According to Vol.1 Chap. 3 we studied that, grounding in any circuits creates one point that can be safely touched. But what would happen if we touch the upper terminal of the load and at the same time by the other hand we touch lower end of the terminal. considering different cases.

1. Circuit is grounded such that lower end of the load is grounded.
2. Circuit is not grounded but being grounded we are touching the terminals.

 

grounding in any circuits creates one point that can be safely touched

As long as that one potential is the only one touched, then that electrical potential will always be safe.

Your example of touching two voltage points at the same can easily be unsafe. Grounding the "lower" end of the load will not change or lessen the hazard. The size of the potential difference creates the danger. Having a ground reference likewise does not make the potential differences more of less safe. Having a potential tied to ground will not decrease the potential (and therefore shock hazard) simply because of that. A difference of, say, 100 volts is quite dangerous with or without a ground reference. Put another way, grounding one voltage point does not make the voltage difference any less dangerous.

 

can we assume that, we are in parallel with the load resistance.

 

It's not good practice to physicially "touch" a powered circiut, If one hand is on saferty ground the other hand better be in your back pocket.

 

Best Practices would refer you to the good old "One-Hand-Rule" where you should always keep 1 hand behind your back or in your pocket. This insures that you do not create a difference of electrical potential across your body, therefore allowing current to flow across the body.

Be safe!

___________________________

Jim Williams

http://www.learnelectronicsathome.com/