For starters, if you carried out that kind of work in Ireland I can almost guarantee you you'd be sued.
The consequences of prosecution by regulatory authorities would pale into insignificance when you'd see the kind of damage a homeowner or their insurer would do to your business if you left them with a mess like that.
In general most kitchen installers I've come across here have a qualified electrician and a qualified plumber as part of the team. They float around dropping in and out as needed. Typically, they pay a visit after the existing kitchen has been stripped out and do all of the necessary electrical and plumbing work. The kitchen's fitted and the fittings are hooked up and wall plates put on etc.
A kitchen installer doing that kind of work here without a person who was legally competent to carry out such work would simply be signing their own bankruptcy paperwork. Basically, if the installation went on fire they would be fully liable for the direct and knock-on costs and the insurers do sue.
