# Does a ground fault compromise the whole circuit?

Based on this picture, would a tree across the bottom wire of the circuit (the solid wire, not the dashed wire representing earth) cause the person to be electrocuted? Am I correct in thinking the tree would cause a voltage drop?

EDIT: To clarify, what would happen if a resistor was added to the bottom, solid wire?

• I don't see a tree? What do you mean by that? – abdullah kahraman Jun 16 '13 at 8:12
• @abdullahkahraman Sorry, I meant if a tree fell on the bottom wire - there isn't one currently in the diagram. – sdasdadas Jun 16 '13 at 8:25
• Do you mean adding a resistor from neutral to earth or in circuit with the neutral wire? A Neutral Earthing Resistor (NER) would have the effect of limiting earth fault current – Raggles Jun 16 '13 at 11:35

I assume the neutral wire is still unbroken after the tree is across it, in this case nothing would happen. The tree is already at ground potential, as is the neutral wire, as is the person. If the neutral conductor is broken then there will likely be an introduced earth fault impedance (either tree or person) and the load would see a voltage drop. If the person becomes the lowest impedance to earth then he will likely be zapped.

• Sorry, I'm a unclear about the term 'neutral wire'. Does that mean the bottom, solid wire or the bottom, dashed wire (the earth)? – sdasdadas Jun 16 '13 at 8:29
• The solid one at the bottom – Raggles Jun 16 '13 at 8:35

It appears the person in the diagram is touching the bottom wire, which is connected to ground. The person is not shocked because there is no potential from the wire being touched to earth ground underfoot.

I assume you mean if a tree (as in the plant) connected both the top and bottom wires, would the person be shocked then?

The answer is no, the potential difference would be across the portion of the tree that is making the connection.

Here's a video showing a tree branch shorting out high voltage distribution lines: