Can someone help me with finding a definition to "...effectively guarded by insulating materials." 110.34(A) Condition 1

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careful

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I'm struggling to find a black and white definition, or even a solid example to NEC's Condition 1 for 1000+V working space. Does anyone have a good example of how this would be accomplished in the real world? Does the material need to carry a certain dielectric of resistive rating?
Thanks

Note: Where the conditions are as follows:
Condition 1 — Exposed live parts on one side of the working space and no live or grounded parts on the other side of the working space, or exposed live parts on both sides of the working space that are effectively guarded by insulating materials.
 
I think this may help

Definitions
Guarded.
Covered, shielded, fenced, enclosed, or otherwise protected by means of suitable covers, casings, barriers, rails, screens, mats, or platforms to remove the likelihood of approach or contact by persons or objects to a point of danger.
 
Dennis Alwon said:
I think this may help

Definitions
Guarded.
Covered, shielded, fenced, enclosed, or otherwise protected by means of suitable covers, casings, barriers, rails, screens, mats, or platforms to remove the likelihood of approach or contact by persons or objects to a point of danger.
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Thank you that does help with some examples. Do you know of any specific materials that could be used in construction ? I know there is a rating system for electric matting which is the closest I’ve gotten so far. I wish it were as simple as fire stopping and ratings.
 
careful said:
know there is a rating system for electric matting which is the closest I’ve gotten so far.
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This would be all I would accept for >1000V. I don't think anyone makes 'glastic' type sheets for walls and I have never heard of sprayon voltage rated insulation.
 
jim dungar said:
This would be all I would accept for >1000V. I don't think anyone makes 'glastic' type sheets for walls and I have never heard of sprayon voltage rated insulation.
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I’m having trouble finding permanent construction solutions that would meet this. Temporary or PPE type solutions are more common. I wish I could ask the guy that wrote that piece of code what they had envisioned.
 
careful said:
I’m having trouble finding permanent construction solutions that would meet this. Temporary or PPE type solutions are more common. I wish I could ask the guy that wrote that piece of code what they had envisioned.
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What is wrong with using the temporary methods like a mat?
 
don_resqcapt19 said:
Build or cover the wall with drywall. Drywall in not considered a grounded surface.
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My research on it gives mixed results. It’s definitely not a conductor, but it doesn’t appear to be a great insulator either. You probably need to stack them depending on how high your voltage is, but this is why I’d love for NEC to provide some examples. I also get mixed results on plywood.

Maybe we’re supposed to calculate the resistance needed at 4’ to prevent arcing.
 
careful said:
I’d love for NEC to provide some examples. I also get mixed results on plywood.
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The NEC is primarily 'what to do' not 'do it this way'. For example, it tells you how often conduit needs to be supported and fastened but leaves the actual methodology to the trained installer.
 
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Another option would be to call the head engineer in the state. In NC that is the man who heads the electrical division for the state and can make decisions on what is expected
 
In my experience the only reasonable way to meet it would be to use rubber blankets based on the voltage or impulse level of MV. Typically the rubber goods need to be tested regularly for abrasions, holes or failures to avoid any issues.

I would imagine, if your voltage is lower, like less than 10kV then you could probably get away with some type if thick plastic shielding? But you would need to pull some IEEE paper or get ahold of a MV switchgear manufacturer to figure out that stuff.
 
Elect117 said:
In my experience the only reasonable way to meet it would be to use rubber blankets based on the voltage or impulse level of MV. Typically the rubber goods need to be tested regularly for abrasions, holes or failures to avoid any issues.

I would imagine, if your voltage is lower, like less than 10kV then you could probably get away with some type if thick plastic shielding? But you would need to pull some IEEE paper or get ahold of a MV switchgear manufacturer to figure out that stuff.
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I don't see any thing that says the opposite wall has to be insulated for the voltage present. It just says "no live or grounded parts".

It would be nice to know what voltage we are talking about ,but I still say FRP. After all, the floor is still allowed to be bare concrete.
 
steve66 said:
I don't see any thing that says the opposite wall has to be insulated for the voltage present. It just says "no live or grounded parts".

It would be nice to know what voltage we are talking about ,but I still say FRP. After all, the floor is still allowed to be bare concrete.
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The title is asking about effectively guarded by insulating materials. The last part of condition 1. I was assuming they were talking about exposed live parts on both sides.
 
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