Ground Rise Potential (GRP) occurs in every instance in which an earthed network becomes live.
It may not always be possible to protect the pole top worker and the ground worker simultaneously.
To ensure the equipment is fit for purpose the fault level, peak factor and tripping times of the installation must be known
The inclusion of jointed steelwork in the short circuiting current path will result in slower tripping times and less protection for workers.
Short-circuiting devices should be maintained to a standard that ensures it is fit for purpose.
Higher temperature levels are now allowed under IS EN 61230:2008 to accommodate lighter equipment. The following Tables may be helpful.
Even though Copper conductor is heavier and more expensive than Aluminium conductor, (Aluminium is aproximately 60% of the weight of copper) Copper conductor offers a far superior temperature range and fault level aspect. The equivalent Aluminium conductor has a larger CSA but offers aproximately 60% of the current carrying capacity and similar working temperature range.