The conversion course is for the domestic gas installer who wants to convert their Domestic Core Gas qualification (CCN1) to Commercial Core (COCN1). Many of the modules from the CCN1 would have already been covered in assessment.

Entry requirements

  • This course can only be completed by operatives holding a valid CCN1 or COCN1 qualification
  • CoDNC01 re-assessment can take place up to 6 months before the expiry date. It must take place within the 12 months following the expiry date. It is illegal to install gas appliances without a valid qualification
  • Any operative undertaking gas assessment for the first time must complete a training programme.


  • Candidates can undertake re-assessment of any module up to 6 months early without losing any time.
  • Candidates must produce previous certificates as demonstrable evidence prior to reassessment.
  • All candidates who wish to undertake gas training and/or assessment must produce evidence of their qualifications.