Free Air vs. Conduit

Status
Not open for further replies.

wattup

Member
I have 535MCM Loco cable the manufacturer rates at 730 amp in free air.How do I derate for just three in a conduit?
 

tom baker

First Chief Moderator & NEC Expert
Staff member
Location
Bremerton, Washington
Occupation
Master Electrician
Re: Free Air vs. Conduit

1. portable cord can not be installed in a raceway, one exception for industrial locations, see 400.8 and 400.14
2. Locomotive cable is not a listed type portable cord.
3. A code accepted portable single conductor cable is Type W cable.
4. Welding cable is also not a listed cable.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: Free Air vs. Conduit

A lot of the DLO cable is dual listed as DLO/RHH or RHW. I would use Table 310.16 for 500kcmil for the 535.3 kcmil DLO cable. Note that the manufacture's ampacity rating is based on 90?C and you can't use that for most applications.
Don
 

pierre

Senior Member
Re: Free Air vs. Conduit

I have noticed a slight trend of late for some contractors trying to use a conductor/cable type that is not in Chapter 3 of the NEC, because of the higher ampacity ratings. I think the response that I have read here are excellent, they should be added to another thread area tittled "Forum Commentary". ;)
 
Status
Not open for further replies.
Top