ECN Forum Forums General Topics of the Trade General Discussion Area #3's in 1"

I may be helping another EC install new panels in some condos. Need to run the feeders to each unit for a 100a panel. The runs will be 100-180'. No good strait shots and probibly a number of obstructions. We may need to install some pull boxes because of all the bends.

I would like to use 1 1/4 EMT with 3 #2 or #3's (depending on length) because it will be reasonable to pull by hand. The other EC is thinking 1" EMT with 3 #3's because it is quicker to bend and would save maybe $1500 in material.

The inspecter already said 3 #3's is fine in 1" and is not worried about VD because of little load in each unit.

I never tried to pull 3 #3 in a 1" very far by hand but I wounder if it is possable with out a tugger.

Tom

Code wise...3 #3 thhn's in a 1" EMT do fit, but just barely ~
1/2" = 1 #3
3/4" = 1 #3
1" = 3 #3
1 1/4" = 6 #3
...that 1/4" makes a HUGE difference!


I recall a job I did where 11 #10 XHHW conductors were pulled in a 3/4" RGC for stub-ups(code allows 11 @ 3/4")...the rope broke once, the guys were POed at me all day...and it took 4 guys just to pull ~ not including the guys at the feed end. After this fiasco(which took about a 1/2 day to go just over 100'), I had the crew start running "extra" 3/4" conduits overhead.
The amount of effort that was required to get the wires in was not worth it.


For you, a small tugger(gets attached to a RA drill or hole hawg) might be a viable alternative...pay for it once, use it over and over again.

I've been down that road exactly one time and I learned my lesson. You might try the 1" for some of the shorter runs, but I'd strongly advise going to the 1 1/4 " EMT for anything with more than two 90 degree bends. If you opt for the 1", let us know how it went.

Tom

It's physically possible to pull four 3ga. wires in 1" IMC. With some lube you shouldn't have any problem. Additional pull points to keep it to two bends per pull will help. I recently PUSHED three 3 ga. in 1" IMC in short runs with one bend.

Dave

1" IMC is NOT the same as 1" EMT...1" IMC is allowed 4 #3's, 1" EMT is allowed 3 #3's.

Pushing 3 #3s in a 1" IMC is no special feat.

Right Celtic, I missed that one.

Dave

I don't know what area you are in but I'll tell you in the NorthEast, more and more MC and believe it or not SER is being used in the residential hi-rises. (Condo's Apartments, Dormitories
Engineers, inspectors and even the contractors are pushing it.

Have you thought of derating the neautral? Two number threes and a four or six.

Thanks for the replys.

Local thing min size 3 #3 for 100a residential.

After a bit I think we would be better off doing a larger pipe with a few sets of feeders. I'm thinking about a 2" with 9 #2's until it gets near the unit.

Tom

Funny.... Local PoCo here requires 1 1/4 min. for resi. (2" U/G) And Rare to find #3 stocked anywhere, almost like it doesn't exist. #4 - #2!