Folks - I'm bringing in a new medium voltage underground service into a basement switchgear with metering. The service point is out on a pole, and the conductors for the service lateral are customer owned. I understand what 230.6 states in order to know how those conductors are to be considered outside a building, but where in the Code does it state that the service conductors need to be outside the building?:-?
230.6 - Services considered outside the building
- Thread starter thorpe16
- Start date
- Status
- Location
- Logan, Utah
Check out 230.70(A)(1).
The service conductors must terminate in the serivce disconnecting means which in accordance with 230.70(A)(1) must be located outside the building or inside nearest the point of entrance of the service conductors.
Chris
The service conductors must terminate in the serivce disconnecting means which in accordance with 230.70(A)(1) must be located outside the building or inside nearest the point of entrance of the service conductors.
Chris
Since "service" is defined as conductors from the serving utility, the service condcutors are automatically outside (unless your building is the utility).
In your case, IMO, your service point is where your customer owned cables connect to the utility owned cables and you are now under the rules of Art 225.
In your case, IMO, your service point is where your customer owned cables connect to the utility owned cables and you are now under the rules of Art 225.
Thanks augie47. But I thought about that, too. And if you look in the Handbook at the picture in 230.31, where the service point is out on the pole, our service disconnect is in the switchgear in the basement. (And of course there's the fused disconnects out on top of the pole for the utility). So I'm not sure if they're feeders yet...
- Location
- Logan, Utah
The lenght of conductors allowed within the building is really up to the AHJ. I know some allow 15' and some don't allow anything.
Chris
- Location
- Illinois
- Occupation
- retired electrician
Even with the service point out on the pole, these conductors are still service conductors until after the service disconnect. The 2011 code would call these conductors "service conductors, underground" or "service conductors, overhead" as the case may be. These are the conductors between the service point and the "service enterance conductors". The terms "service drop" and "service lateral" are now for the conductors on the line side of the service point. The "service conductors, underground" are covered by the rules in Article 230, not Article 225.
- Location
- Logan, Utah
Gus, the service point is defined as " The point of connection between the facilities of the serving utility and the premises wiring."
In the OP the underground service conductors are customer supplied but are still part of teh service conductors until they terminate in the service disconnecting means.
Chris
I agree... my mind went down the wrong road.... happens
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Washington State has imposed a 15 foot limit. I don't know whether New Jersey has a similar rule. In order to comply with this rule, I have had to encase a medium voltage service in 2 inches of concrete as it passed just inside an outer wall on its way to the electric room on the second floor. What was interesting is that the concrete only had to go up about 10 feet above the first floor's floor level, because beyond that point the conductors were within 15 feet of the service equipment. 
cadpoint
Senior Member
- Location
- Durham, NC
- Occupation
- Electrician - but not by NC Law.
Did everyone miss this?
Would you please define the exact size of the voltage or even kV?
I believe you should schedule a meeting with the AHJ, the POCO, the owner and yourself so that all will agree to be on the same page.
I think your be surprised at the results!
ANSI/IEEE 1585-2002 refers to: Medium Voltage
IEEE Std 1623-2004 refers to: Devices rated to medium voltage
To clarify, it is a 12 kV service from the local utility. The project is being built now and falls under the guidelines of the 2008 Code. The service disconnecting means, as I understand it, is inside the building in the switchgear lineup within a few feet of the exterior wall. So, until those conductors hit the first disconnect, they are customer owned service conductors as in 230.200 (see Exhibit 230.31, but our transformer is indoors, and this is similar to other installations in this jurisdiction). So, to go back to my original question, do these customer owned 12 kV service conductors need to be installed in concrete encased conduits inside the building, or can the be exposed RMC conduits?
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I think this has been answered. The code will considered it outside the building when encased in concrete. RMC is not enough, however the code states it must terminate as near as possible to the where the cables enter the building. Some areas req. a disco before it enters while other areas have exact distances in their amendment.
Thanks everyone! I actually did get ahold of the local L&I inspector and he suggested keeping it encased in 2" concrete to keep it out of the building - becasuse even though it is "supervised", one doesn't know what will end up in the space between the gear and the wall, be it flamable or not... Or, he suggested going directly to a fused disconnect right inside the wall. Then the conductors would be protected and safe just in conduit.
Thanks again!
Thanks again!
- Location
- Illinois
- Occupation
- retired electrician
I don't think that really makes that much difference. The arc blast and flash hazard is often much greater on the lower voltage system than on the medium voltage system.
- Location
- Logan, Utah
I agree,
I have been reviewing an arc flash study for a local meat packing plant and the arc flash hazard catagory for the medium voltage switchgear (12.7Kv) is a 2* but the hazard catagory for some of the 480 volt switchgear down stream is above hazard catagory 4.
Chris
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