welding cable

[dshelley]

A contractor installed a 300 HP motor the feeders to the motor are 2 3 phase paralleled set sof 1/0 Excelene +150 -50 welding cable in a 3 inch conduit.I said he can't do that that he had to size it according to 430 and 310 of the code. his arguement was that the UL listing allowed him to do it and showed the amperage rating of the welding cables but not inconduit. can he do this?
ps we are now getting high temps the closer we get to the conduit.

 

[iwire]

First thing is he cannot use 'welding cable' at all unless it is UL listed as a power cable and of a type listed in Table 400.4

Once he has the right cable he would have to size it per Table 400.5(A) or (B).

 

[augie47]

Bob, If it is only listed as a cable or cord (400.4) and not listed as a Chapt 3 insulated conductor (310.13), would 400.8(6) not prohibit it from being installed in conduit ?

 

[iwire]

Bob, If it is only listed as a cable or cord (400.4) and not listed as a Chapt 3 insulated conductor (310.13), would 400.8(6) not prohibit it from being installed in conduit ?

That is a darn good point.

So I will amend my answer, it has to have an insulation type listed in 310.13 and be sized per 310.16.

 

[izak]

the 'welding cable' that i have seen (we call it DLO) usually has a 'type RW' on it.
i have a chart for DLO cable, but it's values are much higher than in 310.16

 

[dshelley]

what about locamotive cable?

 

[zbang]

"locomotive cable" is not a recognised type. Some things called DLO or locomotive cable are also typed RW, W, or variations on them. Those designations are the ones that matter.

 

[don_resqcapt19]

The manufacturer's charts for that type of cable are based on 90?C and in free air (table 310.17). There are very few NEC applications where you can use that rating. You would use Table 310.16 and its associated rules for most NEC applications.

 

[james_mcquade]

I remember a similar post several years ago in which the individual who posted the thread
wanted to use welding cable for the servce entrance cable. He even gave the link to the cable. The welding cable manufacturer plainly stated in the data sheets that the cable was not rated for or intended for household wiring.

The cables were only rated for a 30% duty cycle. True, the size of the wire could take the load, but the insulation rating, and construction of the cable itself would not allow it.

The UL listing of any device means that the device has been tested and approved for that
particular purpose by "Under Writers Labratories". In this case its welding cable, not electrical wiring cable. The ul listing is therefore only good for welding cable applications. See the definition of "listed" in the code book.

If you are getting heat the closer you get to the conduits, its time to turn off the motor before its too late.

regards,
james

 

[don_resqcapt19]

The ampacity of the same size of cable that is listed only as welding cable and one dual listed as both welding cable and RHW or some other Article 310 wire type is the same. The only real difference is that in one case the manufacturer paid additional money to have the conductor dual listed.
I don't think it has anything to do with the duty cycle. if you look at the ampacity listed by the manufacturer, in most cases you will find that it matches the 90?C ampacity in Table 310.17.

 

[templdl]

If you can justify the use of the cagle with UL then the next issue is terminating the cable.
The common terminals that are found on devices are UL486 listed for use with class A and B stranding which I believe is 7, 19, 37, and 61 stranding.

If welders cable were allowed to be used as a conductor the terminals of the device are to be removed and the cable terninalted with crimp on lugs and then bolted to the device.