Interference issue in CCTV due to Grounding

Interference issue in CCTV due to Grounding

Most of small size CCTV installation faces various type of interference issue. Most of Home, jewellery shop, grocery shop, youth hostel …… etc.

There are several factors that can cause interference problems in a security camera. Below is a list of some of them:

1. Use of improper power supply.
2. Use of poor quality cables
3. Use of poor quality cameras
4. Use of poor quality converters
5. Incorrect grounding
6. Camera Warm Up
7. Poor connections
​8. Lack of adequate lighting

In this article we understand Famous issue 5. Incorrect grounding.

If grounding is done improperly, you may see bands rolling on the screen, if this is the case, there is an interference problem called the ground loop.

This problem basically occurs when the camera, DVR or power source groundings are made at distinct points that have different resistances, this causes an effect called a ground loop.

To solve the ground loop problem simply ground the equipment to the same common point (ground bus) or leave one side (camera) without contact with the ground.

A practical example would be to place a wood, plastic or other insulation material on the back of the camera mounting bracket so that it does not come in direct contact with the post or wall that is installed.

Now only that if we rectify Earth & Neutral line of main voltage, the issue is rectified.

Neutral:

Neutral is the normal”return” wire.

In systems where the load is supplied from only one Hot (or “Live”) wire, the Neutral completes the circuit and carries current back from the load to the power station.

Neutral is a conductor that carries current in normal operation.

Neutral represents a reference point within an electrical distribution system.

Earth:

Earth or Ground wire is a safety protective wire for the human body and electrical equipment from fault conditions.

Earth is a conductor that carries no current in normal operation.

Earth is a conductor that carries current under fault conditions such as insulation breakdown that occurs within electrical equipment.

In a polyphase (usually three-phase) AC system, the neutral conductor is intended to have similar voltages to each of the other circuit conductors, but may carry very little current if the phases are balanced.

The United States' National Electrical Code and Canadian electrical code only define neutral as the grounded, not the polyphase common connection. In North American use, the polyphase definition is used in less formal language but not in official specifications. In the United Kingdom the Institution of Engineering and Technology defines a neutral conductor as one connected to the supply system neutral point, which includes both these uses.

As per Indian CEAR (Central Electricity Authority Regulations, CEAR came into effect 20 September 2010, in place of The Indian Electricity Rules, 1956.) neutral conductor means that conductor of a multi-wire system, the voltage of which is normally intermediate between the voltages of the other conductors of the system and shall also include return wire of the single phase system.

All neutral wires of the same earthed (grounded) electrical system should have the same electrical potential, because they are all connected through the system ground. Neutral conductors are usually insulated for the same voltage as the line conductors, with interesting exceptions.

Keep in mind The camera also requires a minimum current, which is usually less than 1A (ampere) for our example of a traditional CCTV camera.

The indication of the electrical current required for the camera to operate must be in the product manual, consult your distributor to be sure about the consumption of the camera, because in some cases with the use of infrared illumination the required current may be higher.

May this issue you face during final commissioning or after handover. Solutions remain same.

To know more visit http://arindamcctvaccesscontrol.blogspot.com/2014/01/ground-loop-problems-in-camera-output.html