Engineer VS. AHJ

[Unbridled]

It's nice to know the NEC inside/Out. However, the majority of electrical projects have been designed by an engineer indicating wiring methods and sizing.
My question is: if an engineer over designs an electrical system such as service / feeder conduits and wiring, and I do the install per code ( smaller conduit and wiring) can the AHJ reject my installation?
Even though the installation met code, it's not what the engineer designed.:?

 

[K8MHZ]

It's nice to know the NEC inside/Out. However, the majority of electrical projects have been designed by an engineer indicating wiring methods and sizing.
My question is: if an engineer over designs an electrical system such as service / feeder conduits and wiring, and I do the install per code ( smaller conduit and wiring) can the AHJ reject my installation?
Even though the installation met code, it's not what the engineer designed.:?

The code is a minimum standard, not a design manual. An AHJ might very well be able to reject the installation because it failed to meet the design spec.

Edit to add: You may also have electrical codes that reference the NEC, but put in plain English the requirement to follow engineered plans.

 

[Smart $]

Depends on the contract. Usually, you have to install per 'approved for construction' plans. Any change requires a revision to said plans.

 

[oldsparky52]

It's nice to know the NEC inside/Out. However, the majority of electrical projects have been designed by an engineer indicating wiring methods and sizing.
My question is: if an engineer over designs an electrical system such as service / feeder conduits and wiring, and I do the install per code ( smaller conduit and wiring) can the AHJ reject my installation?
Even though the installation met code, it's not what the engineer designed.:?

I've had a discussion about his with an inspector, and his stance was that if it is an engineered job, he is inspecting it to the engineered drawings since that is what was approved for construction.

I agree with him. I would not change from the drawings unless I had a written/approved change order.

 

[steve66]

It's nice to know the NEC inside/Out. However, the majority of electrical projects have been designed by an engineer indicating wiring methods and sizing.
My question is: if an engineer over designs an electrical system such as service / feeder conduits and wiring, and I do the install per code ( smaller conduit and wiring) can the AHJ reject my installation?
Even though the installation met code, it's not what the engineer designed.:?

If the AHJ requires stamped engineering plans, its usually for a reason.

It would be kind of pointless to have an engineer design something, and to have the City review and accept it, only to have something else installed in the end.

Plans frequently have minor changes, and I don't think AHJ's should require every minor change to have an engineers approval. But service and feeder sizes I would expect to conform to the engineered drawings.

 

[dkidd]

It would be kind of pointless to have an engineer design something, and to have the City review and accept it, only to have something else installed in the end.

Welcome to my world.

 

[ggunn]

It's nice to know the NEC inside/Out. However, the majority of electrical projects have been designed by an engineer indicating wiring methods and sizing.
My question is: if an engineer over designs an electrical system such as service / feeder conduits and wiring, and I do the install per code ( smaller conduit and wiring) can the AHJ reject my installation?
Even though the installation met code, it's not what the engineer designed.:?

Piling on here...

If I were to design and stamp a set of plans, I expect the project to be installed the way I drew it. If you as the installer want to change it in the field, I expect you to contact me about it. I may or may not agree with you, but if I don't, you'd best build it to the plans as drawn because I won't be changing them. When the job is inspected, the AHJ will compare what's installed to what's in the plans, and if they don't match, the job will most likely fail the inspection.

 

[ramsy]

I don't believe engineering plans anticipate wiring methods (raceway type), or derating requirements that affect Service, Feeder, or branch wire size.

Conductor length also changes subtantially when avoiding plumbing & HVAC equipment that always block the intended raceway path for electrical.

 

[gadfly56]

I don't believe engineering plans anticipate wiring methods (raceway type), or derating requirements that affect Service, Feeder, or branch wire size.

Conductor length also changes subtantially when avoiding plumbing & HVAC equipment that always block the intended raceway path for electrical.

If the engineer knows what he is doing, all the items in your first sentence should have been taken into consideration during the design process. If there are site conditions that compel a change for the reasons described in the second sentence, they need to go in an RFI for the engineer's review and comment. You can't wing it and expect everyone to be OK with that.

 

[gadfly56]

Piling on here...

If I were to design and stamp a set of plans, I expect the project to be installed the way I drew it. If you as the installer want to change it in the field, I expect you to contact me about it. I may or may not agree with you, but if I don't, you'd best build it to the plans as drawn because I won't be changing them. When the job is inspected, the AHJ will compare what's installed to what's in the plans, and if they don't match, the job will most likely fail the inspection.

That's not the worst part. The OP is now facing two very unpalatable choices. First, rip out what doesn't conform and replace it with the required sizes of conduit and cable, or, assuming the engineer and owner will let it slide, prepare a nice fat change order to return the difference in value (value, NOT cost) between what was bid ('cause you know that the more expensive option was on the bid set) and what was supplied. Be prepared to have said change order audited within an inch of its life. I hope for the OP's sake that this was a small job.

