I know that specifications will often not allow the use of running thread. On the job I am now on this is not the case, the specs say nothing. My question is, 'Does the code allow running thread to be used as a chase between panels that are more than 12" apart?' If possible please reference the 1999 code as that is what we are using in our area. Thanks for your help!
Improper use of running thread
- Thread starter jchrist
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- Illinois
- Occupation
- retired electrician
Re: Improper use of running thread
The only code rule that I know of says that you can't use running thread at couplings (342.42 and 344.420). It is often used between panels.
The code sections are 345.9 and 346.9 in the '99 code.
Don
[ October 01, 2003, 12:00 PM: Message edited by: don_resqcapt19 ]
The only code rule that I know of says that you can't use running thread at couplings (342.42 and 344.420). It is often used between panels.
The code sections are 345.9 and 346.9 in the '99 code.
Don
[ October 01, 2003, 12:00 PM: Message edited by: don_resqcapt19 ]
Re: Improper use of running thread
Many confuse running threads with all thread. A running thread is a straight thread (no taper).
A thread cut longer than the standard length is a running thread, the lack of a taper will prevent it from being wrench tight. Butting ends of pipe in a coupling is not an approved connection.
Generally, a connection with 2 or more visible threads is a running thread.
An example of standard thread length;
1/2 inch total make up 17/32", 7 1/2 turns.
1/2 inch, 14 threads per inch, turns for hand tight 4 1/2, Turns for wrench make up 3.
Anything more is a running thread.
Many confuse running threads with all thread. A running thread is a straight thread (no taper).
A thread cut longer than the standard length is a running thread, the lack of a taper will prevent it from being wrench tight. Butting ends of pipe in a coupling is not an approved connection.
Generally, a connection with 2 or more visible threads is a running thread.
An example of standard thread length;
1/2 inch total make up 17/32", 7 1/2 turns.
1/2 inch, 14 threads per inch, turns for hand tight 4 1/2, Turns for wrench make up 3.
Anything more is a running thread.
- Location
- Illinois
- Occupation
- retired electrician
Re: Improper use of running thread
Bennie,
How is "all thread" different? It is also straight thread and is what you get if you run the conduit die down the length of the pipe.
Bennie,
How is "all thread" different? It is also straight thread and is what you get if you run the conduit die down the length of the pipe.
Re: Improper use of running thread
Thanks for the reply Bennie. One of the difficult things about being an engineer is understanding the terms and slang electricians use. I spent a year as a apprentice, but still only learned a fraction of the slang terms.
Steve
Thanks for the reply Bennie. One of the difficult things about being an engineer is understanding the terms and slang electricians use. I spent a year as a apprentice, but still only learned a fraction of the slang terms.
Steve
Re: Improper use of running thread
Threaded fitting make up in electrical conduit is exactly the same as a pipe fitter connecting water lines.
Many do not believe this, but it is required for proper equipment grounding purposes. When the metal to metal fit is tight enough for pressure, it will also be a low impedance electrical connection.
Threaded fitting make up in electrical conduit is exactly the same as a pipe fitter connecting water lines.
Many do not believe this, but it is required for proper equipment grounding purposes. When the metal to metal fit is tight enough for pressure, it will also be a low impedance electrical connection.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Improper use of running thread
I belive that lamp nipples are allowed as running thread but it is mostly just for support and not for bonding.
I belive that lamp nipples are allowed as running thread but it is mostly just for support and not for bonding.
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