business to go over the project with the AHJ before you start. This 20 minute "consultation" will cost a few bucks in extra fees, but it can save you a lot more in extra costs and delays. Most inspectors are happy to do it. It makes life easier for them as well.
You can fight the inspector but even if you win your battle you will always have a hard time dealing with him.
You are left with three optons;
1. Add another set of aluminum conductors.
2. Change to copper conductors.
3. Reduce the service ampacity.
I don't know the particulars of your situation to know what will cost the least.

Good electrical design always leaves room, never going to the max. Never fill a new panel, never load conductors to the max, always design with the lower temp rating.

gilbequick

I see this as a big problem with the way many people in the trade think. The inspector IS NOT THE AHJ. He represents the AHJ and enforces their rules. He just can't make things up as he goes along because he thinks that's what correct. I once had an inspector tell me to do something in a certain way and it was something I'd never read or heard before, so I asked him if he could help me to better understand it and give me a code reference so I could look it up. He said to me, "Ohh it's not in the code book, I read it in ECM magazine last month." GOOD GREIF MAN come on! I called the building dept on that one and they overrulled him.

People, quit bending over backwards to appease these big headed inspectors who think they can do as they please. They have rules to follow to, even if some of them think they don't.

Raverill

I didn't say you can't go over the inspector's head, I said you are likely to be sorry if you do. I worked for a contractor who went ovr the inspector's head to the chief inspector of a medium sized city and won the argument. However he made an enemy of the inspector and it was no longer worth it to do work in his district. If you've worked with the inspector before and are on good terms with him, fine. If you've never dealt with him before, you could be asking for trouble. That's why I suggest a conference with a new inspector before work is done.

brian john

Horse Hockey, IF an inspector is enforcing his own code and you do nothing to stop it, you are allowing a wrong to continue against all involved in the trade including the owners of the building. If the inspector gives you a on going hard time that GET HIS JOB, cause he is no inspector.

As for trying to have a conference with your inspector, I guess that depends on where you work. We work in 14 different jurisdictions regularly. Trying to get an inspector for an inspection is tough much less for a friendly chat. The code is the code and should be enforced as that.

BUT if you were to do as the OP did I think an approved set of drawings would have avoided this issue. Many jurisdictions around here require a drawing for changing a wirenut.

nick

i agree with the drawns brian ,most of our work must be submitted to the county 6 months before we start work , if the electrical meaning are installed work in the field does not match the drawns it will not pass .if there was a engineering problem like a wrong feeder size or conduit size or breaker size ,meaning a error we[ rfi /rfq ] it to the [ engineer / art] who then gives us new direction and a new drawning or bulletin to change the wrong . i say if you installed the work per the drawns as brian said , then get your engineer to correct the issue , or go by the nec . because in this case the inspector is correct if what i see in your post .or if you want take the rating plug out put lower one in . got a question is this a underground or overhead ? the alu wire that size is usaully [ dual rated ]wire meaning its 90 c 75 c dual rated. if that doesnt help try this [ underground feeder ] the code says it does not get derated ? but its a certain distance. read 310.15 b 2 exception 4 . but ill put my money on that dual rated wire look at that jacket it will say 75 /90 ? you dont need to derate you only count the abc not neutral ?[ 310.15b 4 ] check it out you may have options best to ya

nap

how do you even come up with being able to use THHN outside? It needs to be THWN or is this wire dual rated, by chance? If so, you must use the proper wire rating, THWN, since it is outside and must be rated for wet conditions which just happens to have a 75º rating.

and to gilbequick;

the inspector IS the AHJ. He has the authority to make those judgement calls or interpretations of the code. In some areas, there is an office to appeal to but in my area, the only appeal is to the state so the inspector is the AHJ, hands down, no questions.

nick

ya nap dual rated [thhn/ thwn] wire we use it on all our jobs overhead and underground .i was thinking he may have it and didnt know what he had overhead or underground as its not defined in his post ? we get our wire from many areas but look up usa wire cable and you will see dual rated thhn thwn 75 /90 rated feeder conductors .been around for a long time . let me add that the electrical engineer has option to overide the electrical inspector at least were i work if he makes a call in writing its pretty much set , or the manufactor of the gear like ge or westinghouse . we get in colors now all so that dual wire . iam trying to help this poor guy out of a fix its going to cost him lots of money so iam thinking of everything that i know to help him with his issue , best to ya

JohnJ0906

WRONG, at least here.
The inspector is the representative of the AHJ, not the AHJ himself.
The AHJ is defined by the law that adopts the NEC in a particular area.

