Picture 1 – Example color codes for a few electrical services
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The three conduits with the color code bands in the above pictures are part of what we call in building works as electrical services.
However, electrical services are not the only ones that require some means of identifying what they are for.
Mechanical services also really need their piping, trunking, etc to be provided with some identification.
In some installations such as hospitals, there are so many services under the mechanical category. At certain locations in a hospital complex, it is almost impossible to know which pipe is for what. (Remember that an electrical G.I. (galvanized iron) conduit is just a metal pipe.)
During maintenance, long after we the construction people have completed and commission the building with all the mechanical and electrical services fully tested and operational, the maintenance people could be cursing us every week for not providing sufficient identification for each of the services inside the building.
During operation and maintenance of the building, insufficient identification on each of the services throughout the building can lead to serious accidents.
Why do I talk about mechanical services? Because they often run along the electrical services. Now and then the parts and materials between the two disciplines look and feel just the same.
A note for the beginners: the different colors of the wires to a three-phase motor or to a machine that use three-phase power supply is a form of color coding.
Now let us get back to the pictures: In Picture 1 above you can see three conduits with color bands on them.
The one the right side (nearer to the concrete wall) has got a six-inch band with two colors. Or you can call it three bands with the outer two in red and the center band in white.
This conduit is for one of the Extra Low Voltage services. It is for the audio-video cables. An example where you can find this would be a large meeting room or a conference room, or an auditorium.
These types of building spaces would usually have conduits and/or trunking to contain and protect the wiring cables to and from the microphone points, the speaker points, ceiling speakers, etc.
That is an example of what we call an Audio-Video system.
(Note: Extra Low Voltage (ELV) Services is a name usually used to categorize some electrical services. Examples may be the Audio-Video system I have just explained above, security systems like CCTV and card access systems, queue management system, etc. These systems are still electrical systems because they still run on voltage and currents to say it simply. However, they use very low voltages of less than 25 volts anywhere in their equipment and wiring.
Of course they still need to connect to the 240 volt building electricity in order to work.)
The purpose of the color bands is simple: to identify what system the conduit is part of.
Table 2 below show a table of the ELV services in a building with the respective colors of the bands shown.
Not all buildings use the same colors, but large organizations usually have some sort of standard color coding system that must be followed by all contractors that execute work under the control of that particular organization.
Table 2 – Table of color codes for ELV services
Note that the colors for electrical conduits and trunking are not listed here. As far as I know it is a general practice everywhere to use orange as the color code for those electrical conduits, trunking and cable trays, while the cable ladders are more often not painted.
The subject of color coding is simple so I am not going to drag this post any longer than necessary. Readers can just scan through the other pictures below.
Picture 3 – Labeling on electrical trunking
Any building of a signification size usually has a supply source backed by standby diesel generators. This supply is usually called “ESSENTIAL SUPPLY”. The label “ESS” spray-painted below the smaller trunking is used to convey that message.
In office buildings, a form of centralized UPS (uninterruptible power supply) may also be provided. In Picture 3 above, the trunking that carries the wiring to all 13A wall sockets backed a UPS supply has been labeled “UPS”.
Please do not underestimate the importance of these labels. When the electricity supply from the public mains has failed, the standby diesel generators kick in. So the cables and wiring that run inside the ESS trunking is LIVE.
That means all socket outlets supplied from this trunking is still live and DANGEROUS.
The UPS unit always takes supply from electrical boards backed by the generators. So the wiring inside UPS trunking are also just as dangerous.
If the standby diesel generators also fail to start, then the wiring inside the ESS trunking has no power and not live.
However, the wiring inside the UPS trunking still has power because they are backed by batteries of the UPS unit.
Picture 4 – Another picture of electrical trunking
Picture 5 – CCTV conduit
Pictures 6 – Conduits for some other ELV services. You can check against Table 1
Picture 7 – CCTV conduit also
Picture 8 – Audio-video system
Picture 9 – This is another method to label the ESS supply
Okey folks… I need to get back to my work. See you again the next time.
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