Service Disconnect Means

[dasan384]

Hello guys, I need an advise for a problem I have with a 4 story building. The Main Electrical Room is located at the second floor of the building. There is no space in ground floor, so the only option I have is that one. I have a 1200 Amp main disconnect switch on the main electrical room,so my problem is with the location of the main service disconnect, I know that it has to be in a readily accessible location as per [230.70(A)(1)], So I was planing to use a Shunt Trip and a push button close to the main entrance. I am confused because a recent addition to Section 230.70 is permission to use shunt trip devices at the service disconnecting means located within the building but locating the shunt trip remote operating devices on the outside of the building or close top main entrance, so this permits the fire department or other emergency response teams to disconnect power to the building without having to enter the building first. My problem is that these remote devices are not listed for use as service disconnecting means, as required by 230.66, so the service disconnecting means must still be in a readily accessible location [230.70(A)(3)]. As before, this will be outside the structure, or if inside nearest the point of entry of the service conductors. Thanks in advance for any suggestion.

 

[iwire]

The company I work for often puts electrical rooms deep inside buildings or on upper levels and rarely do we provide anything more than the disconnecting means at that location.

When local areas request a shunt trip button we locate it wherever they ask. Often this ends up beside the fire alarm control panel other times in the main entry area. If in a public area we use a 'Stopper' http://www.sti-usa.com/series/universal-stopper/ over it.

On another topic how are you dealing with the service conductors in the building? (This has to do with 'nearest the point of entrance' and how it affects the requirements in 230.70)

 

[augie47]

Sounds as if 230.70 would be your major obstacle. You might take a look at 230.6 for a possible solution

 

[dasan384]

The company I work for often puts electrical rooms deep inside buildings or on upper levels and rarely do we provide anything more than the disconnecting means at that location.

When local areas request a shunt trip button we locate it wherever they ask. Often this ends up beside the fire alarm control panel other times in the main entry area. If in a public area we use a 'Stopper' http://www.sti-usa.com/series/universal-stopper/ over it.

On another topic how are you dealing with the service conductors in the building? (This has to do with 'nearest the point of entrance' and how it affects the requirements in 230.70)

Thanks for the quick response. The utility transformer is located on the parking lot, so my service conductors are coming underground pass the main lobby and goes up to the main electrical room which is located on top on the main lobby. I don't know if this helps with the question you asked.

 

[iwire]

The utility transformer is located on the parking lot, so my service conductors are coming underground pass the main lobby and goes up to the main electrical room which is located on top on the main lobby.

Yes this is what I was getting at.

The shunt trip does not change the need for an overcurrent device nearest the point of entrance of the service conductors. From you description that would be before the lobby.

The way around this is to follow the rules in the section Gus mentioned 230.6 For instance you can encase the conduits in masonry and they are not considered inside the building until the encasement stops.

230.6 Conductors Considered Outside the Building.
Conductors shall be considered outside of a building or
other structure under any of the following conditions:

(1) Where installed under not less than 50 mm (2 in.) of
concrete beneath a building or other structure

(2) Where installed within a building or other structure in a
raceway that is encased in concrete or brick not less
than 50 mm (2 in.) thick

(3) Where installed in any vault that meets the construction
requirements of Article 450, Part III

(4) Where installed in conduit and under not less than
450 mm (18 in.) of earth beneath a building or other
structure

(5) Where installed in overhead service masts on the outside
surface of the building traveling through the eave
of that building to meet the requirements of 230.24

 

[dasan384]

Yes this is what I was getting at.

The shunt trip does not change the need for an overcurrent device nearest the point of entrance of the service conductors. From you description that would be before the lobby.

The way around this is to follow the rules in the section Gus mentioned 230.6 For instance you can encase the conduits in masonry and they are not considered inside the building until the encasement stops.

Thank you very much, my concern was exactly about that.