If you are engaged in the installation of power transmission, etc., all these activities come under services, meaning you will provide services to your customers in different plants or industries and on their premises.
One thing I want to suggest to you is that nowadays, most of the industries are asking for PF and ESI liability. When someone provides services to the industry, it is mandatory that if you are allowing someone to work inside your premises, then it is their responsibility to complete all compliances of the principal employer. In that case, they will ask you to provide their PF and ESI details.
So, first of all, you should go for PF and ESI compliances...
Regards,
Harsh