Switchroom Construction

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tepres

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I can't find any references for switchroom construction, NEC, building, or otherwise. I recommended a block room. However, when the price came back, the proj manager requested a metal studded drywall room. I don't think I have an arguement here unless I can find something in our internal standards. Just looking for some affirmation.

Indoor unit substation:
15kV interrupter
13.8kV pri 480V sec Dry type xfmr 2000KVA
GE AKRU Low Voltage Sw gear

Thanks,
Tim
 
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elohr46

Senior Member
Location
square one
tepres said:
I can't find any references for switchroom construction, NEC, building, or otherwise. I recommended a block room. However, when the price came back, the proj manager requested a metal studded drywall room. I don't think I have an arguement here unless I can find something in our internal standards. Just looking for some affirmation.

Indoor unit substation:
15kV interrupter
13.8kV pri 480V sec Dry type xfmr 2000KVA
GE AKRU Low Voltage Sw gear

Thanks,
Tim
Click to expand...

Have you read 110.30(A) & (B)
 
weressl

weressl

Esteemed Member
Location
Texas by the Gulf, geat crab, great shrimp
tepres said:
I can't find any references for switchroom construction, NEC, building, or otherwise. I recommended a block room. However, when the price came back, the proj manager requested a metal studded drywall room. I don't think I have an arguement here unless I can find something in our internal standards. Just looking for some affirmation.

Indoor unit substation:
15kV interrupter
13.8kV pri 480V sec Dry type xfmr 2000KVA
GE AKRU Low Voltage Sw gear

Thanks,
Tim
Click to expand...

Just from the arc flash containment standpoint, I would want to see a concrete block construction at all times. Not that it will necessarily contain the blast but minimize external damage.
 
H

hurk27

Senior Member
Location
Portage, Indiana NEC: 2008
Not sure if it sate requirement or not, but around here it gets an impenetrable block room if there are any open live HV parts, enclosed type transformers with no expose live HV parts no problem.
 
Pierre C Belarge

Pierre C Belarge

Senior Member
Location
Westchester County, New York
Tepres
I believe that 110.31 would apply to your installation.
The building code in your jurisdiction may require different applications, and you should contact them to make sure. I am not sure if an engineer/architect is involved, this would normally be their responsibility.


The last sentence of 110.31(A):
"For the purpose of this section, studs and wallboards shall not be considered acceptable."

If anything, I would show them this, to support your side of the discussion.
 
T

tepres

Member
Pierre C Belarge said:
The last sentence of 110.31(A):
"For the purpose of this section, studs and wallboards shall not be considered acceptable."

If anything, I would show them this, to support your side of the discussion.
Click to expand...

Yeah, that's kinda where I'm leaning. I'll be calling the AHJ.

Any way we can get that vaults better defined (or defined at all) in the next cycle? Anyone out there on the right panels?
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Pierre C Belarge said:
If this question is directed towards my post, I am curious, as the utility company usually follow much more stringent requirements than we do in our part of the industry.
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It was directed at the OP.

I would grant you that a block room would provide better blast resistance, but double sheet rock walls are pretty solid.

I had not really considered whether the utility company had any requirements for the room construction, or considered the special requirements for switchgear rooms over 600V. The code seems pretty clear that sheet rock walls are not acceptable over 600V.
 
Last edited:
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Transformer vaults are described in Art 450 III.
In my opinion, the install you describe does not require a vault per 450.21.
Vaults are not discussed except over 35,000 volts (450.24) or oil-Insulated (450.26).
 
Pierre C Belarge

Pierre C Belarge

Senior Member
Location
Westchester County, New York
tepres said:
ok,
I'm going to make them go with block.
It's still driving my crazy though. Can anyone define a vault?
Click to expand...



The portion of a bank where they keep our money...:D



In numerous locations in the NEC, the term vault is used. It invariably refers back to Article 450, Part III. In 110.31, including subsection (A). There is also information about vaults.

I do not believe you will find a definition of vault per se. In my opinion you are best off referring to 110.31 and Part III of Article 450.

I took a quick look through the ICC and did not find and info there either.
 
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