Applying NEC to 46kV substation designed to NESC

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GoldDigger

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Staff member
Location
Placerville, CA, USA
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Retired PV System Designer
Fair enough.
The city can review to NEC. Then under the contract the responsibiilty for constructing to NESC is on the contrractor(s) hired by the PV company and the responsibility for inspecting it for NESC compliance is on the utility before accepting it.
Once it has been accepted by the utility, they are responsible for keeping it in compliance with NESC, which is both a construction and a maintenance standard.
If the utilty abandons its burden to inspect it for NESC compliance (trusting the designing PE completely), the responsibilty for any safety problems falls on them. And they are, i suppose, subject to review by the utiltities commission once it is put into service. The utility also would have to ensure NESC compliance to satisfy OSHA (too late by the time an accident occurs, but worth pointing out to POCO.)

The city can attach a disclaimer to their NEC approval stating explicitly that no inspection was made for compliance to NESC.
 

Joe.B

Senior Member
Location
Myrtletown Ca
Occupation
Building Inspector
How about this, let the city plan reviewers do their plan review to make sure nothing violates the NEC, at the same time send a set of plans to a third party reviewer to make sure the plans comply with NESC. That way whoever does the inspections can follow the plans and know that there are no violations with either code.
 

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
The verbage is too specific in the NEC. Facilities under the direct control or own by public utility. My situation, the owners of the PV facility are building for the public utility. Not under the direct control or owned by the public utility yet. The power purchase agreement between the two parties stipulates the substation will be built to the public utilities standards before it is deeded over to the public utility. Exact same end product for the public utility facility, but different circumstances during construction. I got Corporation counsel involved and they made the determination the NEC exemption is not eligible. Thanks for link.

Could NEC Article 691 apply in your case since the installation would be "not under exclusive utility control" until it was deeded to them (assuming it's 5000 kW or larger)? I'm not a legal expert, but I think the utility is still exercising at least partial "control" before the deeded transfer occurs because it is stipulating and has ownership of the standards to which the substation must be built.

"691.1 Scope
This article covers the installation of large-scale PV electric supply stations with an inverter generating capacity of no less than 5000 kW, and not under exclusive utility control."

691.6 Engineered Design, and 691.7 Conformance of Construction to Engineered Design describe stamped design and other documents required to be provided upon request to the AHJ.
 
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The word "safe" keeps coming up. We have two possible codes- the National Electrical Code, which is a fire prevention code (from the National Fire Protection Assn), and the National Electrical Safety Code, which "sets the ground rules and guidelines for practical safeguarding of utility workers and the public during the installation, operation, and maintenance of electric supply, communication lines and associated equipment."

Trying to apply the NEC to this is like trying to play baseball using the rules of cricket.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
The verbage is too specific in the NEC. Facilities under the direct control or own by public utility. My situation, the owners of the PV facility are building for the public utility. Not under the direct control or owned by the public utility yet. The power purchase agreement between the two parties stipulates the substation will be built to the public utilities standards before it is deeded over to the public utility. Exact same end product for the public utility facility, but different circumstances during construction. I got Corporation counsel involved and they made the determination the NEC exemption is not eligible. Thanks for link.
I think you need to go back to the lawyers and show them the the parts of the NEC itself that would allow alternative methods and that would justify signing off on an NESC compliant design that is stamped by an engineer, provided the installation meets some due diligence called for in the NEC. Or don't even go back to the lawyers, and just declare that that's your interpretation of the NEC. 90.4 paragraph two, you may 'waive specific requirements in this Code or permit alternative methods where it is assured that equivalent objectives can be achieved..." The 'alternative methods' that achieve the same objectives, broadly speaking, are the NESC, which is intended and widely used to ensure the safety of similar installations. Apply 490.48 and 691.6 as applicable, and inspect to those sections and the engineer's specs. Hire an NESC qualified inspector as a special consultant to join you for inspection. There are things you can do. The answer to your original question "Is it possible to review a 46kV substation under the NEC but the substation was designed to meet NESC?" is yes.
 

