At a construction site there would be many objects that could puncture the skin. Multilevel container offices are still the preferred non-permanent structures used at building sites.
As mentioned by jlazucena these items translate to initial equipment cost and a larger substation space. However two units mean that you have operational flexibility.
Perhaps it would be useful to find out what CPVC is and a chemical engineer or the manufacturer should be able to enlighten you. For electrical installations PVC is used to provide insulation and when it is hardened can be used for limited mechanical protection
I like Bung's comment that everybody is right but I think Infomaniacs answer is correct to the question of kW vs kVA. The value does not change with the frequency - the speed of the machine is different and as mentioned the characteristics of the generator may be different for the different speeds.
