I recently failed an electrical inspection on a main panel upgrade because I used a 2 inch twin screw clamp connector to bring in several lengths of romex. I was always taught that this was ok until I failed this last inspection. I was looking through the nec and found 312.5(C) and it seems that all romex needs to enter the panel individually. Does anyone have any further information. I have never had a problem using the one larger connector and really would like to be able to argue this with the inspector. Any help would be much appreciated. Thanks
NMC connector
- Thread starter aherman
- Start date
- Status
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
It should be okay, IMO but the 2" NM connector is probably only listed for one maybe 2 cables. 110.3(B)
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
According to the UL White Book, TYZX, cable fittings are designed for one cable per cable entry unless marked otherwise on the box.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Whether it was over-filled, under-filled or perfectly-filled you've violated the listing of the connector. There is no way of knowing that the 2" connector when tightened will properly secure that cables as required by the UL standard used to test connectors.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
And there you have it. One of the main purposes of the cable clamp is to secure the sheath so it won't slide outside of the enclosure.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I think that we've all done things because we were taught that way even if those ways were incorrect. For example, I cannot count how many times I've been told that you need a pull point for every 100' of conduit. :roll:
- Location
- Massachusetts
Doesn't your areas amendment mention a 3" long raceway?
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
As I mentioned before, unless the carton you buy the connector in specifies otherwise, all SE connectors are listed for only one cable. If you didn't see any indication otherwise on the box, it is clear the connector was intended for one cable, if it was listed.
The one specifically from Phoenix was really poorly written. The other 15 or so municipalities have their own versions of this although I have only read Chandler and Gilbert's version.
For some reason it said not less than 3"' long which would not apply to all of the standard methods used (snap in, chase nipple and PVC TA).
Why did they write it that way? Because whoever wrote it doesn't work in the field?
The 3" length will sometimes take it too far into the wall cavity. In new construction with foam/stucco exterior, the 3" is about right but even a TA isn't quite that long.
If they would have just asked me, I'd set them straight.
For one- and two-family dwellings, cables with entirely non metallic sheaths
shall be permitted to enter the back of a surface-mounted enclosure through one or more
nonflexible raceways not more than 75 mm (3 in.) in diameter, and not less than 75 mm
(3 in.) and not more than 600 mm (24 in.) in length
renosteinke
Senior Member
- Location
- NE Arkansas
Look at the box the connectors come in. You will find that they are listed for as many as TWO flat cables or one round one.
The UL marking guides / white book reinforce this point; if the item is too small to mark with this information, the information will be on the smallest packaging.
The UL marking guides / white book reinforce this point; if the item is too small to mark with this information, the information will be on the smallest packaging.
jimthesparks
Member
- Location
- Chicago, IL
I've learned that is more because of fish tapes then anything else.
- Status