Are standard conduit bodies illegal now?

Hltracey

Member
Location
Ferndale MI
Per the 2011 NEC section 314.28 (A)(1) and (2)

"Where splices or where angle or U pulls are made, the distance between each raceway entry into the box or conduit body and the opposite wall of the box or conduit body shall not be less than six times the trade size of the largest raceway".

Same goes for straight pulls except it is 8 times the diameter of the largest raceway.

This means for example that a 3" C would have to have at least 24" between raceways, and an LB would have to have at least 18" between raceways.

Sounds like the standard condulets can't be used any more and everything will have to be mogul. I recently saw this enforced on a job, AFTER the conductors were in place!!
 

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
This requirement hasn't changed from earlier Code cycles.

Note that it only applies to raceways containing conductors of 4 AWG or larger
 

augie47

Moderator
Staff member
Location
Tennessee
Also take a look at 314.28(A)(3) which allows you to use a conduit body with a less than 6X dimension, however, in most case you will find the lsiting and marking will still not allow the maximum the conduit will allow. There are conduit bodies that will allow the same fill as the conduit such as Crouse-Hinds "NEC" series.

This chart may help:

View attachment industrial-fittings-wire-fill-chart.pdf
 
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don_resqcapt19

Moderator
Staff member
Location
Illinois
Also take a look at 314.28(A)(3) which allows you to use a conduit body with a less than 6X dimension, however, in most case you will find the lsiting and marking will still not allow the maximum the conduit will allow. There are conduit bodies that will allow the same fill as the conduit such as Crouse-Hinds "NEC" series.

This chart may help:

View attachment 9228
The chart brings up a problem. The code rule says that the maximum size and number of conductors must be marked on the conduit body itself. The only markings I have ever seen on a conduit body is for 3 conductors of "X" size. There is no code provision that permits the use of the conduit body fill in the manufacturer's table or to do a field calculation for wires sizes that are not marked on the conduit body.
314.28(C) ...provided the box or conduit body has been listed for, and is permanently marked with, the maximum number and maximum size of conductors permitted.
 

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
The chart brings up a problem. The code rule says that the maximum size and number of conductors must be marked on the conduit body itself. The only markings I have ever seen on a conduit body is for 3 conductors of "X" size. There is no code provision that permits the use of the conduit body fill in the manufacturer's table or to do a field calculation for wires sizes that are not marked on the conduit body.
Look at 314.16(C)
 

augie47

Moderator
Staff member
Location
Tennessee
The chart brings up a problem. The code rule says that the maximum size and number of conductors must be marked on the conduit body itself. The only markings I have ever seen on a conduit body is for 3 conductors of "X" size. There is no code provision that permits the use of the conduit body fill in the manufacturer's table or to do a field calculation for wires sizes that are not marked on the conduit body.
I have not compared the chart to many conduit body markings, but off-hand I don't know that there is a problem. The chart seems to agree with the markings as to the maximum number of a specific size wire allowed. It simply expands the info to include smaller sizes.
For instance, the chart shows a maximum of (3) 500s in a 3" LBD880 which I think is the same as marked on the body but the chart also notes (4) 400s
 

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
i believe in earlier code cycles the words "conduit bodies" we're not there, only requirements for junction boxes
They have added the words "conduit bodies" into 314.28(A)(1) and (2), but read 314.28. It says
Boxes and conduit bodies used as pull or junction boxes shall comply with 314.28(A) through (D)
In the earlier codes, conduit bodies were still required to comply with 314.28(A).
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
The rule in 314.28(C) needs to be changed to permit the combinations that are listed on the manufacturer's documentation and not restrict you to the combination that is marked on the conduit body itself. I have never seen a conduit body that was marked for more than 3 conductors. Many circuits require more than 3 conductors so you have us a conduit body that has 8x conduit spacing for straight runs and 6x spacing for 90? runs.
 
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