Physical Cable Protection Requirement

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I have a wall mounted 350A receptacle being connected via a wall mounted 350A fused disconnect (400A). The receptacle, already approved by the end user, can only take in 185mm2 cable at max. The contractor is trying to use 185mm2 cable that has a capacity of over 350A in air but only 306A once in conduit. So his proposal is to protect the cable between the disconnect and the receptacle using a custom fabricated metal mesh between the and use the air rating of the cable.
I don't think it is code compliant and if I could use the 24" nipple rule to have the cable in conduit.
Any suggestion to fix the issue is highly appreciated.
 

Smart $

Esteemed Member
Location
Ohio
First of all, let's talk NEC-recognized wire and cable types. Absolutely none use metric sizing... so your first problem is whether or not the cable being used is actually Code compliant.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I have a wall mounted 350A receptacle being connected via a wall mounted 350A fused disconnect (400A). The receptacle, already approved by the end user, can only take in 185mm2 cable at max. The contractor is trying to use 185mm2 cable that has a capacity of over 350A in air but only 306A once in conduit. So his proposal is to protect the cable between the disconnect and the receptacle using a custom fabricated metal mesh between the and use the air rating of the cable.
I don't think it is code compliant and if I could use the 24" nipple rule to have the cable in conduit.
Any suggestion to fix the issue is highly appreciated.

185 mm^2 is roughly 350 KCM. Likely only good for 310 A in the NEC, assuming it is even a NEC recognized cable. Put a 300A CB on the wire and it is code complaint, assuming the wire is acceptable to the code.

How is it that the end user "approved" a receptacle that may not be code compliant?

I am not convinced that a metal mesh is free air. I am also not convinced that it even needs protection.

I think you will find that the specs being touted for this cable are something the manufacturer made up and not NEC values.
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
North of the 65 parallel
Occupation
EE (Field - as little design as possible)
I am of the third kind iceworm...the lowly designer
Yes that was my guess. Mostly pointing out to Tony that wasn't part of the answer. Hower, to his defense, knowing which dog you had in the race who would help with tailoring the response. No disrespect intended to either.

ice
 
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