What is bonding in electricity?
Electrical bonding is about connecting two or more metal objects to ensure safety by terminating potential differences between them. This way, there will be no current flow because there is no potential difference between two nodes or points.
What is Electrical Bonding?
Electrical bonding is implemented as a protective strategy against electric shock and arcing.
Electrical bonding is connecting all the exposed metal items intentionally and electrically. They may be wires, pipes, equipment, and any exposed conductor.
These metal items are not supposed to carry electrical current and we connect them together electrically to protect them from electric shock.
Not only electric shock, this practice can also reduce electrical arcing to minimum between two metal surfaces where potential differences exist.
Why do we need to eliminate the potential differences between two exposed metal surfaces or items?
When our electrical insulation fails, all the bonded (or connected) metal items and surfaces will have substantially equal electrical potential. This way, the people inside the room will be safe to touch the bonded objects because there will be no significant potential difference.
Hence, bonding electricity is a way to improve safety from dangerous potential differences.
Why Do We Need Electrical Bonding?
An electrical installation inside a building can cause dangerous situations related to electrical safety. One way to minimize this dangerous situation is by connecting all metal objects together to the main earthing to form an equipotential zone.
There are specific locations where electrical bonding is important to install such as fountains, bathrooms, and swimming pools.
For example, a swimming pool is a good ground since it is buried in the ground compared to the power panel ground. If all the swimming pool elements are bounded properly, the electrical current will less likely to find a path through the swimmer.
Electrical bonding makes a system capable of delivering the current caused by live or hot wire touching a frame or chassis of a device to the earth.
Electric shock will likely happen everytime we use our electrical devices. Everytime they are energized by electrical voltage, there will be residual voltage drop across the metal parts or conductors.
For bigger houses, factories, industrial sites, or mining sites, electric shock is considered a hazard or even an emergency case. This electric shock will be very dangerous if kept near flammable materials.
It can produce fire or even explosion depending on the material and its surrounding.
How Does Electrical Bonding Works
Remember about our study about open circuit vs short circuit?
Current will flow through a path with least resistance.
This is our main understanding before trying to understand electrical bonding.
We connect two metal exposed parts with a small resistance conductor to ensure the current will not flow through our electrical device or even worse, our body.
We should install an electrical bonding to every metal part that is not supposed to deliver or carry electrical current.
Furthermore, we will bond it to the earth to make sure there are no potential differences found, to keep us safe from electric shock or hazard.
Everytime a chance arises to energize conductor parts, we have to bond it to the earth.
For example: cables, wires, pipes, junction boxes, pipes, handrails, water, etc. More important, if there is a resident nearby exposed to the electric shock threats.
How to Make Electrical Bondings
The simplest electrical bonding is shown below:
This is done to make sure the table won’t give electric shock by delivering the current through the green-shielded conductor to the terminal cover. This method is known as direct bonding.
Let us talk more about direct and indirect bonding.
Direct bonding is an electrical bonding where we join two metal parts or conductors permanently. We can use welding, soldering, or brazing. Using tightened bolts to bond is also considered as direct bonding.
On the other hand, indirect bonding is less reliable since the parts are moving frequently hence we can not join them permanently.
We can make this using a jumper, metal strap, or simply cable.
Below is a bond strap often used to make an electrical bonding.
How we determine our electrical bonding depends on the potential current carried when there is an open supplied cable touching the respective metal part.