Pulling new circuit through existing conduit

[thewire]

I have a question on pulling new circuit through an existing conduit that already have multiple circuits in place. Assuming the conduit fill under XX%, is there a problem with either NEC code or rubbing on the existing cable and wearing the insulation out? The new cable will be fully lube.

 

[cadpoint]

If the new total will be under is under 40%, sure.

I would not use any metal finger grip or metal attachment, only staggered wires and
to say .1/4" or .3/8" rope. I'd also strongly consider stranded wire for the pull!

If age is a problem, Meggar the exisintg circuits and retest after pull.

 

[thewire]

If the new total will be under is under 40%, sure.

I would not use any metal finger grip or metal attachment, only staggered wires and
to say .1/4" or .3/8" rope. I'd also strongly consider stranded wire for the pull!

If age is a problem, Meggar the exisintg circuits and retest after pull.

Thanks. The existing conduit is actually duct. Walker Duct

 

[charlie b]

I think it would be safer (i.e., lower risk of damage to the existing wires) to pull them out, and pull the old and new together back through the raceway. Is that even an option?

 

[qcroanoke]

I think it would be safer (i.e., lower risk of damage to the existing wires) to pull them out, and pull the old and new together back through the raceway. Is that even an option?

Many times if I needed two wires I would use one existing wire as a pull wire to pull three wires in. two wires that I needed for the new circuit and one to replace the one I pulled out.

 

[arion]

ditto on Qc's suggestion of using the existing line to pull in 3.

 

[ActionDave]

Pulling new wires in an existing conduit is standard stuff, especially walker duct. I would use an existing wire like Qc said also.

 

[infinity]

We do it all of the time. Usually pull out an EGC and pull in new conductors with a replacement EGC. If friction might be an issue just add some lube to the new condcutors.

 

[kwired]

If you pull all conductors out and reinstall with added conductors have you really reduced any "dragging" of existing against either

A: the new conductors

B: the interior of the raceway

?

Either way something is going to drag on something else.