User Tag List

Results 1 to 3 of 3

Thread: Current Transformer (CT) Secondary Wiring

  1. #1
    Join Date
    Jan 2006
    Location
    USA
    Posts
    312
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Current Transformer (CT) Secondary Wiring

    Does the CT secondary wiring need to be rated 600V for installation in a 120/240V panel?

    Is this considered Class 1 wiring subject to Article 725? Or does 300.3(C) cover this sufficiently?

    I ask because 725 point to 450, but CTs are explicitly excluded from the scope.

  2. #2
    Join Date
    Aug 2004
    Location
    Northern illinois
    Posts
    17,447
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I think one can make a good argument that CTs circuits are indeed class 1 circuits.

    Having said that, there does not seem to be an exception for the required OCPD in the transformer circuit found in article 725.
    Bob

  3. #3
    Join Date
    Jan 2006
    Location
    USA
    Posts
    312
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks. I don't think I could make a decent case against your Class 1 argument.

    Overcurrent protection is another item that points to 450.

    725.45(D) > 450.3(B) > Table 450.3(B) = 125% of primary current?

    But 450.1 Exception No. 1 excludes CTs altogether.

    I think the Code might be broken, hand me a sledgehammer.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •