How do you move from domestic to commercial gas work?

Sooner or later most established domestic engineers get the call: a plant room, a school boiler, a restaurant kitchen. The work pays better and the diary is steadier, but your domestic categories do not cover an inch of it. This guide maps the official route across, what the commercial tickets actually add, and the question the trade forums keep circling: is it worth it?

What are the two routes into commercial gas?

The ACS framework offers a full initial route and a changeover route. The initial route is the from-scratch path: a generic non-domestic core plus a sector core, COCN1 for commercial heating, CCCN1 for commercial catering or CCLNG1 for commercial laundry, each with at least one appliance assessment on top. The changeover route exists precisely for engineers like you: the scheme added its changeover cores to make transfer between gas sectors easier, so a domestic engineer does not restart from zero. You sit a shorter changeover core that credits what CCN1 already proved and assesses what commercial work adds.

How does the changeover from CCN1 work?

One structural point matters more than any single ticket. Commercial categories gained by changeover hang off your domestic core: the scheme's guidance is blunt that commercial catering categories cease to be valid when the CCN1 assessment expires. Going commercial does not replace your domestic renewals, it adds a second set on the same five-year cycle, and letting the domestic core lapse pulls the commercial scope down with it.

What do the commercial assessments actually cover?

• CIGA1: indirect fired appliances, the commercial boilers and heating plant most changeover engineers want first.
• CDGA1: direct fired appliances, and CORT1: overhead radiant plaque and tube heaters, the warehouse and workshop staples.
• BMP1: gas boosters and associated controls, and CGFE1: gas fuelled engines.
• ICPN1: installation of commercial pipework over 35mm diameter, the point where domestic pipework scope runs out.
• TPCP1A: strength and tightness testing and purging of pipework up to 1 cubic metre volume at up to 40 mbar; TPCP1 extends that to pipework up to 16 bar.
• None of this is covered by CENWAT. A first-rate domestic boiler engineer is simply not qualified for commercial plant until these are on the card.

Do you need experience before the changeover?

The framework itself asks for CCN1 plus appropriate domestic appliance assessments, and nothing else. Training providers and colleges commonly add entry requirements of their own on top: several state that changeover candidates must have been Gas Safe registered for a minimum of a year, or ask for evidence of working experience before accepting a booking. Treat those as provider requirements rather than scheme rules, and confirm directly with your chosen centre before you plan around them. The honest version of the same point: the changeover assessments assume you are fluent on the tools already, because they test the commercial delta, not the fundamentals.

What about commercial catering tickets (COMCAT)?

Catering is its own lane inside commercial, with its own core: CCCN1 on the initial route, CoDC1 on the changeover route. On top of the core, the appliance assessments run as the COMCAT series. CoCATA1 is the changeover appliance assessment and covers the COMCAT 1 and COMCAT 3 groupings, which between them take in ranges, ovens, boiling pans, fryers, griddles and grills, the bulk of a working kitchen line. COMCAT 2 (pressure water boilers and steamers), COMCAT 4 (fish and chip ranges) and COMCAT 5 (forced draught burner appliances) are separate assessments, and mobile catering adds an LPG changeover on top. Kitchens are where domestic engineers most often get asked to cross scope, because the cafe's boiler and its cooking line sit metres apart; until the catering categories are on your card, the answer on the cooking line has to be no.

Is moving into commercial gas worth it?

The forum answer is "depends who's asking", and for once the forums are right. The case for: commercial work generally pays above general domestic servicing because fewer engineers hold the tickets, the work runs on maintenance contracts and annual CP17 inspections that repeat like clockwork, and one good commercial client can anchor a diary the way thirty boiler services cannot. The case against: the tickets cost real money and most centres price commercial packages on enquiry rather than publishing rates, so get like-for-like quotes listing the exact assessments; colleges typically run the changeover core over two to three days with appliance modules on top; and every new certificate joins the five-year reassessment cycle beside your domestic ones. The deciding question is not the course, it is the work: engineers who changeover with a commercial subcontract or a maintenance contract already waiting recoup the outlay quickly, while a commercial ticket with no commercial pipeline is an expensive certificate in a drawer.

How do you keep the commercial paperwork side straight?

Commercial clients are audited in a way homeowners never are: insurers, environmental health officers and head offices all ask for the current report, and the record for each site has to be findable years later. That makes the admin habits you built on CP12s the most transferable asset you bring across. Manifold handles the commercial side the same way it handles domestic: each site's inspection history stored against the premises, renewal dates tracked so the annual visit is chased before it lapses, and last year's record on screen during this year's inspection.