Limit to FMC run length?

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cppoly

Senior Member
Location
New York
Is there a limit to vertical run length of FMC? I don't see any limit in Article 348. Vertical support should be every 6'?
 
Smart $

Smart $

Esteemed Member
Location
Ohio
cppoly said:
Is there a limit to vertical run length of FMC? I don't see any limit in Article 348. Vertical support should be every 6'?
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No limit to run length of FMC specifically, but supporting conductors in vertical raceways enters the picture at some point, depending on size of conductors [300.19].

You'd be required to secure the FMC at intervals not exceeding 4-1/2 feet.
 
kwired

kwired

Electron manager
Location
NE Nebraska
Smart $ said:
No limit to run length of FMC specifically, but supporting conductors in vertical raceways enters the picture at some point, depending on size of conductors [300.19].

You'd be required to secure the FMC at intervals not exceeding 4-1/2 feet.
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Fished FMC can be unsupported, or maybe better choice of words would be no additional support is needed, cause if unsupported gravity has a tendency to keep it from remaining vertical.

Now what if we fished it vertically for 100+ feet:cool:
 
Smart $

Smart $

Esteemed Member
Location
Ohio
kwired said:
Fished FMC can be unsupported, or maybe better choice of words would be no additional support is needed, cause if unsupported gravity has a tendency to keep it from remaining vertical.

Now what if we fished it vertically for 100+ feet:cool:
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FWIW, 2011 NEC changed impractical in the exception to impracticable...
 
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cppoly

Senior Member
Location
New York
It's being used in an application where the FMC is used in long vertical run lengths (as a riser).

As a general rule, there are no length limits to any of the wiring methods in Chapter 3, correct? Because this is not a safety issue.
 
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
cppoly said:
It's being used in an application where the FMC is used in long vertical run lengths (as a riser).

As a general rule, there are no length limits to any of the wiring methods in Chapter 3, correct? Because this is not a safety issue.
Click to expand...

I believe that is correct that there is no length limit for runs.
 
kwired

kwired

Electron manager
Location
NE Nebraska
cppoly said:
It's being used in an application where the FMC is used in long vertical run lengths (as a riser).

As a general rule, there are no length limits to any of the wiring methods in Chapter 3, correct? Because this is not a safety issue.
Click to expand...

That is correct. Keep in mind FMC is a bear to pull through if it is not pulled tight and straight as possible.
 
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