Liquid tight and carflex bonding jumper

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dburney

Member
Location
Brooklet ga usa
I have an underground feed comeing from an mdp gear in pvc then transitions to rmc comeing out the ground then changes to a short section of carflex and in some spots sealtight before entering a mini power zone. My question is do they need to install a bond jumper around the section of flex and if so can you let me know where in the code book to find it thanks
 

kwired

Electron manager
Location
NE Nebraska
I have an underground feed comeing from an mdp gear in pvc then transitions to rmc comeing out the ground then changes to a short section of carflex and in some spots sealtight before entering a mini power zone. My question is do they need to install a bond jumper around the section of flex and if so can you let me know where in the code book to find it thanks

Flex needing bonding around depends on size and overcurrent protection level.

But you also need to somehow bond all the isolated metallic sections as well. My understanding is there is multiple isolated metallic raceway sections in the run. Were we using up all the scraps we could find here?:)
 

Carultch

Senior Member
Location
Massachusetts
I have an underground feed comeing from an mdp gear in pvc then transitions to rmc comeing out the ground then changes to a short section of carflex and in some spots sealtight before entering a mini power zone. My question is do they need to install a bond jumper around the section of flex and if so can you let me know where in the code book to find it thanks

Unless it is an isolated section that is completely buried the requisite 18 inches below grade, all metallic conduits need to be electrically continuous with the equipment grounding system.

An application of this, is if you are using an RMC sweep in the middle of a PVC run, and you are opting to use RMC sweeps because you anticipate the sidewall pressure of the wire pull. The RMC sweeps & stubs at the beginning and end of the run would bond to your enclosures, but the isolated underground sweep would not. Provided that it is entirely buried the required 18" below grade, it is OK that it isn't.

In your question, you have LFMC isolated between PVC connecting to each piece of equipment. What you'd need to do, is use a bonding LFMC connector connected to one of the PVC female adapters, and then route an external bonding jumper from one of the enclosures to it. The bonding capabilities of LFMC only apply, when you've got a metal LFMC connector terminating on each enclosure in an electrically continuous manner.

Any particular reason you are using a short section of LFMC instead of LFNC? If you use LFNC, you wouldn't need to bond it.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I have an underground feed comeing from an mdp gear in pvc then transitions to rmc comeing out the ground then changes to a short section of carflex and in some spots sealtight before entering a mini power zone. My question is do they need to install a bond jumper around the section of flex and if so can you let me know where in the code book to find it thanks

When using the trade names Carflex and Sealtight do you mean LFNC and LFMC? For LFMC being used as an EGC look at 250.118(6)a-e.
 
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