Understanding Voltage Between Hot and Ground in Electrical Connections

In summary, the conversation discusses the existence of voltage between hot and ground and how it is possible for a tester screwdriver to light up when applied to a voltage. The answer is that there is enough current due to the capacitance of the body or device to light up the neon lamp. The conversation also mentions that in most electrical systems, the neutral is grounded at the switchboard and that the Earth and all grounded surfaces act as one electrode of a capacitor while the person and the instrument make up the other electrode. Finally, it is explained that all materials conduct small current on high voltage due to the working of a capacitor.
  • #1
MarkWW
How exist voltage between hot and ground?
How we are connected to ground through wood floor, building when we use tester screwdriver?
 
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  • #2
Hello Mark - I believe due to language issues, you question is not too clear.

What do you mean by tester screwdriver - a voltage detector? There are different types, can you show a picture or link to the type you are thinking of?
 
  • #3
I think he means...

Using an old fashioned neon testing screwdriver the bulb lights up when it is applied to a voltage (e.g. 240V AC). My finger on the other end of the screwdriver is not (apparently) connected to ground when I am standing on a wooden floor. So how come the bulb lights up?

R0544853-01.jpg
 
  • #4
There is just enough current due to the capacitance of your body, or in the device, to light the neon lamp. Similarly the non-contact types use current into a capacitance to detect a time varying E field. These are so sensitive they can usually detect static generated by rubbing the device on your clothes.
 
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  • #5
Hello Mark - I believe due to language issues, you question is not too clear.

Where is potential difference between hot and ground?
How we close circuit when connect hot and ground wire (I do not know path of current)?

There is just enough current due to the capacitance of your body, or in the device, to light the neon lamp.

Same question, how circuit is closed without ground?

ZOhFD0f.jpg
 

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  • #6
MarkWW said:
Where is potential difference between hot and ground? How we close circuit when connect hot and ground wire (I do not know path of current)?

because the neutral is, in MOST electrical systems, grounded at the switchboard

MarkWW said:
Same question, how circuit is closed without ground?

same answer...

Windadct said:
There is just enough current due to the capacitance of your body, or in the
device, to light the neon lamp.
 
  • #7
The Earth and all grounded surfaces make one electrode of a capacitor - you and the instrument make up the other electrode, the air, shoes, (insulating things) make up the dielectric.

When you open a capacitor - there is no conductor between the two terminals.
 
  • #8
It means that all materials conduct small current on high voltage, even clothes, floor, wall...
 
  • #9
"Conduct" is not the word to use here. It is how a capacitor works.
 

1. What is the purpose of understanding voltage between hot and ground in electrical connections?

The purpose of understanding voltage between hot and ground in electrical connections is to ensure the safety and proper functioning of electrical systems. Voltage between hot and ground can indicate potential hazards or issues with the electrical system that may need to be addressed.

2. How is voltage between hot and ground measured?

Voltage between hot and ground is measured using a multimeter or voltmeter. These devices measure the potential difference between the hot wire, which carries the electrical current, and the ground wire, which serves as a safety measure to prevent electrical shocks.

3. What is considered a safe voltage reading between hot and ground?

A safe voltage reading between hot and ground is typically between 0-5 volts. Any reading above this range may indicate a potential electrical hazard and should be investigated further.

4. What are some possible causes of high voltage between hot and ground?

High voltage between hot and ground can be caused by a variety of factors, such as faulty wiring, damaged appliances, or power surges. It can also be a sign of a malfunctioning electrical system and should be addressed immediately to prevent potential hazards.

5. How can understanding voltage between hot and ground help prevent electrical accidents?

By understanding voltage between hot and ground, individuals can identify potential hazards or issues with their electrical system and take appropriate measures to prevent accidents. This can include repairing faulty wiring, replacing damaged appliances, or contacting a professional electrician for assistance.

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