wireman3736
Senior Member
- Location
- Vermont/Mass.
I have always understood that electrical and plumbing threads were different, I have read alot of conflicting imfo on this and even mentioned this at my code update course and was told they were straight even though I referenced 344.28, all the guys in the class agreed with him and said you could not use plumbing dies. I always new the couplings were straight but felt there was a taper in the pipes we threaded, I don't do much threading and just went with the flow since I wasn't buying them and only used them. Now that I work for myself I have been thinking about buying a ratcheting hand threader and a couple of dies for explosion proof I do once in awhile and service masts that I do quite a bit. Today I got my code question of the day that I get and more confusion. this is what it said.
Answer to Previous Code Question of the Day for Friday, June 23, 2006
Question:
Greetings:
I teach the first and secnd year curricula at the Denver Joint
Electrical Apprenticeship Training Program, and some of my students
have followed my suggestion to become subscribers to your Code Question
of the Day.
We would like to know definitively whether or not differences exist
between the appropriate thread pitches for threaded conduit and
threaded plumbing pipes. For instance, we know that the National
Electrical Code requires 3/4-inch taper per foot for rigid conduit.
We are told that threaded plumbing pipe also requires a 3/4-inch
taper per foot. That would certainly indicate that the same dies could
be used for all same-size piping needs on any given job, unless there
are differences in the pitch. Is it appropriate and correct to thread
both with the same set of dies??
THANKS!!
ED Knox
Aurora, CO 80013
Answer:
Hi Ed, thanks for putting your guys onto CQD. NECA 101-2001,
Standard for Installing Steel Conduits, Section 4.1.1 says "Although
coupling threads are straight-tapped, conduit threads are tapered. Use
a standard 3/4-inch per foot taper National Pipe Thread (NPT) die."
This is, indeed, the same die that plumbers use.
Section:
NECA-NEIS 101-2001
Source:
Charlie Trout
Can anyone convince me to what is right.
Thanks Stan![Confused :confused: :confused:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Answer to Previous Code Question of the Day for Friday, June 23, 2006
Question:
Greetings:
I teach the first and secnd year curricula at the Denver Joint
Electrical Apprenticeship Training Program, and some of my students
have followed my suggestion to become subscribers to your Code Question
of the Day.
We would like to know definitively whether or not differences exist
between the appropriate thread pitches for threaded conduit and
threaded plumbing pipes. For instance, we know that the National
Electrical Code requires 3/4-inch taper per foot for rigid conduit.
We are told that threaded plumbing pipe also requires a 3/4-inch
taper per foot. That would certainly indicate that the same dies could
be used for all same-size piping needs on any given job, unless there
are differences in the pitch. Is it appropriate and correct to thread
both with the same set of dies??
THANKS!!
ED Knox
Aurora, CO 80013
Answer:
Hi Ed, thanks for putting your guys onto CQD. NECA 101-2001,
Standard for Installing Steel Conduits, Section 4.1.1 says "Although
coupling threads are straight-tapped, conduit threads are tapered. Use
a standard 3/4-inch per foot taper National Pipe Thread (NPT) die."
This is, indeed, the same die that plumbers use.
Section:
NECA-NEIS 101-2001
Source:
Charlie Trout
Can anyone convince me to what is right.
Thanks Stan