I find the existing software for the calculation of Electrical Installation difficult and long to use. Sometimes, I need to make a simple calculation or verification and I do not need to create a complete network to do it
Recently I have discovered some small calculators, some of them are too much simplified, but I find the idea good. There is for example…
voltage drop calculation from southwire
voltage drop calculation from csgnet
And also recently from Schneider for the calculation of several figures such as size motor, voltage drop, power factor correction, curve displayer, protection coordination, …
Sadly that only Schneider products are proposed
There is also Solutions Electrical, for example for the power factor calculation, but also other electrical engineering topics. It seems correct, but it is not free, so I have not tried it.
note: this post has been edited in Sept 2012 to update the links and images