How to Join the Gas Safe Register
Written by James Walker · Last reviewed 16 August 2026
James Walker has 2 degrees in construction (BSc (Hons) Building Surveying · MSc Environmental Design of Buildings) and an extensive background in issue resolution, resolving over £4 billion of consumer issues.
The short answer
- Registration is a legal requirement for carrying out gas work. It is not a quality mark.
- You need current ACS qualifications for each category of work you intend to do.
- Categories are specific: domestic boilers, cookers, fires and commercial work are separate.
- Registration is renewed and qualifications must be kept current.
- Working on gas unregistered is a criminal offence.
The qualification route
Most entrants go through ACS (Accredited Certification Scheme) assessment, either after an apprenticeship or via a managed learning programme for experienced operatives from a related trade.
You are assessed per category. Passing domestic boilers does not qualify you for cookers or fires.
Registering
Once qualified, you apply to the Gas Safe Register with evidence of your ACS certificates, insurance and business details. Registration carries a fee and is renewed periodically.
You are issued a card listing exactly what you are qualified for, and customers are told to check it.
Keeping it
ACS qualifications expire and must be reassessed. Let them lapse and you cannot legally work on gas until you requalify.
The register also carries out inspections of registered engineers' work.
Why the categories matter commercially
Customers assume a Gas Safe engineer does all gas work. Being clear about your categories avoids taking on work you are not qualified for, which is both a legal and an insurance problem.
It is also a differentiator: an engineer who explains that categories exist is demonstrating exactly the diligence a customer wants.