Outside main disconnect

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mtaylor

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Sorry if this is a repeat.

I am having trouble trying to understand what requirements need to be met in order to eliminate the need of an outside main disconnect switch. I have seen several projects where the secondary from the POCO transformer comes straight to a C.T. Cabinet or meter and then to the MDP inside of the structure. Also, the MDP is not always located in a room that is near an exit. I've also seen several jobs pass inspection this way. Another thing, does a pad mount transformer differ from a pole mount transformer where this is concerned? I don't see why it would but this question has come up and would be interesting to know why if so.

Thanks!
 
NEC 2008 230 Services --- 230.70 Disconnecting Means ( A ) Location ( 1 ) Readily Accesible Location: either outside OR inside at the nearest point of entrance of the service conductors. Nearest point of entrance is not plain so that will be determined by the AHJ for your area. Tennessee says 2 ft of pipe inside the structure wall is max.
 
Just for the concept, the metering equipment is just a wide place in the conduit where we put our cash register (meter) and is not considered to be service equipment. Ignore the cash register when starting your project and locating your service equipment.

First, go to 230.70 for the location of service equipment. This section will give you the rules for where the service disconnecting means must be be placed. Just as important is 230.6 that tells you what is considered to be outside a building.

There is nothing that requires the main disconnecting means to be located close to an exit. Additionally, the source provided by the serving electric utility has nothing to do with any of this except as spelled out in their requirements for electric service.

Please keep in mind that this is written in broad strokes and there are a lot of nuances. :smile:
 
"Cash Register"

"Cash Register"

Hello Charlie,
I am having a difficult time finding the definition of "Cash Register" in the NEC. I have looked in Articles 100 and 230 with no luck.
Can you help?
 
goodcode said:
Hello Charlie,
I am having a difficult time finding the definition of "Cash Register" in the NEC. I have looked in Articles 100 and 230 with no luck.
Can you help?
Click to expand...

I'm sure Charlie is talking about the meter that reads your usage and you are billed accordingly. Thus the term cash register. :0)
 
mtaylor,

Another point that may clear up some of your questions: 230.6 lists cases where conductors are not considered as being inside the building. Item (1) is conductors installed under at least 2 in. concrete under a building. The service conductors could be brought in under a 2 in. slab and come up into a disconnect located in a room away from the exterior walls of the building and the disconnect still be considered to be located "nearest the point of entrance" of the conductors.
 
jamesoftn said:
NEC 2008 230 Services --- 230.70 Disconnecting Means ( A ) Location ( 1 ) Readily Accesible Location: either outside OR inside at the nearest point of entrance of the service conductors. Nearest point of entrance is not plain so that will be determined by the AHJ for your area. Tennessee says 2 ft of pipe inside the structure wall is max.
Click to expand...

Depends where in TN. In Shelby county we are allowed 15' "as the crow flies" so to speak before a disconnect is required.
 
Hello Goodcode

Hello Goodcode

goodcode said:
. . . Can you help?
Click to expand...
Hello Jimmy and greetings from Dothan, AL. Golf is great and I am on my way to TX next.

The definition of cash register is reflected in Webster's 11th Collegiate Dictionary, the official dictionary of the NFPA. A person with your knowledge should have known to go there after failing to find the definition in Articles 100 and 230. :D :)
 
eprice said:
mtaylor,

Another point that may clear up some of your questions: 230.6 lists cases where conductors are not considered as being inside the building. Item (1) is conductors installed under at least 2 in. concrete under a building. The service conductors could be brought in under a 2 in. slab and come up into a disconnect located in a room away from the exterior walls of the building and the disconnect still be considered to be located "nearest the point of entrance" of the conductors.
Click to expand...

If this is the case I feel sorry for the owner of a building which is on fire that has the fire department waiting for POCO to disconnect power to the building because they can't get to the disconnect means. The building being on fire... not the owner :)
 
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mtaylor said:
If this is the case I feel sorry for the owner of a building which is on fire that has the fire department waiting for POCO to disconnect power to the building because they can't get to the disconnect means. The building being on fire... not the owner :)
Click to expand...

That same scenario could occur without using under-slab conductors. A disconnect is allowed inside, nearest the point of entrance of the service conductors. That could just as well be on the inside of an exterior wall that is some distance away from a building entrance.

The NEC regulations concerning main disconnect location are IMO attempting to limit the length of service conductors inside the building. They do not necessarily make it easier for the fire department to get to the disconnect. If the fire department is concerned about that, they will have to make some additional requirements to address the issue
 
The requirement for an outside disconnect has long been blamed on the fire service and used by many jurisdictions to justify the installation. Most people end up installing them because the first accessible point is the living room wall, and they don't want the disconnect there. Every jurisdiction has some magical formula on how far service conductors can enter a structure before a disconnect is required.
Fire departments typically do not want to pull a meter because of the hazards it exposes. The utility companys try hard to get a lineman there quickly, but sometimes we just can't wait. On our department there are a couple guys that are allowed to pull meters with a safety devise and immediately install a blank cover so no exposed energized parts can be touched. Too many meters have exploded on people that do not know what they are doing. I saw one guy trying to pull a bolt in meter and he got his butt chewed real bad.
 
Sorry for the bump, but I've run into a similiar situation.

While the inspector was out looking at a new service we installed (we divided a tenant space in two) he asked where the service disconnect was for the original space, which is located right inside the building from the pad mounted transformer.

The inspector wanted us to redo the existing service to add an exterior disconnect. I priced this up, and the owners of the building are baulking at the cost - and I would think rightfully so.

Can I just point to 230.70 (A) (1), or does the AHJ pretty much have the authority to make the changes? I believe he gave us 14 days from when he pointed it out to have the changes made, and I think the owners of the shopping center are planning to meet with the city today.

I hope that was clear enough, please let me know if more information is needed. The service in question is metered at the poco transformer.
 
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