Help needed 13,800 Volts

[kisselect]

I was asked to look at a job where the incoming Voltage is 13,800 Volts to a residential High Rise

They want to install the following

High voltage Service room in Basement. 1 transformer step down 13,800 to 600 volts Switch gear 600 volts
Second run 13,800 Volts from High Voltage Service Room to Roof Area 1 Transformer step down 13,800 to 600 volts. Switch gear 600 Volts


Has anyone seen this type of an installation ?
Is High Voltage at 13, 800 volts NOT INCASED IN CONCRETTE OK
Are there any interference issues with High Voltage, communications, lighting, etc.
Any input is welcome.


Thanks

 

[augie47]

Fairly common on high-rise jobs. 13.8 to top for elevator & HVAC power.
Not something you would want to tackle without training.
300.37 will give you some ideas on wiring methods.
Their "600 volt" I would think would be gear rating with actual voltages of 480 or 208/120.

 

[kisselect]

Fairly common on high-rise jobs. 13.8 to top for elevator & HVAC power.
Not something you would want to tackle without training.
300.37 will give you some ideas on wiring methods.
Their "600 volt" I would think would be gear rating with actual voltages of 480 or 208/120.

Thanks for your reply
Would the high voltage 13.8 have any interference with lighting, data, etc
The concept behind running 13.8 up to the roof is to save on pipe and wire instead of running 600 feeds
This way they feed down part of the building from the roof

 

[iwire]

Thanks for your reply
Would the high voltage 13.8 have any interference with lighting, data, etc

Only if you run those other systems in the same conduit.

The concept behind running 13.8 up to the roof is to save on pipe and wire instead of running 600 feeds
This way they feed down part of the building from the roof

We understand the reasons and as Gus said this is very common in tall buildings.

 

[iwire]

You may have to sub out the 13.8 pulling and terminations if your people are not already trained for that work.

We would run the pipe, help with the pulling and let a trained subcontractor do the terminations.

 

[Jraef]

Thanks for your reply
Would the high voltage 13.8 have any interference with lighting, data, etc
The concept behind running 13.8 up to the roof is to save on pipe and wire instead of running 600 feeds
This way they feed down part of the building from the roof

Shouldn't be a problem. You might be thinking this in terms of HV distribution lines, but they are not shielded. When you run them, you will have to use shielded cable and if properly installed, they should not cause interference.

Your having to ask however makes me wonder, as augie47 implied, if you might be biting off more than you can chew here. MV primary work is not for the uninitiated even if you have years of success with LV work. It's something you learn at the feet of an experienced pro over years before taking it on solo.

 

[Cow]

I never knew they used such high voltages in high rises! I assumed it was all done with huge 480v bussduct running bottom to top with taps made at each floor? The good thing though is it might only take a #2 at that voltage to feed half the building!:lol:

Similarly, we did a large digester project with three 1600kw 4160v cat generators. They bumped the generator output up to 34.5kv through a step up transformer where it tied into the overhead lines. It's amazing all this power runs through a single set of 1/0's on the high side.

 

[augie47]

Shouldn't be a problem. You might be thinking this in terms of HV distribution lines, but they are not shielded. When you run them, you will have to use shielded cable and if properly installed, they should not cause interference.

Your having to ask however makes me wonder, as augie47 implied, if you might be biting off more than you can chew here. MV primary work is not for the uninitiated even if you have years of success with LV work. It's something you learn at the feet of an experienced pro over years before taking it on solo.

and IT (13.8) IS VERY UNFORGIVING !!!

 

[Jraef]

and IT (13.8) IS VERY UNFORGIVING !!!

I tell newbies that with low voltage, you kind of have to work at getting to where you can touch it and get hurt.
With Medium Voltage, you just have to be close enough for it to jump out and find you!

 

[Sahib]

Is High Voltage at 13, 800 volts NOT INCASED IN CONCRETTE OK

Not OK because the MV cable is from POCO's feeding point and may not have proper O/C protection.

