440.22(c)

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chris kennedy

Senior Member
Location
Miami Fla.
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60 yr old tool twisting electrician
I have a situation where the EE speced a 200A safety switch fused at 110A for CU-1. The equipment arrives and it turns out CU-1 is actually two units that work in tandem. MOCP for each unit is 40A. While composing a RFI I sited 440.22(C). Although this is in chapter III of 440, upon reading 22(C) the highlighted areas below threw me:



Where maximum protective device ratings shown on a manufacturer?s overload relay table for use with a motor controller are less than the rating or setting selected in accordance with 440.22(A) and (B), the protective device rating shall not exceed the manufacturer?s values marked on the equipment.

Did I site the correct article?

Thanks
 

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
I'm seeing 'overcurrent' and 'overload' .

Here is the title of the section.


III. Branch-Circuit Short-Circuit and Ground-Fault Protection

Here is the article.

440.22(C) Protective Device Rating Not to Exceed the Manufacturer?s Values.
Where maximum protective device ratings shown on a manufacturer?s overload relay table for use with a motor controller are less than the rating or setting selected in accordance with 440.22(A) and (B), the protective device rating shall not exceed the manufacturer?s values marked on the equipment.

I'm confused by the first part of this sentence, why the talk of the overload relay chart?
 

mcclary's electrical

Senior Member
Location
VA
Here is the title of the section.




Here is the article.



I'm confused by the first part of this sentence, why the talk of the overload relay chart?



To me, it means if the manufacturer has already gone through the trouble of listing the overload relays to be used with theire motor controller, then you cannot go above that number.
 

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
To me, it means if the manufacturer has already gone through the trouble of listing the overload relays to be used with theire motor controller, then you cannot go above that number.

I'm not sizing overload relays, I'm sizing the fusible safety switch supplying the branch circuit conductors to the units.:-?
 

Smart $

Esteemed Member
Location
Ohio
I'm not sizing overload relays, I'm sizing the fusible safety switch supplying the branch circuit conductors to the units.:-?
I agree that subsection is confusing. Every time I run into that one I mentally substitute "nameplate" for "overload relay table".
 
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