conductor with varying size

[stallion2701]

Is there any code that indicates installing MV conductors of different size is not acceptable?If there is any code that violates this,I would like to use it to justify our intention to replace existing underground feeder.This cable are already old and obsolete(paper insulated).Thanks in advance....

 

[saladhawks]

If there was such a code, the utility that I work for would be in violation so many times that it would make you laugh. Not only are different size MV cables with the same insulation type spliced together, but PILC to Synthetic transition splices are very common.

 

[dpc]

As long as the smallest size used in the feeder is in compliance with any code requirements, you're probably OK as far as size. But if this falls under NEC, any splices generally must be accessible, except for direct-buried cable.

A splice in the middle of a conduit run is not acceptable.

 

[waross]

You may want to consider the effect of cable size and/or configuration changes on available fault currents, and fault current protection settings. In many instances the effect may be negligible, in some instances the effect may by an issue.
respectfully

 

[cuky2000]

Splicing different type of cable is a common practice in the utility industry.
As far I know there is not code violation splicing different type of cable with an appropriate joint such as the one enclosed by Prysmian (former Pirelli US)

http://www.fr.prysmian.com/fr_FR/ca...-1C_3C.pdf;jsessionid=MHQN2C0JLYV2DFYKJOPCFFA

Beware that the cable protection should consider the maximum temperature of the insulation.
On the other hand, paper cable still is available in the market.

 

[DanDel]

And PILC cable usually has a much longer lifespan than EPR or XLPE.