repair of security systems; installation of security systems; installation of security and safety equipment; installation, maintenance and repair of security and safety equipment; maintenance and servicing of security alarm systems; maintenance and servicing of security alarms; advisory services relating to the installation of security and safety equipment; maintenance of burglar and security alarms; installation of telecommunications apparatus; communications infrastructure construction; maintenance of communications equipment; installation of electronic communications networks; installation of communication equipment; installation of communications network instruments; installation of communications network apparatus; communications network apparatus installation; communications network instrument installation; maintenance and repair of communications systems; maintenance and repair of data communications networks; installation of telecommunications networks; installing of electronic communications networks; installing of telecommunications networks; advisory services relating to the installation of communication equipment; installation, maintenance and repair of hardware for data communication networks; installation, maintenance and repair of telephone and communication equipment; installation of electrical wiring for buildings; installation, maintenance and repair of electrical devices; installation of electrical apparatus; installation of electrical apparatus for buildings; installation, maintenance and repair of electrical and electronic apparatus and equipment; electrical equipment repair; repair of electrical equipment; repair and maintenance of electrical apparatus; repair of electrical apparatus; installation, maintenance and repair of apparatus and instruments for conducting, switching, transforming, accumulating, regulating or controlling electricity; electrical installation services; services of electricians; construction work relating to the installation and maintenance of electrical systems; installation, maintenance and repair of apparatus for supplying electricity; installation, maintenance and repair of apparatus for generating electricity; maintenance of consumer electrical appliances; installation of electrical apparatus or generators; installation of electric light and power systems; installation of machinery for generating electricity; repair of electrical appliances; maintenance and repair of electrical appliances; installation, maintenance and repair of electrical equipment; installation of electrical wiring; electrical wiring services; wiring services for telecommunications; telecommunication wiring services; telecommunication wiring; advisory services relating to the installation, maintenance and repair of mechanical and electrical equipment; maintenance and repair of electrical apparatus