ATS feeder question

[Smart $]

...Let's consider the suggestion made to energize the proposed equipment from building #2...

Let's not!!!

You cannot run building #2 service-supplied power to building #1.

 

[twinman]

Thoughts

Thoughts

I've reviewed all the sections that have been posted in the thread various times.

My interpretation is that it not prohibited as per 225.30(A)(4) and (6).

The equipment falls under article 702. As such, article 702.6 requires the transfer equipment to be suitable for the intended use and designed and installed so as to prevent the inadvertent interconnection of normal and alternate sources of supply in any operation of the tranfer equipment.

Either the existing installation in building #2 and the proposed installation meet this requirement. Neither of them permit operation in parallel with the normal source. Consequentely, article 705 does not apply.

Regarding the post to consider connection to bldg #2, the question is can the existing duct bank which has feeders and branch circuits from bldg #1, be utilized to run a feeder which originates in bldg#2?

Note: The feeder will not run from bldg #2 through bldg #1 to duct bank. Rather it will run from bldg #2 to duct bank and thus share the duct bank with bldg #1 only.

 

[don_resqcapt19]

I am uncertain also, but as I have read and reread it for just this case, I don't see where the means utilized is prohibited. The term transfer equipment does not directly define the equipment as being a single, integral unit.

My issue is the fact that you can manually force the outputs in the PLC to have both breakers on at the same time.

 

[Smart $]

My issue is the fact that you can manually force the outputs in the PLC to have both breakers on at the same time.

Perhaps. I am not certain exactly how the PLC controls the breakers. What if a PLC output controlled only a relay/contactor with NC/NO circuits, mains on say N.C., and generator breakers on N.O? Under this condition it would be impossible to use the PLC to force both supplies on at the same time.

 

[Smart $]

Regarding the post to consider connection to bldg #2, the question is can the existing duct bank which has feeders and branch circuits from bldg #1, be utilized to run a feeder which originates in bldg#2?

Note: The feeder will not run from bldg #2 through bldg #1 to duct bank. Rather it will run from bldg #2 to duct bank and thus share the duct bank with bldg #1 only.

First thing to consider is that running feeders and branch circuits in the ducts is more dependent upon the originating power source than what building they come from or end up at. Anyway you go about it, you cannot run service-supplied-power conductors between building #1, service #1 and building #2, service #2, except under highly restrictive and special conditions.

If you are talking about a feeder supplying only power from the standby generator, you can run it wherever you please ( but still subject to condiitons of normal wiring methods, though).

 

[slick 50]

Don,

The proposed equipment is a motorized gate. It is to be located at the demarcation between secure and unsecured area in an alternate access point.

As such, I assume that the installation is governed by 702.8 rather than 700.9
Consequentely, emergency and general wiring could occupy the same conduit, etc. Correct?

Thank you.

just run the gate off of the other building that has backup power.:grin:

 

[Smart $]

just run the gate off of the other building that has backup power.:grin:

Have you read the whole thread?

Summary (from my point of view):

Each of the two buildings has a service. IIRC, the buildings are even on separate properties but have the same owner.

You can't run normal power from the building with backup to the building that don't.

You can run backup power from the building that has it to the building that don't.

Unless you use normal power from the building that don't have backup, you'd have to run the generator every time the gate is operated.

 

[slick 50]

Have you read the whole thread?

Summary (from my point of view):

Each of the two buildings has a service. IIRC, the buildings are even on separate properties but have the same owner.

You can't run normal power from the building with backup to the building that don't.

You can run backup power from the building that has it to the building that don't.

Unless you use normal power from the building that don't have backup, you'd have to run the generator every time the gate is operated

.

Thats what I meant. Run the circuit from the building that does have backup. When utility power is present, the gate will run withour generator. When utility is out, the generator will run the gate.

 

[Smart $]

Thats what I meant. Run the circuit from the building that does have backup. When utility power is present, the gate will run withour generator. When utility is out, the generator will run the gate.

OK... if by "Run the circuit from the building that does have backup" means a powered-by-generator-only circuit...

...but I think we already figured that part out

 

[twinman]

Power from blg#2

Power from blg#2

Connection to an adequate source in bldg #2 (in the event of utility power failure, the whole building is connected to standby emergency power) would eliminate this whole issue. However, the existing ductbank must be utilized.

There must be some kind of safety issue involved, that is, if maintenance personel access the manholes, how will they know which feeder is from where? When service #1 is dead, they might assume that all ductbank is "dead", but that is hardly the case. The feeder connected to the stanby emergency generator (in bldg #2) is "live".

OSHA may rule out the connection to bldg#2. Article 702.9 allows optional standby system wiring to occupy the same raceways, cables, boxes, and cabinets with other general wiring. I interpret that it applies to normal and optional stanby power from the same building or structure.

Article 225.30 has been quoted previously and ensurability that normal and stanby power are not simultaneously connected, but my understanding is that (A) Special Conditions allows for additional feeders or branch circuits to supply optional stanby systems and systems designed for connection to multiple sources of supply for the purpose of enhanced reliability.

This appers to be a complex issue and I am not quite sure we got a conclusive answer based strictly on NEC.

 

[Pierre C Belarge]

The issue is you are not providing a transfer switch for Bldg #2 to transfer power from the utility to the generator. You are trying to use a PLC for that function. 702.6

 

[twinman]

Transfer switch

Transfer switch

Pierre,

I am not refuting the validity of your stament, but section 702.6 is Transfer Equipment. An automatic transfer switch certainly falls within that category, but not exclusively.

I am yet to receive information on the existing stanby system configuration, but what is the exact concern with utilization of a PLC? If the stanby system was approved by AHJ, including the PLC, is the issue that the utility and the stanby power are not paralleled under any circunstance? How can it be verified?

 

[Smart $]

The issue is you are not providing a transfer switch for Bldg #2 to transfer power from the utility to the generator. You are trying to use a PLC for that function. 702.6

I second twinman's position in that a transfer switch certainly qualifies as transfer equipment, but not exclusively.

 

[augie47]

In this jurisdiction, POCO would have to be convinced and I have sincere doubts. They don't like some panel interlocks as they are plastic.

 

[Pierre C Belarge]

I was not clear in my statement, I also agree the section deals with transfer equipment. What I was saying is the PLC is not (as I see it) transfer equipment.

Yes, I am concerned that the utility and generator conductors may be energized at the same time.

 

[ceb58]

I was not clear in my statement, I also agree the section deals with transfer equipment. What I was saying is the PLC is not (as I see it) transfer equipment.

Yes, I am concerned that the utility and generator conductors may be energized at the same time.

I think the question is (the good old standby) is this PLC set up listed and approved for transfer equipment? Or is it some invention of someone who had some spare parts laying around?

I do agree with the fact that the circ. from build.2 cannot be installed in the duct bank with build.1 wireing. As was said think of some one working on the duct bank thinking every thing was dead. Or if there were a short between the wireing you then could back feed the utility.

Just go to the gate install an inverter, battery and a solar charger:grin:

 

[Smart $]

I was not clear in my statement, I also agree the section deals with transfer equipment. What I was saying is the PLC is not (as I see it) transfer equipment.

Yes, I am concerned that the utility and generator conductors may be energized at the same time.

I think the question is (the good old standby) is this PLC set up listed and approved for transfer equipment? Or is it some invention of someone who had some spare parts laying around?

I do agree with the fact that the circ. from build.2 cannot be installed in the duct bank with build.1 wireing. As was said think of some one working on the duct bank thinking every thing was dead. Or if there were a short between the wireing you then could back feed the utility.

Just go to the gate install an inverter, battery and a solar charger:grin:

Transfer equipment under Article 702 only has to be approved (ref: 702.4) and not required to be labeled, listed, or otherwise required to meet any third party standard.

At this point, can we assume the existing transfer means is designed and installed so as not to inadvertently cause interconnection of normal and alternate sources in any operation of the transfer equipment. I understand we have no way of verifying this one way or the other, but this possibility is not at the gist of the thread topic.

 

[dbrejda]

ATS Feeder Question

ATS Feeder Question

At least three issues; Are either or both ATS service rated? If not, OCP needed in utility feeder at which ever one(s) are not.

You may need 4-pole ATS to switch neutrals. Otherwise you may have parallel neutrals through the generator wiring. ATS would also need to be open transition. Some ATS will sync with and parallel the utility, even briefly, when going back (closed transition).

Is generator large enougn to run both loads at the same time?

Another issue may be what happens when the owner sells one of the buildings.

My gut feeling is this is not a good idea. But as the code says, it's up to the AHJ.