NEC 2005 Article 230.70(A)(1) Question 1

[OhioAviator]

Situation:

Small industrial facility, two-story building with two motor control centers and one 400Amp main-lug panelboard located on the second floor. Motor control centers are rated 2,000Amp main bus and are also main-lug only.

Located approximately 30 feet away from building at ground level is a 3,000KVA outdoor unit substation incorporating a GE outdoor non-walk-in switchgear lineup with six (6) AKD-10 circuit breakers. Substation is metalclad so there is no substation fence. The two motor control centers and the 400Amp MLO panel, and the underground feeder conductors serving them, are each protected by it's own AKD-10 circuit breaker in the substation. All circuit breakers are clearly marked indicating the load each serves. The substation is fed from an outdoor PowerVac switchgear lineup. All equipment is customer owned with the electric utility point of service located at the other end of the property at a pole-top recloser.


Question: Does this installation as described violate Article 230.70(A)(1) of the 2005 National Electrical Code? The local AHJ seems to think so and is asking us to replace the 400Amp MLO panel with a main breaker panel and also install a 2,000Amp main circuit breaker in each motor control center. If not, then any suggestions on how we can persuade the AHJ to change his mind?

Thanks in advance for your help.

 

[resqcapt19]

The metalclad switch gear is a structure per the Article 100 defintions in the NEC. The rule that would apply to the disconnects is not found in Article 230 for this installation. It is found in 225.31 and 225.32. Given that this appears to be an industrial installation, I would expcet that you have the documentation in place to take advantage of 225.32 Exception #1. 225.30(C) would permit the multiple feeders to the second building.
Don

 

[rbulsara]

Without scavenging the NEC pages, I would tend to agree with the AHJ. You normally can not feed one buildng from the another. Each building needs to have its own main disconncet (or group of six service disconnectes at one location), each installed (grounded) as service entrance equipment.

MLO equipment obviously do not meet the main disconncet(s) requirement. Bringing multiple feeds complicates the matter even further. Unless the building is large enough, more than one serice is typically not permitted.

 

[resqcapt19]

rbulsara,
First this building is not supplied by service conductors...it is supplied by feeder conductors and Article 230 does not apply. As far as not feeding one building from another, that is permitted by Part II of Article 225 and is very common, even for dwelling occupancies (detatched garage).
Article 225, Part II applies to this installation and in general it requires a building disconnect and a single source of supply. These rules are almost the same as in 230 for services, however there are modifications in Article 225 that do not exist in Article 230 that may permit this installation as described in the original post.
The use of multiple feeders to supply this facility is provided for in 225.30(C) because of the large capacity that is required. The case to omit the normally required building disconnects is not as clear cut, but it is permitted by Exception #1 to 225.32. The requirements to use this exception are met by may industrial applications, which I have assumed is what we have here. If the conditions of the exception are not met, then a set of grouped building disconnects would be required at the point where the feeders enter the building.
This type of installation multiple feeders and without building disconnects is common for many industrial and some campus type installations in my area.
Don

 

[rbulsara]

resqpat19:

Each building requires a main disconnect, whether it is fed from a feeder from another building or a separate service.

 

[rbulsara]

On the other hand what may be considered by the AHJ is a remote EPO station at the building with MLO board, which can readily be used to shunt trip the breakers feeding this building to remove all power in an emergency. No fire marshal will accept a buildnig without a ready means of removing power from a building in case of a fire emergency, especillay in the USA.

Again very large buildings, where multiple serices are permitted are different animals.

 

[resqcapt19]

rbulsara,

Each building requires a main disconnect, whether it is fed from a feeder from another building or a separate service.

The code does, in general, require this, but in this case there is an exception that is very commonly used that permits the omission of the building main disconnect(s) as long as the conditions of the exception.

225.32 Location
The disconnecting means shall be installed either inside or outside of the building or structure served or where the conductors pass through the building or structure. The disconnecting means shall be at a readily accessible location nearest the point of entrance of the conductors. For the purposes of this section, the requirements in 230.6 shall be utilized.
Exception No. 1: For installations under single management, where documented safe switching procedures are established and maintained for disconnection, and where the installation is monitored by qualified individuals, the disconnecting means shall be permitted to be located elsewhere on the premises.

If the conditions of the exception are met, the AHJ cannot require building disconnects unless they have local amendments to the NEC.
Don

 

[OhioAviator]

Thank you, resqcapt19 and rebulsara, for your posts. Much appreciated and very informative.

When initially confronted with this issue I defended my position using Article 225.31 Exception 1, just as resqcapt19 suggests. We have almost identical installations in other states and have had no trouble.

I also proposed an E-Stop PB on the 400Amp MLO panel and the two MCC's but the AHJ won't accept this and is sticking to his guns about applying Article 230.70(A)(1) to this situation. He's calling them services and won't back down, thereby taking away my use of 225.31 Exception 1.

The AHJ did, for a moment, entertain 225.31 Exception 1 but then backed away. We have lock-out/tag-out procedures written for every piece of equipment on site, including the electrical power distribution system, but the AHJ refused on the grounds that we do not have any maintenance electricians (qualified persons) employed at the site and instead rely on an outside electrical contractor on call.

Any other ideas would be appreciated, otherwise I'll be spending more than $25k to comply.

Again, thanks!
John

 

[rbulsara]

If AHJ wants it, you have to provide it and I think his request is reasonable. Any other ideas are of no use.

Regarless of codes, not having a main disconnect is a bad design. I never promote a bad desgin.

 

[resqcapt19]

If AHJ wants it, you have to provide it and I think his request is reasonable. Any other ideas are of no use.

That is not correct, the AHJ cannot legally require anything that is not required by the codes that his unit of government has adopted. As far as good design, the use of this exception for industrial and campus type installations is very common. Under the conditions in the exception, it is very likely that facilities personel will be at the site of any emergency proir to the arrival of the fire department or other government provided emergency service.
Don

 

[HCBFlash]

The AHJ is just that. Do you know ALL of ALL the codes and exceptions taken to them by the AHJ,,, (and I don't mean the inspector)?

The NEC is not the final authority, and I pray it never will be.

If this situation bugs you enough, get involved with the CMPs, and other politics, if nothing else you can get a new article or section written for you!