Clamping NM-B entering into PVC Enclosure

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Logisticsman

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In a previous thread I had explained how I am going to be running electrical power from my residence to a detached garage that is currently under construction. Forum Users have provided excellent answers to my previous questions regarding this project and I thank them all.

I have a question concerning the clamping of a 6/3 NM-B cable that will originate from my residence's service panel, be fed through the residence's exterior brick surface, and then enter into the back of a 6x6x4 surface mounted NEMA 4 PVC enclosure. In reading NEC's Chapter 314.17 (C), it states that any nonmetallic sheathed cable entering a nonmetallic box must be clamped inside the enclosure. There is an Exception to this requirement, but it only applies if the enclosure dimensions are not larger than a nominal size of 2.25" x 4". This limitation in size means the Exception can not be applied in my project's case.

Given the information in the above paragraph, I am a bit uncertain as to the best method to clamp the incoming 6/3 NM-B cable within the PVC enclosure. I am thinking of using a cable connector inserted into the entry hole I will be creating in the enclosure. Would this satisfy the cable clamp requirement? The cable connector I am considering using would be the type as shown in the attached photo. Thank you.
 

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What is your relation to the electrical industry? This seems like a DIY post, which is not allowed. PM me if I have misjudged this.
 
The OP is formerly a journeylevel electrician and works in the electrical industry. For us mods the user occupation is not filled out, so we often don't know.
 
Logisticsman said:
in reading NEC's Chapter 314.17 (C), it states that any nonmetallic sheathed cable entering a nonmetallic box must be clamped inside the enclosure. There is an Exception to this requirement, but it only applies if the enclosure dimensions are not larger than a nominal size of 2.25" x 4". This limitation in size means the Exception can not be applied in my project's case.
Click to expand...

Don't know where you got that, it's "Where nonmetallic-sheathed cable or multiconductor Type UF cable is used, the sheath shall extend not less than 6 mm (1⁄4 in.) inside the box and beyond any cable clamp. In all instances, all permitted wiring methods shall be secured to the boxes".

The Exception refers to the normal plastic device and receptacle boxes where you just shove the NM through the KOs and staple it within 6".

I think your non-metallic connector is fine if it accommodates the thickness of the PVC box side. But if it were me with 6/3 I would opt for a two screw metallic connector just because it's more secure. I'll let others debate as to whether it would require bonding in this instance. But that could easily be done with a grounding bushing.

-Hal
 
hbiss said:
Don't know where you got that, it's "Where nonmetallic-sheathed cable or multiconductor Type UF cable is used, the sheath shall extend not less than 6 mm (1⁄4 in.) inside the box and beyond any cable clamp. In all instances, all permitted wiring methods shall be secured to the boxes".

The Exception refers to the normal plastic device and receptacle boxes where you just shove the NM through the KOs and staple it within 6".

I think your non-metallic connector is fine if it accommodates the thickness of the PVC box side. But if it were me with 6/3 I would opt for a two screw metallic connector just because it's more secure. I'll let others debate as to whether it would require bonding in this instance. But that could easily be done with a grounding bushing.

-Hal
Click to expand...
Hello hbiss,

Thank you for your reply to my question. I guess I did not properly state my understanding of the NEC regarding the"...all permitted wire shall be secured to the boxes" text. I should not have described it as being "clamped inside the enclosure". Thank you for clarifying how it is properly stated/meant.
 
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