is hard pipe required for temporary heating fan

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malachi constant

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Minneapolis
We have a situation where a high school gymnasium's RTU is being replaced. We are in a northern climate, and it's quickly turning into winter, so a few weeks ago the team installed a temporary heater (ducted to an exterior gas-fired element) and temporary fan, which will remain in place until the RTU is replaced. I am told it should be complete by end of next week. The gym remains occupied for PE and after-school volleyball/basketball activities. The temporary equipment is currently installed via cord - I'm not familiar with it but sounds like it is connected via an NM or SO cord-and-plug to a 208V outlet installed for temporary power.

Today the inspector requested that the cord be removed and that the temporary equipment be fed via hard pipe (EMT). (For one week.) The construction team is asking us (design engineers) if this is a code requirement. Here's what I found:

NEC Article 590 governs Temporary Installations.
* 590.3 states we can't exceed 90 days, and we will not exceed that.
* 590.4(C) branch circuits allows multiconductor cords or cables. Type NM, NME and SE shall be permitted to be used in any dwelling, building or structure without any height limitation or limitation by building construction type and without concealment within walls, floor or ceilings.
* 590.4(H) requires protection from accidental damage. This seems to be mainly concerned with sharp corners and passing through doorways. I am not too concerned with volleyballs.

So I'm not a big expert on temporary power, but in reviewing 590 I think although the code allows for some areas of discretion/interpretation, our installation meets the letter and intent of the code. Maybe the cord needs swapped out with NM or SE if it is not already one of those. Obviously, at the end of the day the inspector is going to get what he wants, but this information at least gives the construction team some talking points to engage with the inspector. Any thoughts?

Thanks!
 
It sounds like the area in question is occupied; normally it would be up to the authority if temp wiring methods could be approved in an occupied area.
 
david said:
It sounds like the area in question is occupied; normally it would be up to the authority if temp wiring methods could be approved in an occupied area.
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I had skimmed over 590.2(B) - "temporary wiring methods shall be acceptable ONLY IF approved based on conditions of use and any special requirements of the temporary installation." I presume that what you are referring to? I agree, that pretty much puts it at his discretion.
 
From where I sit, the inspector is being totally unreasonable if is done in a safe manner in compliance with 590. I would take this above him if it was my jobsite.
 
Today the inspector requested that the cord be removed and that the temporary equipment be fed via hard pipe (EMT). (For one week.) The construction team is asking us (design engineers) if this is a code requirement. Here's what I found:
Click to expand...

Just wondering why was the inspector on site, did someone call for an inspection?
 
Where is this temporary circuit being run? Indoors, outdoors? If indoors is it behind rated construction finish?

Gymnasium likely is a place of assembly, but if behind floor, wall, ceiling finish might not need to comply with 518.

If outdoors can't be NM cable.

In any case probably still need to consider protection from physical abuse, but the temporary nature of this can use temporary protection where needed also.

I also agree that by time all red tape gets cleared up it may not even be in use anymore.
 
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