How do I properly size a cord drop?

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electricus

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The circuit is 100A, 480VAC 3 phase, protected with a 100A breaker feeding #3 THHN, then to a junction box transitioning to a drop cord.

In the past (for smaller 30 amp drops) I've used table 310.15(B)(16) for the THHN and table 400.5(A) for the cord. Table 400.5(A) only goes up to #2 with column A highest rating of 80 amps.

What table do I use to figure the proper size cord for my 100 A requirements?
 
electricus said:
The circuit is 100A, 480VAC 3 phase, protected with a 100A breaker feeding #3 THHN, then to a junction box transitioning to a drop cord.

In the past (for smaller 30 amp drops) I've used table 310.15(B)(16) for the THHN and table 400.5(A) for the cord. Table 400.5(A) only goes up to #2 with column A highest rating of 80 amps.

What table do I use to figure the proper size cord for my 100 A requirements?
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Do they even make a flex cord a size higher than #2?? I see in the other table that has 400.5(B) that deals with cables where you can get your ampacity up higher.

What exactly are you feeding or powering with this flex cord??
 
[QUOTEDo they even make a flex cord a size higher than #2??][/QUOTE]
I don't know for sure, I'm going to see what is available. I thought I saw 1/0 installed once.

I see in the other table that has 400.5(B) that deals with cables where you can get your ampacity up higher.
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You are correct with the higher ampacity but this is for a SC, SCE, SCT, PPE, G, G-GC and W. I was originally looking at SO, but these other types look like they would be very similar, and serve the purpose.

[QUOTEWhat exactly are you feeding or powering with this flex cord??][/QUOTE]

Manufacturing ceiling vertical cord drop to a machine in part of a line that gets moves around slightly, they don't want hard pipe drop. Other thought was drop sealtite flexible conduit, but I don't know if that is common practice for an instance like this, will also have to check code compliance.
 
My guess is you have to use one of the cable types in 400.5(B).

I know I have seen larger than 2 AWG flexible cords/cables but was not involved enough that knowing what kind of cable it was. I have installed 200 amp pin and sleeve receptacles at small hospitals where a mobile MRI scanner in a truck trailer comes and plugs into the receptacle. All I was involved with was installing the 200 amp receptacle. I've seen them come with the truck and the driver just about needed another truck to drag the cord over to the receptacle to plug it in.
 
kwired said:
My guess is you have to use one of the cable types in 400.5(B).

I know I have seen larger than 2 AWG flexible cords/cables but was not involved enough that knowing what kind of cable it was. I have installed 200 amp pin and sleeve receptacles at small hospitals where a mobile MRI scanner in a truck trailer comes and plugs into the receptacle. All I was involved with was installing the 200 amp receptacle. I've seen them come with the truck and the driver just about needed another truck to drag the cord over to the receptacle to plug it in.
Click to expand...

I have some 1/0 cable that came from a welder that I made into jumper cables. Very flexible and very heavy. There is no markings, but the strands are fine and the insulation looks like plain old rubber. I wouldn't use it on anything but 12 volts, but it reminds me of diesel locomotive cable which is somewhat flexible and comes in large sizes.
 
i have seen 2ga 5 wire so cord , i know in SC cable they goto 4/0 you might check with a company that deals with temp power stuff
or the circus folk they use to pretty big cord
 
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