 

[dkidd]

That's not the worst part. The OP is now facing two very unpalatable choices. First, rip out what doesn't conform and replace it with the required sizes of conduit and cable, or, assuming the engineer and owner will let it slide, prepare a nice fat change order to return the difference in value (value, NOT cost) between what was bid ('cause you know that the more expensive option was on the bid set) and what was supplied. Be prepared to have said change order audited within an inch of its life. I hope for the OP's sake that this was a small job.

OP didn't say that it had been installed, it was phrased a hypothetical question.

 

[GeorgeB]

I pretend to be an engineer and design electrohydraulic systems, very small by the standards of most here. I'm not perfect. I'm not always optimum. But my drawings are those which will be used to commission and troubleshoot the system.

I ask that proposed changes be passed by me FOR TWO REASONS. I MIGHT have a reason for my selection/action. If your preferences are as good as mine, and make something easier to install and/or less expensive, I'm all for it. However, you may not know or understand why I did something, and I need input to your variance.

BUT I absolutely need to update drawings to as-built conditions for your benefit in the future.

 

[steve66]

That's not the worst part. The OP is now facing two very unpalatable choices. First, rip out what doesn't conform and replace it with the required sizes of conduit and cable, or, assuming the engineer and owner will let it slide, prepare a nice fat change order to return the difference in value (value, NOT cost) between what was bid ('cause you know that the more expensive option was on the bid set) and what was supplied. Be prepared to have said change order audited within an inch of its life. I hope for the OP's sake that this was a small job.

In theory, the contractor would refund the difference in cost or value, but in reality, I think they usually give back about 10 cents on the dollar. And its usually tough to twist anyone's arm enough to get any more back that whatever the contractor feels like giving back.

I'm pretty sure I've seen this happen and the contractor and the general contactor still keep their 15% CO fee. I'm thinking "OK, this is your mistake, but you still want to charge a 15% Change Order fee?"

 

[Besoeker]

Depends on the contract. Usually, you have to install per 'approved for construction' plans. Any change requires a revision to said plans.

And commercial terms.

 

[gadfly56]

OP didn't say that it had been installed, it was phrased a hypothetical question.

You could be right, although I didn't read it that way. In which case, he faces two very unpalatable hypothetical choices.

 

[gadfly56]

In theory, the contractor would refund the difference in cost or value, but in reality, I think they usually give back about 10 cents on the dollar. And its usually tough to twist anyone's arm enough to get any more back that whatever the contractor feels like giving back.

I'm pretty sure I've seen this happen and the contractor and the general contactor still keep their 15% CO fee. I'm thinking "OK, this is your mistake, but you still want to charge a 15% Change Order fee?"

Larger projects will hire a cost accountant with experience in construction change orders to review the CO. They won't get away with 10 cents on the dollar. For smaller projects, anyone can get a copy of RS Means and calculate the costs to within 10% or so. After haggling on the numbers, there might be a settlement at 80% or so.

 

[Ingenieur]

I don't believe engineering plans anticipate wiring methods (raceway type), or derating requirements that affect Service, Feeder, or branch wire size.

Conductor length also changes subtantially when avoiding plumbing & HVAC equipment that always block the intended raceway path for electrical.

they better spec conduit and conductor size factoring in Vd, ampacity derating, etc. (how do you think they size it?)
and they better coordinate up to a reasonable degree

 

[Unbridled]

Under Designed

Under Designed

Thank you for all your replies.
In the past, I have simply issued a VE request to the engineer with price changes. Some get approved, some get denied.
This question is hypothetical in nature and I believe this forum has made it clear.
Thank you.

Now, another hypothetical question.

Lets say an engineer under designed a project and his design would not meet NEC requirements.
Can the AHJ fail the installation for not meeting code even though the drawings were stamped by an EE?:?

 

[Ingenieur]

In theory, the contractor would refund the difference in cost or value, but in reality, I think they usually give back about 10 cents on the dollar. And its usually tough to twist anyone's arm enough to get any more back that whatever the contractor feels like giving back.

I'm pretty sure I've seen this happen and the contractor and the general contactor still keep their 15% CO fee. I'm thinking "OK, this is your mistake, but you still want to charge a 15% Change Order fee?"

we always required a detailed breakdown and verified pricing/labor (we expected at least cost, they can keep the OH and profit if our fault...if their fault we wanted it all)
our spec had a detailed form for submitting a change order (or credit) that was part of the contract
if it was lowballing at 10%, rip it out and put it in per spec, that usually got us a revised CO with a reasonable number in return
if they refused, notify them they are in default and attach the bond

 

[Ingenieur]

Thank you for all your replies.
In the past, I have simply issued a VE request to the engineer with price changes. Some get approved, some get denied.
This question is hypothetical in nature and I believe this forum has made it clear.
Thank you.

Now, another hypothetical question.

Lets say an engineer under designed a project and his design would not meet NEC requirements.
Can the AHJ fail the installation for not meeting code even though the drawings were stamped by an EE?:?

in general, yes