Wednesday, March 9, 2011

Electrical Services Color Codes

The following set of pictures gives some examples on the identification of the different electrical services inside a building.

Picture 1 – Example color codes for a few electrical services

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About the author:

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.

Visit this post, Electrical installation pictures, to see more electrical pictures.

Copyright Electrical Services Color Codes

Sunday, March 6, 2011

M & E Coordination

The few pictures that I show in this post is a demonstration of what can happen when proper coordination drawings are not produced prior to the commencement of the mechanical and electrical services installation in a multi-storey building.

Picture 1 – Improvised installation of electrical trunking, air-conditioning ducts, fire protection pipe work and a floor beam

About the author:

Somewhere among my previous posts, you can find examples of good coordination between the mechanical and electrical services installation.

However, here I wish to show you the opposite side of it. The above is not the worst case examples. I have plenty of pictures showing much worse scenarios which I will show you in future posts.

A reminder for the beginners in electrical installation works: Learn from the mistakes that other people have done and plan your work accordingly.

This is a very expensive lesson if you have to learn it from personal experience because rectifications, relocation or corrections in large installations can be very expensive and time consuming.

I do not plan to make this a long article. Regular visitors to this blog may have noticed that I have not been posting for quite a number of months.

A few have been asking me to continue posting articles and adding more topics.

So today I am back and you can expect to see some more pictures of electrical installations, good and bad.

There are readers who condemned a few of the pictures that I use to explain something.

They seem to have the opinion that using pictures with bad installation practices is like promoting bad installation practices.

With all due respect to their experience and expertise, I beg to differ on this matter and I think many would agree with me.

I also wish to remind the readers that none of the electrical installation works published here is my handiwork, whether the good ones or the bad ones. I did not do the wiring work; I did not do the trunking installation, etc.

I might have been the inspector with the responsibility to inspect or audit some the installation works.

However, when I show a picture, it does not necessarily mean that I say “this wiring work is a good example”. Or it is bad, unless I specifically say so.

It only means that there is something that the readers can learn from the picture.

Please bear in mind that different readers may learn different lessons from one single picture.

One of the primary objectives of this blog is to educate common people in how electrical installations work in real life. That is why I use “real” pictures.

In real life, the “real installations” (such as one’s own house wiring) are often “not that neat” and not that pretty.

It is very easy for me to show you pictures of neat and orderly house and office installations. I work in the construction business and I have tons of pictures of neat installations like that.

However, people often find it hard to understand the actual wiring in their own house or their own small offices because in most cases the wiring works are not new. They have been modified and they have been tampered with by people who either didn’t know enough or didn’t care enough about safety, or he tried to make the wiring works at a very low cost.

Whatever the reasons for the bad practices, the occupant who inherit the unit is faced with a wiring “system” that is hard to understand and is full of bad practices.

It is for this very reason that I use these pictures to explain how the wiring works. They are “real”.

That is all I have time for today. Enjoy the pictures and see you again in the next post.

Picture 2 – Electrical trunking and air-conditioning ducts

Picture 3 – Sprinkler pipes and trunking

Picture 4 – Telephone trunking, electrical and aircond duct

Picture 5 – Sanitary piping and domestic water pipes above electric trunking

Picture 6 – Sanitary pipes above electric trunking

Picture 7 – Trunking below sprinkler pipes

Picture 8 – Trunking below water piping

Picture 9 – Water pipes above trunking

You can see more pictures of electrical installation at this post, Electrical installation pictures.

Copyright M & E Coordination