Romex clamp and Bell box

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don_resqcapt19 said:
But UL says connectors have not been evaluated for use with anything other than lock nuts, so it doesn't matter is it is a hub or a threaded entry that you want to use the connector with. Note that saying they have not been evaluated for a use is not the same as saying they can't be used for that use.
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In many of the threaded entries that are not an integral hub, one can still get a lock nut on the connector because the threads are only the thickness of the box wall. Some entries have an internal boss to make it thicker, so using a locknut may not be an alternative.

Is the evaluated only with locknut with respect to grounding or attachment? For non-metallic conduits and cables, grounding isn't an issue.

I agree that not evaluated does not mean cannot be used in another capacity.
 
I have never had an issue threading a rx connector, emt, rigid or pvc into a threaded bell box. Are the threads really different? I have never noticed it.
 
In any case I see no issue with a rx connector in the back of a box coming from a dry location. I don't believe that needs to be weather resistant but if the box is held off the wall I would probably put a little duct seal on it. I also see no issue with the threads
 
Smart $ said:
In many of the threaded entries that are not an integral hub, one can still get a lock nut on the connector because the threads are only the thickness of the box wall. Some entries have an internal boss to make it thicker, so using a locknut may not be an alternative.

....
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The few bell boxes that I have used, you would not be able to get a lock nut on the inside.
 
John120/240 said:
Agree with all of the above opinions. Not a violation. In lieu of a romex connector I have used a Arlington 1/2" black button.
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Never tried one of those with a threaded hub in a bell box...not sure that would work well, but haven't tried it.

---Aaron
 
Dennis Alwon said:
In any case I see no issue with a rx connector in the back of a box coming from a dry location. I don't believe that needs to be weather resistant but if the box is held off the wall I would probably put a little duct seal on it. I also see no issue with the threads
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Ok, now that we have settled the romex connector question, what about raintight fittings such as an EMT compression connector into the side bottom or top of a bell box, or an LB or other conduit body? The raintight connectors usually have a locknut and a gasket...but obviously the locknut cannot be used with a bell box.

For the sake of argument, assume a separate EGC is being pulled so there isn't an issue with that.

This is something I have done many times, and seen done all over the place.
 
John120/240 said:
Maybe (probably not) the Arlington button is not listed for the application, but I haven't lost any sleep.
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I will neither confirm nor deny the number of times I haven't even used a romex clamp into the back of a bell box for an exterior receptacle. Put a staple close enough to the box it holds the wire nice and tight and you don't need to drill an 1 1/8" hole in the sheathing that way to fit the clamp in the hole to make everything nice and flush.

Clamps aren't even required for single gang plastic boxes as we know, but God forbid if we don't use one going into the back of a bell box.

I will never understand where some of the code comes from.

I like the idea of the push in connector with a bell box. Going to have to try that.
 
abrace said:
Ok, now that we have settled the romex connector question, what about raintight fittings such as an EMT compression connector into the side bottom or top of a bell box, or an LB or other conduit body? The raintight connectors usually have a locknut and a gasket...but obviously the locknut cannot be used with a bell box.

For the sake of argument, assume a separate EGC is being pulled so there isn't an issue with that.

This is something I have done many times, and seen done all over the place.
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Unless you have RMC or IMC it's not compliant. Here's an older but relevant article from Mark Ode, a highly respected engineer from UL, which explains the problem with straight threads and hubs.

http://www.ecmag.com/section/codes-standards/fittings-hubs

For even more explanation here's a great article from IAEI:

http://iaeimagazine.org/magazine/2012/07/16/transitioning-between-raceways/
 
infinity said:
Unless you have RMC or IMC it's not compliant. Here's an older but relevant article from Mark Ode, a highly respected engineer from UL, which explains the problem with straight threads and hubs.

http://www.ecmag.com/section/codes-standards/fittings-hubs

For even more explanation here's a great article from IAEI:

http://iaeimagazine.org/magazine/2012/07/16/transitioning-between-raceways/
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In my opinion Mark has overstepped here. UL has not evaluated the connectors for use with female threads. That is not the same as UL saying you can't do it. This is an area that, since the issue is not exactly covered by the listing standards, that it falls to the AHJ to approve.

Every electrician that works in industrial facilities installs connectors in female threaded fittings almost every day. I would expect that the percentage of LFMC connectors used with their lock nuts in industrial applications is less than 5%. The rest are threaded into conduit couplings, conduit bodies or threaded ports on equipment. There have been no known issues with that practice and it is very unlike to ever change.

In fact it is probably an area where the code could specifically permit it with a PI and a substantiation that says "we have been doing this for years without any problems". Other industrial rules have been put into the code with that substantiation.
 
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abrace said:
I will neither confirm nor deny the number of times I haven't even used a romex clamp into the back of a bell box for an exterior receptacle. Put a staple close enough to the box it holds the wire nice and tight and you don't need to drill an 1 1/8" hole in the sheathing that way to fit the clamp in the hole to make everything nice and flush.

Clamps aren't even required for single gang plastic boxes as we know, but God forbid if we don't use one going into the back of a bell box....
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I will confirm I have done it. Not a lot but more than once.
 
don_resqcapt19 said:
In my opinion Mark has overstepped here. UL has not evaluated the connectors for use with female threads. That is not the same as UL saying you can't do it. This is an area that, since the issue is not exactly covered by the listing standards, that it falls to the AHJ to approve.
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I agree, as I've said in the past 95% of all residential services in this area are either SE cable or PVC, all of which have a connector threaded into a meter hub. That means that every one of them is a violation.

IMO the listing should reflect the common usage of the products when it's been done in that way for 75 years, so either the testing standard should change or the products should be made different to comply with the current standard. The problem is when you print articles like the ones I linked to previously you get inspectors rejecting perfectly safe installations because someone wrote an article in a well respected magazine.
 
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