Update on PAS 63100 and IET Code of Practice 3rd Edition

Our Standards define how certified renewable energy installations should be designed and installed. They are a benchmark for quality developed in close consultation with industry through independent technical Working Groups. Following the recent publication of PAS 63100, MCS has received a significant number of enquiries from installers wishing to understand how this might impact on their work and MCS certification for Battery Storage installations.


A message from the Battery Storage Working Group about the recent PAS 63100:2024 publication:

“Although not a British Standard, PAS 63100:2024 has been developed by BSI and sponsored by the UK government. It specifies requirements for fire safety in the installation of small-scale electrical energy storage systems (EESSs) in domestic dwellings using stationary secondary batteries as the medium for energy storage. This includes the location of Battery Storage products in a loft space.

The drafting of PAS 63100:2024 was undertaken with the assistance of a technical committee drawn from a wide range of interested parties. A draft of the document was also issued for public consultation last year.

The Chair of the MCS Battery Storage Working Group as a member of the BSI committee regularly fed back to the Battery Storage Working Group so that feedback from the working group could be considered by the committee during the drafting process.

Coinciding with this the IET has also recently published the 3rd edition of its Code of Practice for Electrical Energy Storage Systems which now states PAS 63100 “…should be considered.” (section 11.2.2) and, in terms of battery location PAS 63100 “…should be used” (section 11.2.3).

In relation to the immediate impact that these two publications have on MCS installers – PAS 63100 has no current standing in any UK regulations (such as Building Regulations) and is not directly referenced in the Battery Storage Installation Standard (MIS 3012). However, MIS 3012 does refer to the “latest edition of the IET Code of Practice” and so, indirectly, refers to PAS 63100 and associated requirements.

The language used in the IET Code or Practice allows for flexibility as it uses the word ‘should’ when referring to PAS 63100. In the IET Code of Practice ‘should’ is “…used for a recommendation. Recommendations indicate best practice, or a particularly suitable course of action.”

The MCS Battery Storage Working Group recognises that subjective language can pose difficulty to contractors who want to ensure compliance to Standards.

We can confirm that in the short term, there are no direct changes to MIS 3012 the Battery Storage Installation Standard. The Working Group will next meet in July where they will consider the requirements of PAS 63100 and if and how they’ll be directly incorporated into MIS 3012.

Any proposed changes will be publicly consulted upon.”