Ask Swami Candela

Dear Swami, How does one find the cross sectional area of a cable? In the book, "Electricity for Entertainment Electricians & Technicians," there is a formula in Appendix 4 to calculate voltage drop, and it uses the cross sectional area of the cable. Can you point me in the right direction? Signed, Looking for Direction Dear Looking, The universe is a bountiful source of information, but the internet puts it at your fingertips. For American Wire Gauges (AWG), you can find the cross sectional area of solid wire in Wikipedia on this page  and for international wire sizes, they are spelled out in IEC 60228. Two things to remember: 1. The cross-sectional area of stranded wire is calculated by adding all of the cross-sectional areas of the individual strands of solid wire that make up the stranded wire, and 2. The resistance of copper wire varies according to its temperature. The wire gauge charts typically use 30 degrees C (about 86 degrees F) as the ambient air t...

Dear Swami, A portable generator supply company supplied a generator for a show and told me to use the building ground since the generator is not close enough to any earth to pound in a grounding rod. I believe their generator is ungrounded because they only supplied three hot conductors (black, red, and blue) and a neutral conductor (white) with no grounding conductor (green). Does the generator need to be grounded? Do they need to provide a true earth ground that is bonded to a grounding rod? Or can they use the ground from the building to ground the generator? Signed, Floating Above Earth Dear Floating, The laws of man vary according to location, but the laws of nature are immutable. You should follow the local codes and regulations dealing with driving a grounding rod, but never violate the laws of nature, common sense, and safety. The reasons for grounding are three-fold: 1. to limit voltages due to lightning, line surges, or unintentional contact with higher voltage ...