I have a job that requires installation of a 500kw inverter in Canada. I'll be running DLO/RHW-2/RW90 wire. The wire specs rate the ampacity at ambient temp. 30c. I'm looking for a wire size rated for 400amp at 75C with. Do I use DLO 373 MCM or DLO 444 MCM. The 500kw puts out 1470amp at 200v. I'll be running 4 sets in a metal wireway. NEC allows up to 30 wires before de-rating, but the nec chart 310.16 only says up to 3 wires. I'm used to running THHN and the amp rating on that but this DLO MCM rating has me confused.
DLO/RHW-2/RW90 wire for pv install
- Thread starter xlh883
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- Illinois
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- retired electrician
I think you need at least 535 for 400 amps at 75?C. While T310.16 does not directly cover the conductor sizes for DLO, the ampacties in the table are the NEC ampacities. Wireways are a special case and you are premited to install up to 30 current carrying conductors without derating for fill.
- Location
- Illinois
- Occupation
- retired electrician
Well, 500 is rated at 380, so the 535 should be about 400 amps.
weressl
Esteemed Member
Use the wire as RHW-2 for calcualtion purposes and check with the AHJ if they accept extrapolation of the non-listed kCMIL size, othervise use the next smaller non-standard size.
I presume that the wire specifications you are refering to are the manufacturer's specifications. Since the NEC allows for engineered calcualations as an alternative I would suggest that the manufacturers specified current rating can be used within the specified installation parameters, such as in conduit, in cable tray, etc. If your installation method is not listed, then fall back to the NEC.
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