ECN Forum Forums General Topics of the Trade General Discussion Area NEC- 314.23 (H) (1)

Does a SO cord drop need a threaded hub or can you use a blank cover or knock out from a 4 square or octagon box? Also is it allowed just to have a cord cap on end of SO cord or do you need a approved pendant box? I don't think using a 4 square box with k.o.'s is allowed for pendant boxes either.

Thanks for any help.

The first question is answered in the title you posted.


I suppose the second question is in the listing of the cord cap. (receptacle)
I know it is common to see pendants terminated with Russell Stoll or IEC 309 receptacles.

So you could use a T-11 Box or similar?

How long has a threaded hub been required?

The first place I see that language is a code change to the 1987 370.13(h).

Thanks for reply. As I understand it a T-11 is not allowed either..an FD box would be...osha has a section on this.

I ended up using a rigid T with a dead leg on one side for support and a 4 square on the other to make connections.

You see a lot of cord drops with 4 square boxes or cord cap on the end of so cord but these are actually a code violation.

I suppose using a T-11 (Bell box) would be a local call since it is a threaded entry but that probably actually gets back to the listing and a 110.3(b). I bet they say that box needs to be attached to something.

I believe there are cord grips for some of the pin and sleeve receptacles that are listed for pendant use but that is not the same as a garden variety 5-15 receptacle cap you see on a field assembled/repaired extension cord.

I seem to recall the “threaded hub pendant” first appearing around 2005. I still haven’t dug out my code library

The change came about after a prominent inspector made it a priority — even a holy cause — after his successful campaign to ban drywall screws. In the course of traveling to conduct seminars, he found many DIY extension cords with four-square boxes that had suffered from abuse. Hence the code change.

At that time I posted a picture here of a simple cord cap hanging from a pendant. I believe the conversation here was lively but inconclusive — with objections centering on whether the court cap was suitable for outdoor locations.

As far as strain relief is concerned, even UL is stumped. They have two wildly different standards and even they’re not sure when to apply each. Even 2-screw NM/FMC connectors are listed (look at the box) for gripping flexible cords in some applications. Other situations seem to require both Chinese handcuffs and compression clamps.

Threaded hub for flexible cords was in the 1987 in article 370. In 2002 that got moved to a new article 314.23(h) and they added "pendant" to the language.

Thank you. Well, my mind hasn’t completely lost I 😁