Temporary breaking of electrical clearances in substation

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DanPaul

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Location
United States
There is a scenario where anticipated flooding in a substation (over 600 V and not accessible to unqualified personnel) would lead us to sandbag around equipment to protect it. This would effectively raise the ground level and could break electrical clearances. According to 110.27 this would need to be guarded to prevent accidental contact. The action that we would take is to put in guards around the area to keep workers from standing on top of the wall. According to the second approved action we would have to install "suitable permanent, substantial partitions or screens so that only qualified personnel have access to live parts."
Since the sandbags are temporary what would the definition of "suitable permanent" guards be? I would assume we could put some temporary fence around the area that can be removed when the sandbags are removed. I would think that permanent could mean as permanent as the sandbags are.
 

GoldDigger

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Placerville, CA, USA
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Retired PV System Designer
In applying 110.27 (4), I would say that the temporary sandbags do not constitute a floor, and if you take steps to prevent workers from standing on them they are not a working surface either.
IMHO under those conditions if you were in compliance with (4) before the sandbags, you do not have to look at using the other sections, (1)-(3), to maintain compliance.
 

greenspark1

Senior Member
Location
New England
Sounds like you are thinking ahead and taking proactive measures to ensure workers are guarded from accidental contact. I would not typically call the top of a sandbag a working surface. Now if you build it 4' wide and put drywall on top then maybe now you would consider it a work surface.
 

charlie b

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Lockport, IL
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Since the equiptment is very much not likely to "require" maintenance while energized under the temporary conditions you describe, the requirements for maintaining working clearance pretty much vanish.
 

GoldDigger

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Location
Placerville, CA, USA
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Retired PV System Designer
The section the OP cited has nothing to do with either working clearance or dedicated space. It has to do with safety clearance to live parts which will be exposed during normsl operation, not just during maintenance.
One example would be an overhead open bus conductor within a substation.

Tapatalk!
 

DanPaul

Member
Location
United States
The section the OP cited has nothing to do with either working clearance or dedicated space. It has to do with safety clearance to live parts which will be exposed during normsl operation, not just during maintenance.
One example would be an overhead open bus conductor within a substation.

I am interested in safety clearance to live parts. Any further guidance on the subject?
 
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