Common Usage of LFMC, LFNC 1

[EvanH]

NEC Articles 350.10 and 356.10 both use the language "Where conditions...require flexibility or protection of liquids..."

In common practice, is this interpreted as only device which need to move or vibrate are allowed to be connected with flexible conduit, instead of rigid or thin-walled conduit?

Or is it allowed more liberally, that saving labor and difficulty is a good enough justification to use flexible conduit to connect devices?

Thanks for any insight,

Evan

 

[REDDOG]

NEC Articles 350.10 and 356.10 both use the language "Where conditions...require flexibility or protection of liquids..."

In common practice, is this interpreted as only device which need to move or vibrate are allowed to be connected with flexible conduit, instead of rigid or thin-walled conduit? Yes

Or is it allowed more liberally, that saving labor and difficulty is a good enough justification to use flexible conduit to connect devices? No!

See Article 90 .1,.5,.6, Article 110 .1,.2,.3,.8,.11,.12

 

[EvanH]

Is there any difference in this answer for industrial machinery applications, as opposed to facility wiring, does anyone know? I've seen lots of devices connected with sealtite, like switches, solenoid valves, etc. that don't physically move, so I'm just wondering what the typical justification is.

Thanks again,
-Evan

 

[REDDOG]

Is there any difference in this answer for industrial machinery applications, as opposed to facility wiring, does anyone know? No
The problem is if the local AHJ inspection at installation
that wiring method may not be in compliance with the code.
The AHJ my give you some relief if the wiring method is not a flagrant violation. By this I mean if rigid raceway could not have be used is place of this non approved method.
I've seen lots of devices connected with sealtite, like switches, solenoid valves, etc. that don't physically move, so I'm just wondering what the typical justification is.

These items can be adjusted such limit switches, valve coils
can be removed from their base for service.

 

[dbaird]

NFPA 79 is used for Industrial Machinery and it permits the use of liquidtight flexible conduit and/or multiconductor cable (see section 16.3 Machine wiring).


David Baird
mrbaird@hotmail.com

Sr Controls Engineer

EET degree.

Journeyman Electrician.