LV Bus duct insulation , which is better Epoxy or Mylar 1

[sramesh]

Good day to you

Low voltage 415V application Bus duct of 4000Amps, which type of insulation is better for 50 Deg Ambient (Gulf country) condition? Our specification is epoxy and vendor suggest MYLAR type. If some can share their experience/ knowledge on this will be helpful for us to decide. Thanks in advance

 

[7anoter4]

As Mylar is polyester find here an IEEE article about it:
Failure of polyester spacer at low voltage equipment
Summary: Arak Refinery plant of Iran confronted a number of failures of low voltage equipment. Our investigations after each event have shown that the phases of vertical busbars are connected together electrically and this caused flashover between them. Also, vertical busbars melted near the surface of spacers. Our inspections showed that degradation of polyester spacers left carbon on their surface and increased the surface conductivity between phases and neutral. So using general-purpose polyester in low voltage equipment at 50°C for long duration or higher temperature will cause surface conductivity.
See:

http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/6820/18299/00845516.pdf?temp=x

Regards

 

[sramesh]

Thanks for the information .. Regards