Motor Wire Sizing Question

[kenaslan]

I have an 800HP motor fed with 3 sets of 350KCMIL Teck-90 Cable.
The cable is rated at 325A.
3 Sets = 975A Derated for temp is 877.5A
The motor FLC is 714.5A PF is 80% so 714.5*1.25 = 893.13A
100% Cable spacing on Cable tray so no derating required.

Do I need to increase the cable size to 400KCMIL or is this okay?

Thanks
Ken

 

[weressl]

I have an 800HP motor fed with 3 sets of 350KCMIL Teck-90 Cable.
The cable is rated at 325A.
3 Sets = 975A Derated for temp is 877.5A
The motor FLC is 714.5A PF is 80% so 714.5*1.25 = 893.13A
100% Cable spacing on Cable tray so no derating required.

Do I need to increase the cable size to 400KCMIL or is this okay?

Thanks
Ken

Cable ratings per NEC are 260/310/350 per 310.16. Where do you get your cable rating from?

 

[kenaslan]

General Cable

This is not building wire but Teck-90 industrial cable for mining operations installed on a cable tray.

 

[weressl]

General Cable

This is not building wire but Teck-90 industrial cable for mining operations installed on a cable tray.

The point is that you need to use the NEC table. NEC is not a cafeteria where you can pick from the menu you want to use and not others. If the condutors are not one of the listed ones and the cable type is not one of the ones that is identified by the NEC in the 392, then you are using a cable that is not recognized by the NEC.

Not that I agree with it, but it is just so.

 

[TxEngr]

Canadian Standard

Canadian Standard

Teck-90 Cable is primarily used in Canada. The ampacity cited is from the CEC Part 1, Tables 1 & 2. So the key question is – what country are you using the cable in? If Canada, then follow the CEC code. If it is similar to the NEC and the cable must be rated for 125% of FLA, then you’ll need to bump up to the next cable size (400 or 500 MCM) to meet the requirements. But I’m no expert on the CEC so maybe some others can contribute here.

If you’re in the U.S., then your bound by the NEC as Weressl said, and there is no listing for Teck-90 cable. There probably should be since it’s a great cable, but it isn’t.

For those not familiar with Teck-90 cable, it’s similar to interlocked armor cable but has both an outer and inner PVC jacket around the armor. This provides additional protection to the cable in the event of damage to the jacket and is great for environments which can be wet, like paper mills and other industrial plants. It’s not real popular here in the States, but very popular in Canada.

 

[kenaslan]

Yes this project is in upper Canada. Up by the Artic Circle. I am mostly familiar with the NEC but most of the jobs are international. Most of the international companies require the use of the NEC however Canada uses the CEC.

 

[benaround]

NEC does not cover installations in mines.

 

[nakulak]

the nec doesn't cover "installations underground in mines and mining surface machinery". OP didn't make it clear exactly what this was for (its possible that it is covered in NEC (if NEC is the code that applies)