mrktaylor7

Member
Location
Hawaii
Occupation
Urban planner
I think you need to go back to the lawyers and show them the the parts of the NEC itself that would allow alternative methods and that would justify signing off on an NESC compliant design that is stamped by an engineer, provided the installation meets some due diligence called for in the NEC. Or don't even go back to the lawyers, and just declare that that's your interpretation of the NEC. 90.4 paragraph two, you may 'waive specific requirements in this Code or permit alternative methods where it is assured that equivalent objectives can be achieved..." The 'alternative methods' that achieve the same objectives, broadly speaking, are the NESC, which is intended and widely used to ensure the safety of similar installations. Apply 490.48 and 691.6 as applicable, and inspect to those sections and the engineer's specs. Hire an NESC qualified inspector as a special consultant to join you for inspection. There are things you can do. The answer to your original question "Is it possible to review a 46kV substation under the NEC but the substation was designed to meet NESC?" is yes.
Thank you for this detailed response and answering if all electrical related components of a 46 kV substation could be comprehensively reviewed under the NEC. I was thinking there may be high voltage components that simply are not adressed in the NEC. I'm going to make a recommendation that will incorporate a lot of what you covered about using an outside party to assist with review and inspection to NESC. Your statement "the due diligence called for in the NEC" is maddening. Crazy that you need to use two different codes to get the best result, considering the NESC was created for that one purpose. Getting lawyers involved from the utility company and city is what started this crap show.
 

mrktaylor7

Member
Location
Hawaii
Occupation
Urban planner
Fair enough.
The city can review to NEC. Then under the contract the responsibiilty for constructing to NESC is on the contrractor(s) hired by the PV company and the responsibility for inspecting it for NESC compliance is on the utility before accepting it.
Once it has been accepted by the utility, they are responsible for keeping it in compliance with NESC, which is both a construction and a maintenance standard.
If the utilty abandons its burden to inspect it for NESC compliance (trusting the designing PE completely), the responsibilty for any safety problems falls on them. And they are, i suppose, subject to review by the utiltities commission once it is put into service. The utility also would have to ensure NESC compliance to satisfy OSHA (too late by the time an accident occurs, but worth pointing out to POCO.)

The city can attach a disclaimer to thr NEC approval stating explicitly that no inspection was made for compliance to NESC.
My w
How about this, let the city plan reviewers do their plan review to make sure nothing violates the NEC, at the same time send a set of plans to a third party reviewer to make sure the plans comply with NESC. That way whoever does the inspections can follow the plans and know that there are no violations with either code.
This is generally how things should functionally work. However, the city currently has no authority to govern the NESC. However, a commentor on this thread referenced a section in the NEC about alternative design which may fill this gap.
 

mrktaylor7

Member
Location
Hawaii
Occupation
Urban planner
The word "safe" keeps coming up. We have two possible codes- the National Electrical Code, which is a fire prevention code (from the National Fire Protection Assn), and the National Electrical Safety Code, which "sets the ground rules and guidelines for practical safeguarding of utility workers and the public during the installation, operation, and maintenance of electric supply, communication lines and associated equipment."

Trying to apply the NEC to this is like trying to play baseball using the rules of cricket.
What you said is how I have been understanding my current situation 100%. It appears the NEC code can be used to review the substation but it won't have all the standards specific to Interconnection Facilities to ensure safety. Also, it works backwards, you would never want to use the NEC as a guide to designing a substation, why would you use it to review it? To make things murky, a commentor indicated there are due dillegence components found in the NEC that should probably be in the NESC. Your analogy is spot on.
 

mrktaylor7

Member
Location
Hawaii
Occupation
Urban planner
Could NEC Article 691 apply in your case since the installation would be "not under exclusive utility control" until it was deeded to them (assuming it's 5000 kW or larger)? I'm not a legal expert, but I think the utility is still exercising at least partial "control" before the deeded transfer occurs because it is stipulating and has ownership of the standards to which the substation must be built.

