CP1505: Off site Commissioning of current transformers

Formal title: Allowing ‘off site’ Commissioning of current transformers preinstalled in cut outs or switchgear at manufacture for use in low voltage (LV) installations

Current Status

CPC Consultation
Committee Decision
Awaiting Implementation


Code of Practice 4 (CoP4) details the requirements of Commissioning Metering Equipment for Settlement purposes in LV installations to be done ‘on site’. This is not always reasonably practical or physically possible and should be updated to allow ‘off site’ Commissioning of current transformers. In some installations current transformers are delivered in sealed units and have already been tested (and certain requirements of CoP4 confirmed) by the manufacturer ‘off site’. In these instances it may not be cost effective to complete all Commissioning tests ‘on site’. Furthermore, for some sealed units it may not possible or overly difficult to access the current transformers to perform the required tests. This introduces an un-necessary hazard to Commissing staff when the Commissioning could be better completed ‘off site’ in a more controlled and practical environment.


CP1505 was raised by GTC (ETCL & IPNL) on 12 March 2018. CP1505 was presented to the ISG for information on 20 March 2018 and to SVG for information on 27 March 2018. CP1505 was issued for consultation on 9 April 2018 with responses due by 4 May 2018. Following the CP Consultation a number of non-material amendments were made to the redlining in order to resolve concerns highlighted through responses (v0.2 available below).  The Assessment Report for CP1505 was presented to SVG on  29 May 2018 where it gained approval. The Assessment Report was presented to ISG on 19 June 2018, they decided to defer their decision requesting that ELEXON conduct further analysis into a concern which the ISG held regarding the CP.

Next Events

The Assessment Report for CP1505 will be presented to the ISG following further analysis requested.


Click on the X next to any of the icons to replace them with a short-cut link to the page you are currently on or search for a specific page.