 

[kisselect]

Not OK because the MV cable is from POCO's feeding point and may not have proper O/C protection.

Just like to thank all for your input.
Yes 13.8 is not for everybody, including me to work on.
That's why I had the questions.
The 13.8 will be done by a H.V. Contractor

 

[Smart $]

...
Is High Voltage at 13, 800 volts NOT INCASED IN CONCRETTE OK
...

Not OK because the MV cable is from POCO's feeding point and may not have proper O/C protection.

Depends on whether the run is service or feeder conductors.

If service conductors and installed within the building envelope, they will have to to be installed under the conditions stated in 230.6(2) or (3).

Feeder conductors are required to have proper OCP and have no requirement for additional physical protection.

 

[iwire]

​

Depends on whether the run is service or feeder conductors.

If service conductors and installed within the building envelope, they will have to to be installed under the conditions stated in 230.6(2) or (3).

Yes and I have been on a job where that was the case.

A 13.8 KV service was run up inside a three story building to the roof where three 4000 amp services where installed.

Nondescript brick building with no names on it but its own substation and a fleet of locomotive size generators outside.

Pretty sure our tax dollars built it.

 

[Sahib]

Depends on whether the run is service or feeder conductors.

Feeder conductors are required to have proper OCP and have no requirement for additional physical protection.

Feeder conductors? Good for POCO also then because the energy losses in the feeder conductors also measured by the energy meter installed by POCO at the ground floor. Wonder Why they don't make installation of energy meter at ground floor mandatory in multistorey buildings.

 

[Open Neutral]

Yes and I have been on a job where that was the case.

A 13.8 KV service was run up inside a three story building to the roof where three 4000 amp services where installed.

Nondescript brick building with no names on it but its own substation and a fleet of locomotive size generators outside.

Pretty sure our tax dollars built it.

Let me guess: large HVAC units, well out of proportion to human occupancy.
Limited entrances with vestibules.
BTDTGTTS

 

[Smart $]

... Wonder Why they don't make installation of energy meter at ground floor mandatory in multistorey buildings.

Perhaps they do, even for rooftop services. I don't know as I have never been involved with such an installation... but it is not that hard to do.

Nowadays, they even include data transmitters in the meters. Meter readers don't even have to stop and get out of their vehicle. That's how my home meter is read.

 

[GoldDigger]

Perhaps they do, even for rooftop services. I don't know as I have never been involved with such an installation... but it is not that hard to do.

Nowadays, they even include data transmitters in the meters. Meter readers don't even have to stop and get out of their vehicle. That's how my home meter is read.

Beyond even that, current "smart meters" use their wireless data communications capability to form themselves into a mesh network where each meter is capable of relaying the data of other smart meters until the data reaches a wireless collection point in the utility network and makes the transition to another communications channel all the way back to the central office where it is noted by the computers.
Not even a drive by is necessary except perhaps in low density/rural areas.

And, as has been noted in other threads, with that also comes the great power to remotely turn off a contactor contained in the meter and disconnect your power. Not good enough for a safety disconnect, but perfectly good for billing enforcement. AFAIK they have not gone the extra mile to install a large contactor for CT based meter installations.

 

[Sahib]

One important goal of data collection from smart meters at least for one utility is to predict any black out and to take preventive action in time.

 

[iwire]

Let me guess: large HVAC units, well out of proportion to human occupancy.
Limited entrances with vestibules.

Exactly.

You would be lucky to find the entrance.

 

[GoldDigger]

Exactly.

You would be lucky to find the entrance.

I remember that time in the 60's when the most likely windowless unlabeled large building would be the Telco central exchange.
We did have the famous Blue Cube (Onizoka Air Force Base) next to Moffet Field. The big satellite dishes all around gave you a good idea what was going on inside that one.

And then there was the Bank of America office campus in the Peninsula foothills where none of the buildings were numbered or labelled so you could not find the computer center. Unfortunately all of the plastic tape blocking off the parking spaces closest to it was another dead giveaway.