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.