Posting a message to the forum will remove the above advertisement
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. angel While you're here, would you mind checking out our Electrician's Insurance section to see if we could save you a few quid? - Specifically our Van Insurance Deals and Public Liability Insurance Deals. Thanks for supporting the forum! angel

    5% Discount from for ALL members! - Click Here

Discuss very low pfc on submain board in the Periodic Inspection Reporting & Certification area at

Thread Status:
Not open for further replies.
Please make sure you checkout our forum sponsors, many do discounts for members and, they keep the forum free to use.
  1. lucus

    lucus Regular EF Member

    hi all hoprfully someone here can answer this question for me: i tested a sub mains today and i only got 0.35 KA is this normal for a submains as at the main mainsboard the pfc is 3.3 KA the main fuseboard has a rcd main switch so at the submain i had to use no trip pfc not sure is this makes and difference any imput would be great.
  2. Sintra

    Sintra The Innkeeper Staff Member

    Did you test Zs at sub main and if so what was this reading.
  3. lucus

    lucus Regular EF Member

    yes zs was 0.36 the submain is fed via a 6mm armoured cable
  4. marcusone

    marcusone Electrician's Arms

    Hi Lucus

    What was your Zs at the sub main ? It will be higher than at the origin so therfore the PFC will be lower.

    So as long as all protective devices throughout the installation have a breaking capacity equal to or more than the origin main protective device,then recording the origin PFC is good enough.

  5. pevvers

    pevvers Electrician's Arms

    That PFC would be for a Zs at the board at around 0.65 ohms. So not sure where you're going wrong there.... You should be getting a PFC of around 0.68kA if all correct.
Similar Threads - very submain board Forum Date
Debt recovery, there are some real are holes out there. The Electricians Arms Saturday at 11:35 AM
Very strange this one. Electrical Forum Oct 1, 2018
Thread Status:
Not open for further replies.

Share This Page

Electricians Directory Post a Domestic Job Post a Commercial Job