I am working on a manufacturing facility that has two occupancies and is considered two buildings (office + manufacturing space). I was reviewing the code last week and found a note regarding possible AHJ clearance to treat the two buildings as one since they are occupied and managed by the same entity - it is essentially one building. This would remove the limits imposed in section 225 regarding circuits from one building feeding another. I tried to find this information again, but cannot locate it in my NEC 2020 Handbook where I could swear I had found the verbiage to begin with. Could anyone confirm what I think I had found, or did this all happen in a weird, NEC-browsing dream?
Treating joined occupancies as one, electrically
- Thread starter andrew1
- Start date
I thought it was in that section, but I distinctly remember either an exception or a Handbook annotation specifically mentioning the possibility for AHJ approval to consider multiple buildings to be "one", for all intents and purposes, electrically, which would eliminate many restrictions on passing from one building to the other.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Are the two buildings physically connected together?
Yes they are physically connected.
We will already have multiple services (1 in the office building, 2 in the manufacturing space). We were looking into this condition not because we plan to have extensive circuiting between the two buildings but because we want to avoid jumping through hoops in the case it is more expedient to feed circuits from one service or the other.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
So what is your concerns regarding Article 225?
From my understanding, they are considered two separate buildings. Would not any circuit passing between buildings be considered an "outside" branch circuit or feeder?
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
That is all that matters. You can run circuits between the two "spaces" (I will not use the word "buildings" here) all day long. I can't cite a code reference, because there isn't one. It's no different than having two subpanels on opposite sides of a standalone building, and providing power from one subpanel to a load closer to the other.
Now if you had a reason to WANT to treat the two as separate buildings, there would likely need to have some manner of fire separation (not my area of expertise). In that case, article 225 would come into play. But if the fire separation is not already present, I don't think that they can be considered two buildings.
One way to avert any 225-related issues would be to make provisions for a single feeder from the office to the manufacturing plant, and another going the other way. That would satisfy the rule about "only one outside feeder." You would not need to install either feeder (i.e., conduit, conductors, and downstream panel) right away. A conduit penitrating the joining wall, with appropriate fire stopping, would set you up for a future upgrade.
I may have used the wrong connotation of "physically connected". There will be a fire wall between the spaces. Electrically we do not want to treat them as separate buildings, but from what I understand, they will be structurally/architecturally/occupancy-wise two separate, joined buildings.
Our initial thought was, as you mentioned, to provide a single, Art. 225-compliant feed from one building to other, if needed - mostly depending on which side of this fire-rated wall the architect would like the office building electrical room. We then learned that the air handlers for the office building will be located on top of the manufacturing building roof. It was at this point that I was diving through my code Handbook and could swear I found a note regarding getting AHJ approval to treat buildings, in a similar situation as this, as electrically one. This would avoid these potential complications in sourcing and routing circuits, but it's becoming clear I must have "read" this note during a fever dream.
PD1972
Member
- Location
- New York (2017 NEC)
- Occupation
- engineer
Maybe I am wrong, but I don't think the NEC formally defines "outside", so I have always used the colloquial definition of the word to determine what is outside vs. inside.
Your buildings are physically connected so you can run everything "inside" of your building. Therefore, I don't think article 225 (Outside Branch Circuits and Feeders) applies. The scope of article 225 as defined by 225.1 is specific to outside branch circuits and feeders. It doesn't seem like you should have any concerns,
They're separate buildings, but your feeders/branch circuits are still not outside.
Sounds like this is similar to a retail plaza where you have multiple services serving tenants. I think if you think about it that way , you are thinking about the service requirements and you probably would need to group disconnects together and provide labeling , 1 of 2 , 2 of 2 service disconnects if you want to go that way , seems like it may be easier to bring one larger service on the industrial side and serve the other. The building can be designed with technically multiple building because of the occupancies using firewalls but that doesn’t need to align with multiple services
Elect117
Senior Member
- Location
- California
- Occupation
- Engineer E.E. P.E.
This might apply, but it also might not. I am not sure I completely understand what you mean by buildings.
I was working on a project where one owner bought two parcels that were connected. He applied for all of the permits and insurance as two separate parcels and addresses. They had two meters. Two services of the same voltage. In that instance it was not permitted to cross from one side to the other. In my scenario, this is a utility issue as well. If the owner subleased out one section and there was wiring between them, then all parties would need access to both services. Most businesses would consider that a security risk if there is no electrical room or if the services aren't outdoors.
If the services are different voltages and there is only one owner of both sections then that is a normal scenario to bring wiring from one area to another. You will have to pay attention to panel labeling and color codes but that is very common practice for mixed use parcels where there is a office and manufacturing taking place in the same parcel/address.
Occupancies are not the same thing as buildings. Buildings are not the same thing as parcel ownership. You are probably better asking the AHJ directly to confirm it will be okay.
I was working on a project where one owner bought two parcels that were connected. He applied for all of the permits and insurance as two separate parcels and addresses. They had two meters. Two services of the same voltage. In that instance it was not permitted to cross from one side to the other. In my scenario, this is a utility issue as well. If the owner subleased out one section and there was wiring between them, then all parties would need access to both services. Most businesses would consider that a security risk if there is no electrical room or if the services aren't outdoors.
If the services are different voltages and there is only one owner of both sections then that is a normal scenario to bring wiring from one area to another. You will have to pay attention to panel labeling and color codes but that is very common practice for mixed use parcels where there is a office and manufacturing taking place in the same parcel/address.
Occupancies are not the same thing as buildings. Buildings are not the same thing as parcel ownership. You are probably better asking the AHJ directly to confirm it will be okay.
If this is the industry standard, that would be great and make this issue moot.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
There are thousands of single buildings that have fire rated walls that does not automatically make them separate structures. It can be defined as such for certain applications like separate services but a simple firewall doesn't mean that there are multiple structures that have to adhere to Article 225.
PD1972
Member
- Location
- New York (2017 NEC)
- Occupation
- engineer
I would like to think that it is. I have yet to argue the semantics behind what is considered inside vs. outside
mtnelect
HVAC & Electrical Contractor
- Location
- Southern California
- Occupation
- Contractor, C10 & C20 - Semi Retired
I am doing an inspection now, where the owner of the property rents out space in his warehouse. In California if you change "Use of the building" you have to get permission from several different agencies again. Reginal Planning, Air Quality Management District, Fire Department and Building & Safety. They went from warehousing to paint and body without approval from the AHJ. Then they had a fire, so always check with the local authorities before you do anything.
JoeStillman
Senior Member
- Location
- West Chester, PA
I have never had a problem with calling this type of structure a single building. It's a case of your colloquial distinction running up against the code. It comes in handy sometimes to be able to call them separate buildings, but you're not required to.