Need to pull new conductors through a conduit

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Old 06-30-13, 10:50 AM
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Need to pull new conductors through a conduit

I have to add 3 new conductors to a 75' long conduit run.

1/2" EMT conduit, all #12 conductors. All existing conductors are solid. The three new ones I am adding is stranded #12.

I also want to delete an existing solid conductor (wrong color).

There are six conductors in there now. I understand the max is 9 for #12 in a 1/2" conduit. So this would be very tight. Since I am taking one out, I will end up with 8 in there.

Is it better to remove the extra wire first, then use fish tape to pull the three new conductors? Or is it better to use the existing extra conductor as a fish tape to pull the three new ones?

If I use a fish tape, with the existing wires in that conduit, should I pull one at a time, or all three in one shot?
 
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Old 06-30-13, 11:02 AM
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I don't have my fill chart with me now but I think you will be overusing the conduit. You need to allow for derating with more than 4-6 current carrying conductors in a conduit.

I can give you some generic help.

You can use one ground wire in the conduit.....you don't need multiple ground wires.

You could try to attach your new wires to the one that needs to be pulled out but the main problem is that when multiple wires are installed in a pipe they twist which means you'd be pulling the new wires thru the old ones that are twisted. You'll need some pulling gel.

If you pull one at a time.....the head is too large and will bind in the conduit.

It's almost better pulling all the wires at one time.
 
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Old 06-30-13, 12:27 PM
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1/2 inch EMT will allow for 8 type T (plus adders) insulated conductors. If using type THHN you derate from the 90 degree C. column and that allows up to 9 conductors and still a full 20 amperes.

Pulling additional conductors will be difficult. Best to pull all of them out first and then pull the new package through in one pull.
 
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Old 06-30-13, 06:18 PM
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Based on the chart I consulted for 1/2" EMT with #12 I can have up to 9 conductors.

But I was mistaken, I looked again and it's a 3/4" EMT, not 1/2".

If I pull them all out and repull them in one shot, how would I attach it to the fish tape loop? Wouldn't the "bundle" there be actually too thick or do I need to stagger them?
 

Last edited by MiamiCuse; 06-30-13 at 07:09 PM.
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Old 06-30-13, 06:24 PM
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Since your new wires are the longest.... you strip those two or three and put them thru the snake loop. Now....slightly stagger the existing wires and tape them to the new wires.

Keep the taped part short or when you get the bundle out of the end of the pipe you won't be able to get the tape off.
 
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