Flexible metallic conduit above false ceiling

TMMB

Senior Member
I have an issue regarding the flexible metallic conduit as follows:

1-What is the maximum permitted length of the flexible metallic conduit FMC above false ceiling as per NEC?
2- There is coaxial cable for GSM system, can we use the FMC as main raceway for long length above false ceiling or there is limited length can not exceed it ?


Please advise
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
In general for FMC there is no length limit if 1/2" or larger and properly supported.
 

TMMB

Senior Member
but as per NEC 348.3 A as follows:

Exception No. 3]:Lengths not exceeding 1.8 m (6 ft) from a
luminaire terminal connection for tap connections to luminaires
as permitted in 410.117(C).

Exception No. 4": Lengths not exceeding 1.8 m (6 ft) from
the last point where the raceway is securely fastened for
connections within an accessible ceiling to luminaire(s) or
other equipment

it is limited to 1.8 m , or no limited length?
 

roger

Moderator
Staff member
Location
Fl
Occupation
Electrician
The exceptions are pertaining to 3/8" FMC.

Roger
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Electrician
but as per NEC 348.3 A as follows:

Exception No. 3]:Lengths not exceeding 1.8 m (6 ft) from a
luminaire terminal connection for tap connections to luminaires
as permitted in 410.117(C).

Exception No. 4": Lengths not exceeding 1.8 m (6 ft) from
the last point where the raceway is securely fastened for
connections within an accessible ceiling to luminaire(s) or
other equipment

it is limited to 1.8 m , or no limited length?
That should be 348.30

The exceptions are pertaining to 3/8" FMC.

Roger
No, the exceptions are for securing and supporting.

It is saying that the maximum length that can be unsupported if flexibility is needed is the lengths that are listed in the exceptions according to the FMC size.

But to the OP's question, there is no length limit if properly supported/secured.
 

roger

Moderator
Staff member
Location
Fl
Occupation
Electrician
That should be 348.30



No, the exceptions are for securing and supporting.

It is saying that the maximum length that can be unsupported if flexibility is needed is the lengths that are listed in the exceptions according to the FMC size.

But to the OP's question, there is no length limit if properly supported/secured.
I guess I should have looked, I was replying from memory and thinking of the exceptions to 348.20(A)


Roger
 
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