"691.1 Scope
This article covers the installation of large-scale PV electric supply stations with an inverter generating capacity of no less than 5000 kW, and not under exclusive utility control."

691.6 Engineered Design, and 691.7 Conformance of Construction to Engineered Design describe stamped design and other documents required to be provided upon request to the AHJ.
Thanks for the code reference. Having different ways to address this will be good
 

Joe.B

Senior Member
Location
Myrtletown Ca
Occupation
Building Inspector
My w

This is generally how things should functionally work. However, the city currently has no authority to govern the NESC. However, a commentor on this thread referenced a section in the NEC about alternative design which may fill this gap.
Well maybe there's more going on here than your letting on to, I was under the impression that you were representing the city in this situation, but maybe that's not the case. Things are different state to state so I can only speak to how I would do things if it were in my jurisdiction. What I hear you saying is that the city "can't" review under NESC because it hasn't adopted that code. The city should be concerned with safety and would be fully within their authority to review plans beyond the scope of adopted codes which is why I suggested they do their NEC plan review, and concurrently hire a third party to review for NESC (SAFETY) compliance. Since building departments exist to protect life and safety than this should not be a stretch by any means.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Well maybe there's more going on here than your letting on to, I was under the impression that you were representing the city in this situation, but maybe that's not the case. Things are different state to state so I can only speak to how I would do things if it were in my jurisdiction. What I hear you saying is that the city "can't" review under NESC because it hasn't adopted that code. The city should be concerned with safety and would be fully within their authority to review plans beyond the scope of adopted codes which is why I suggested they do their NEC plan review, and concurrently hire a third party to review for NESC (SAFETY) compliance. Since building departments exist to protect life and safety than this should not be a stretch by any means.
City building departments only have the authority to require what the law says they can require. They can't just make it up as they go.
 

mrktaylor7

Member
Location
Hawaii
Occupation
Urban planner
You are both correct. Just following the rules and not thinking of public safety is irresponsible and the City needs legal authority to enforce codes. The city needs to create a legal pathway to requiring an NESC compliance review and it will probably be through 3rd party. I don't mean to mislead on this question, I am representing the city side, this issue is overly complicated. My guess why, old codes not adapting to new trends. Private substations are becoming more commonplace, especially with renewables.
 

Joe.B

Senior Member
Location
Myrtletown Ca
Occupation
Building Inspector
City building departments only have the authority to require what the law says they can require. They can't just make it up as they go.
Absolutely correct and most departments adopt some version of building code based off of ICC. There are provisions in the administrative sections of code that address fire and life safety. No code official should be just going about willy-nilly and doing whatever they want, but they should be concerned about life safety and the intent of code is to support such actions. The case presented here is a perfect example and a responsible code official should be looking at ways to protect their community and the people who may have to work on said installations. Just as an example of some of the code sections that exist for code officials to use to protect life safety I copy pasted a few sections below.

[A] 101.3 Intent

The purpose of this code is to establish the minimum requirements to provide a reasonable level of safety, public health and general welfare through structural strength, means of egress facilities, stability, sanitation, adequate light and ventilation, energy conservation, and safety to life and property from fire, explosion and other hazards, and to provide a reasonable level of safety to fire fighters and emergency responders during emergency operations.

[A] 104.1 General

The building official is hereby authorized and directed to enforce the provisions of this code. The building official shall have the authority to render interpretations of this code and to adopt policies and procedures in order to clarify the application of its provisions. Such interpretations, policies and procedures shall be in compliance with the intent and purpose of this code. Such policies and procedures shall not have the effect of waiving requirements specifically provided for in this code.

[A] 107.1 General

Submittal documents consisting of construction documents, statement of special inspections, geotechnical report and other data shall be submitted in two or more sets with each permit application. The construction documents shall be prepared by a registered design professional where required by the statutes of the jurisdiction in which the project is to be constructed. Where special conditions exist, the building official is authorized to require additional construction documents to be prepared by a registered design professional.
 
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