Conduit Fill Rules for TC Cable

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Saturn_Europa

Saturn_Europa

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Electrician Limited License NC, QMED Electrician
I am running a circuit to a HVAC condenser unit. Its a 26 FLA demand and a 300' run. The manual said maximum voltage drop is 2%. My plan was to run the wire in a cable tray, then transition to 1" ridged aluminum conduit for the outside of building. Due to the voltage drop I will have to run 6/2 with a ground TC cable. I will also have to run 12/2 with ground TC cable for my convenience outlet. Are there special rules for conduit fill when it comes to TC cable?
 
Saturn_Europa said:
I am running a circuit to a HVAC condenser unit. Its a 26 FLA demand and a 300' run. The manual said maximum voltage drop is 2%. My plan was to run the wire in a cable tray, then transition to 1" ridged aluminum conduit for the outside of building. Due to the voltage drop I will have to run 6/2 with a ground TC cable. I will also have to run 12/2 with ground TC cable for my convenience outlet. Are there special rules for conduit fill when it comes to TC cable?
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as far as I can tell if you can jam it in the tube it is probably OK.
 
Saturn_Europa said:
I am running a circuit to a HVAC condenser unit. Its a 26 FLA demand and a 300' run. The manual said maximum voltage drop is 2%. My plan was to run the wire in a cable tray, then transition to 1" ridged aluminum conduit for the outside of building. Due to the voltage drop I will have to run 6/2 with a ground TC cable. I will also have to run 12/2 with ground TC cable for my convenience outlet. Are there special rules for conduit fill when it comes to TC cable?
Click to expand...

Essentially, when you put multiconductor cables in a conduit, you treat them as if each cable were a perfect circle with a diameter equal to the largest possible diameter (if there is an ovalish shape to the cable). And then you apply the standard 53%/31%/40% rules. Or 60% if it is 2 ft and less.
 
Smart $ said:
Depends on the TC cable. Many TC power cables run all the same size conductors and no downsized EGC.
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I don't see a lot of larger TC but I can't recall ever seeing one with a smaller EGC in it, but maybe my memory is confused. I don't recall for sure but I also seem to recall the grounds are usually bare, but I might be remembering funny about that too.
 
petersonra said:
I don't see a lot of larger TC but I can't recall ever seeing one with a smaller EGC in it, but maybe my memory is confused. I don't recall for sure but I also seem to recall the grounds are usually bare, but I might be remembering funny about that too.
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I'm aware w/G is available, but I've never seen a Type TC power cable with a designated EGC.
 
We pulled in almost 9,000' of tray cable at a mill in washinton, each one had 3 (three) 500MCMs with a 250 gnd (insulated)! But it was aluminum, not as hard a job as it sounds:)
 
Now that we have told you how to build the clock, we might tell you the time :)
IN answer to your original question, see Note 9 in the Notes to Table 9 where you will find a multi-conductor cable is treated as a single conductor in determining conduit fill. Determine the area of your cable and check the Table a single conductor of the same area.
 
augie47 said:
Now that we have told you how to build the clock, we might tell you the time :)
IN answer to your original question, see Note 9 in the Notes to Table 9 where you will find a multi-conductor cable is treated as a single conductor in determining conduit fill. Determine the area of your cable and check the Table a single conductor of the same area.
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6/3 TC cable has an outside diameter of 0.69

In order to save space, I was going to change out the 12/3 with 14/2 and use the ground in the 6/3 for the outlet and HVAC system. I am pretty sure I can do this because both circuits will originate at the same panel.

14/2 TC cable has an outside diameter of 0.34

This puts the conduit fill at 51%. So it looks like I will have to upsize my conduit.

When I called the supply house, they didnt have 6/2 with ground only 6/3 in red, black, and blue. There is an exception for the EGC to be marked green when its part of a multiwire cable, installed in an industrial setting that is only accessible to qualified individuals.
 
Smart $ said:
I'm aware w/G is available, but I've never seen a Type TC power cable with a designated EGC.
Click to expand...

I agree that most of the ones I have seen that are smaller (< 10 awg) all the conductors typically are insulated. I was referring to larger ones, not that I have seen very many of them.

I don't know if the larger cables typically come with full size grounds or not. I think you can pretty much get whatever you want these days. Sometimes it is pretty cost effective to get only what you need.
 
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