__________________
John from Baltimore
"One day at a Time"
All responses based on the '08 NEC
It's not my fault, it's not my problem, I'm not your solution.

ralph

You nailed it. Gilbequick, You are quick to lay the hammer on the AHJ, but do you really know that they , most often than not , are the final say. If you ever pulled that stuff with me , and I was an inspector , you would be hard pressed to ever get an inspection. A lot of jusidictions are different, and they usually have the final say. Unfortinatly, ( sp ?) youv got to roll with it sometimes to get the job done

nap

yes, if you notice, the thhn is 90 deg rated and the thwn is only 75 degree rating. If this is outside, it is going to have to be wet rated so that means the thwn is the designation that is used in this situation which means 75 deg ratging. Overhead or underground is going to be a wet location.

an electrical engineer has no rights to override an inspector...period, in any jurisdiction that the inspector is the AHJ. We have state stamped jobs all the time but when the inspector walks in, do you want to guess who has the power? I'll give you a hint; it's not the engineer that stamped the thing.

as to the gear; as long as it is UL listed, the AHJ has no authority to alter that unit as long as it is being used as listed and it is proper to use it in the situation it is.

nap

it sounds like an argument over semantics. I would guess that the inspector has control of the situation and has the authority to make decisions, right? If so, he is the AHJ. Of course he represents a bigger entity. Even in the 2 states I deal with, the inspector does not have final say but to protest the inspectors call, you have to appeal to the state board. The local inspector does get to make decision and judgement calls so he is the AHJ.

BTW; the AHJ is defined in the code.

the organization, office, or individual responsible for approving equipment, materials, an installation, or a procedure.

Sure sounds like an inspector to me.

nap

Hopefully to head off an argument over this, I do agree with gil on this situation. An inspector, in any jurisdiction I am aware of, cannot make code. He can only enforce code BUT he does have the authority to interpret the code. He does have to be able to cite code to support his call BUT he does get to interpret that code. If you have an arguement with him, you must appeal to a higher power, whoever that may be.

nick

so that dual wire doesnt help its only good for 1540 amps ,unless he down sizes his fuses or breakers or rating plug in his gear ? or pulls out what he has and pulls in as said copper ? i have a question what is dual rated wire good for if you must use the 75 degree column in nec anyway . why do they make it if its 90 deg or 75 deg / and a crossed link jacket you would think it had a purpose that they made it ? and if its rated for both it should be able to cover both temps at 90 degree if not than its not a safe jacket in my book . so at 90c higher temp the thwn insulation should melt down is that what the nec thinks ,here yet is another part of the code thats not clear to me , i understand it but i just dont understand how they come up with some of the rules . ill look into dual wire more theres a fine line to why they designed it and i need to know why .its misleading to me . today they make dual rated lugs and dual rated panel boards and dual rated wire . so how does the code restrict this case what column would one use if you have all three installed ? wet or dry 90 or 75 ? i guess the wet area would only cover the thwn part but thhn would be only the dry part , i think the code needs to be up dated to whats going on today not three years behind the times ,thats my thinking on this subject . any comments from the nec ?or how about the company that makes the dual rated stuff give me some input on why you sell this stuff if it cant be used and to me its bad advertising/ misleading .but i maybe out of line and if i offended anyone iam sorry its just me, but you can comment ,or request a appeal to this post ?best to ya take care

brian john

And if an inspector pulled that with me he would be out of a job.

The system of having the ability to go over an inspectors head is set up to stop a small person with to admit they MAY have make mistake or are FLAT WRONG or they could be right. If an inspector is good at what he does he should have no problem being questioned. Only an insecure person would take revenge.

There are levels of protection set up by many states to stop inspectors from writing their own code this protects the state, county EC and customer from unfair interpretations that could cost all money and also protects the all from EC trying to circumnavigate the NEC.

JohnJ0906

Around here, thank God, it is specifically defined as the building official.
Yes the inspectors are his reps, and, yes, they do make interpretations, but they are not the final say, if we electricians so choose.

Would you let an inspector cost you $100 by being wrong? $1000? $10,000?

Had to make a phone call to an inspector about the depth of a trench that he failed. He had misread table 300.5. I called him and we looked at it together, and he admitted he was incorrect, and passed me.

I guess you would have just redone that 200' trench? No thanks.

__________________
John from Baltimore
"One day at a Time"
All responses based on the '08 NEC
It's not my fault, it's not my problem, I'm not your solution.