Service Entrance Disconnect

[kwired]

It is very clear that you can have up to six means of disconnect for each set of service entrance conductors and that those sets of service disconnects can be at various locations on the building. How is having the sets of disconnects scattered around the building safer than having all of them, no matter how many, grouped in a single location? In the example in this thread, would it be better for the emergency responders if they could go to a single location and operate 7 disconnects, or for them to run around to 7 different locations to operate the disconnects?

Either the total number of service disconnects for a building, no matter how many sets of service entrance conductors there are, should be limited to six, or all of the the sets of service disconnects, no matter how many, should be required to be in a single location. An exception could permit remote sets of service disconnects with a sign giving the locations of all of the other sets.

I think when you have multiple occupancy buildings the building codes generally have finish rating requirements between occupancies that effectively make them separate buildings anyway, so in a way they are no different than if they were separate buildings so why not treat them like separate buildings for service entrance requirements? If you put the disconnecting means for all occupancies you are no longer treating them like separate buildings as far as the electrical supply is concerned.

So we are in agreement...??? :happyyes: As depicted, the placque is just a courtesy... but if one or more were remote to the drop, would be required, correct? Additionally, the exception does not say the disconnects must be located remote to each other or the drop in any sense, correct?

Don pretty much covered my other thoughts.

I guess so, but still fail to see that the 7th disconnect is allowed other than for fire pump, emergency systems, etc. If multiple service locations are used where permitted you are still limited to six disconnecting means per location.

 

[don_resqcapt19]

I think when you have multiple occupancy buildings the building codes generally have finish rating requirements between occupancies that effectively make them separate buildings anyway, so in a way they are no different than if they were separate buildings so why not treat them like separate buildings for service entrance requirements? If you put the disconnecting means for all occupancies you are no longer treating them like separate buildings as far as the electrical supply is concerned.
...

The fire department will not likely treat them as separate buildings if there is a structure fire (as opposed to a room and contents fire). They will want the power to the whole structure off, no matter how many buildings that the building code says the structure is.

 

[kwired]

The fire department will not likely treat them as separate buildings if there is a structure fire (as opposed to a room and contents fire). They will want the power to the whole structure off, no matter how many buildings that the building code says the structure is.

Mini mall 1/2 mile long has a fire in a store near one end of the mall. You are saying they will kill power to all stores in that mall, even the one at the farthest point away? I can see them killing adjacent occupancies to the fire if they are uncomfortable with what kind of control they have over the fire. But they may do this even if there were space between the buildings if deemed necessary. They probably at very least evacuate people from those adjacent spaces.

 

[don_resqcapt19]

Mini mall 1/2 mile long has a fire in a store near one end of the mall. You are saying they will kill power to all stores in that mall, even the one at the farthest point away?...

If it is a structure fire I would.

 

[electrofelon]

I think when you have multiple occupancy buildings the building codes generally have finish rating requirements between occupancies that effectively make them separate buildings anyway, so in a way they are no different than if they were separate buildings so why not treat them like separate buildings for service entrance requirements? If you put the disconnecting means for all occupancies you are no longer treating them like separate buildings as far as the electrical supply is concerned.

I guess so, but still fail to see that the 7th disconnect is allowed other than for fire pump, emergency systems, etc. If multiple service locations are used where permitted you are still limited to six disconnecting means per location.

One thing I would like to clear up that has had me confused reading over some of these threads is lets be clear that when we are talking about 230.40 ex #1, there is one service. Each occupancy is getting a set of service entrance conductors not a service. We could have one building, one service, eight occupancies EACH with up to 6 disconnects (at the terminus of the service entrance conductors in each occupancy). Kwired, I do agree that if you have separate occupancies you may also meet the requirements for separate buildings, however I ran in to this before and my utility would not provide a second service to the structure, and it was a can of worms with all sorts of zoning implications to get the structure split up into two "buildings" legally. I do also agree with you that the as shown in the graphic would not be compliant because there are feeders run to each occupancy not service entrance conductors. I am not entirely sure what the intent of the code writers was, but it does seem goofy to me that you can have, say, 8 disconnects scattered around the building but you cant have 8 grouped in one location. Perhaps they were thinking along the lines of what Kwired was talking about: the different occupancies potentially also making it different buildings. Perhaps they figured that if they were different "buildings" then each "building" COULD have its own service, so they might as well put an exception so that the whole structure could be fed with one service since it would be just about the same thing just with less service drops.....

