paulgarett
Member
- Location
- San Rafael, CA
Is their a code requirement for pull boxes for a certain distance of a conduit run?
Pull Boxes
- Thread starter paulgarett
- Start date
- Status
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
paulgarett said:
No code requirement for distance without a pullbox. Max. 360 degrees of bends
jrannis
Senior Member
- Location
- Fort Lauderdale/ Miami
paulgarett said:
Ok this is where I thought it was 500' but soon forund out I was wrong.
Then we started talking about how much pull the wire could stand.
Then it seemed that 500' was about max. Not due to the conduit run, only due to the limits of the cable or wire.
brian john
Senior Member
- Location
- Kilmarnock, Va
- Occupation
- Retired after 52 years in the trade.
Just my opinion but they can always be bigger. I see so many pulls that are made more difficult than they need to be by using the minimum size box. IMO bigger is better.
- Location
- Illinois
- Occupation
- retired electrician
You need to do a pulling calculation for long runs and shorter runs with larger cable. Most of the time the pulling tension is not the limiting factor. The sidewall pressure is. The sidewall pressure (crushing force on the insulation as the conductor is pulled around a bend) may require the use of pull points or large radius bends.
charlie
Senior Member
- Location
- Indianapolis
paulgarett said:
The following is one of the FPNs to Table 1 in Chapter 9:
FPN No. 1: Table 1 is based on common conditions of proper cabling and alignment of conductors where the length of the pull and the number of bends are within reasonable limits. It should be recognized that, for certain conditions, a larger size conduit or a lesser conduit fill should be considered.
Of course a FPN is not enforceable but it does contain valuable information. The insulation can be damaged if the length of the run is too long.
You might want to read FPN No. 2 as well. :smile:
- Location
- Massachusetts
charlie said:
It is interesting to note that the couple of pulling tension calculators I have seen ignore conduit size, they assume NEC compliant fill.
You can also get into jamming calculations but that is really a separate issue then pulling tension and sidewall pressure. Sometimes a larger conduit increases the chances of jamming.
Pulling
- Status