 

[kwired]

One thing I would like to clear up that has had me confused reading over some of these threads is lets be clear that when we are talking about 230.40 ex #1, there is one service. Each occupancy is getting a set of service entrance conductors not a service. We could have one building, one service, eight occupancies EACH with up to 6 disconnects (at the terminus of the service entrance conductors in each occupancy). Kwired, I do agree that if you have separate occupancies you may also meet the requirements for separate buildings, however I ran in to this before and my utility would not provide a second service to the structure, and it was a can of worms with all sorts of zoning implications to get the structure split up into two "buildings" legally. I do also agree with you that the as shown in the graphic would not be compliant because there are feeders run to each occupancy not service entrance conductors. I am not entirely sure what the intent of the code writers was, but it does seem goofy to me that you can have, say, 8 disconnects scattered around the building but you cant have 8 grouped in one location. Perhaps they were thinking along the lines of what Kwired was talking about: the different occupancies potentially also making it different buildings. Perhaps they figured that if they were different "buildings" then each "building" COULD have its own service, so they might as well put an exception so that the whole structure could be fed with one service since it would be just about the same thing just with less service drops.....

Exception 1 to 230.40 does not limit us to one service.

The first sentence of the exception: "A building with more than one occupancy shall be permitted to have one set of service-entrance conductors for each service, as defined in 230.2, run to each occupancy or group of occupancies."

230.2 tells us how many services are permitted. 230.40 tells us how many service entrance conductors are permitted. They may seem like they are covering the same thing, yet they are not.

Lets look at 230.40 itself: "Each service drop, set of overhead service conductors, set of underground service conductors, or service lateral shall supply only one set of service-entrance conductors."

Maybe exception 1 really means that is being missed here is that one service drop or lateral may feed multiple multiple service locations for a multiple occupancy building. Make them separate buildings and each service must be supplied by it's own service drop or lateral. Which I guess your last sentence quoted here does kind of say what I just said.

Now the fact that a utility will or will not do something typically has little to do with NEC requirements, but zoning, easement regulations, etc. do play with what they will set as standard policies.

 

[don_resqcapt19]

What is the definition of "grouped" ?

There shall be not more than six sets of disconnects per service grouped in any one location.

If we have six service disconnects installed with 6" spacing between the disconnects and then move over a few feet and do that again, are the two sets of six grouped?

 

[kwired]

What is the definition of "grouped" ?

If we have six service disconnects installed with 6" spacing between the disconnects and then move over a few feet and do that again, are the two sets of six grouped?

That is a good question and may be subject to interpretation. What if the disconnects are 20 feet apart but within sight of one another?

A place I work at frequently had two 600 amp service disconnects right next to one another - maybe 8 inches apart. This was like 20 years ago, but we added a third 600 amp service disconnect, but there was a doorway (maybe 36" plus a few inches of wall on either side) between the existing two and the new one and it was about the only place it was going to go without a lot changes to other things. It still met all other codes primarily being the underground conductors were connected together at the source end, but landing in six or less different service disconnecting means and just how strict one is with the term "grouped" would have been a possible way to condemn that installation.

 

[don_resqcapt19]

That is a good question and may be subject to interpretation. What if the disconnects are 20 feet apart but within sight of one another? ...

In my opinion that would not be grouped.

 

[kwired]

In my opinion that would not be grouped.

Same here. But what distance is good enough to call them grouped? Less than a foot? 2, 3, 5, 10, 15? NEC only uses the word "grouped" with no exact dimension for any kind of justification.

 

[electrofelon]

Exception 1 to 230.40 does not limit us to one service.

Right, we could have something funky like two services to the building and each occupancy could have a set of service conductors from either or both services, but what I meant was a set of service entrance conductors permitted by the exception is a set of service entrance conductors and not another service. Just wanted to clarify that because my interpretation of some of the responses here is that additional sets of service entrance conductors allowed by the exception were being called "services" when they are not.

Now the fact that a utility will or will not do something typically has little to do with NEC requirements, but zoning, easement regulations, etc. do play with what they will set as standard policies.

I was just saying pointing out that there are times when it may be fortuitous to pursue 230.40 ex 1 rather than going the separate buildings route.

 

[don_resqcapt19]

Same here. But what distance is good enough to call them grouped? Less than a foot? 2, 3, 5, 10, 15? NEC only uses the word "grouped" with no exact dimension for any kind of justification.

I am looking at it from the other way...how far apart does one "group" of 6 service disconnects have to be from another "group" of 6 service disconnects so that the two "groups" of 6 are not one group of 12?

 

[Smart $]

I am looking at it from the other way...how far apart does one "group" of 6 service disconnects have to be from another "group" of 6 service disconnects so that the two "groups" of 6 are not one group of 12?

Not specified... as in there is no spacing-of-groups requirement.

Groups can?IMO?be immediately adjacent to one another as long as there is some measure of distinguishment between groups, which isn't necessarily by distance separation. Though also not specified, I'd say groups cannot be in the same enclosure unless there is at least some notable distance between groups (given listed service equipment just isn't built this way, not likely to occur, ever).