Detailed study of Electrical Control panels-Part 1

If y'all haven't read the previous post click on the links below:

1)https://electricalmaniacs.blogspot.in/2017/09/electrical-control-panels- interesting.html
2)https://electricalmaniacs.blogspot.in/2017/09/detailed-study-of-electrical-control.html

In a control panel according to my experience, the high voltage stuff is usually kept on the upper part of the panel (this is not a rule though, you can keep them wherever you see fit). For example let's assume that we need some high voltage supply, say 480 V A.C, then it would make a lot of sense to keep the input power source at the top cause one of my reasons is that you obviously need to isolate or keep the electronics (components working at a lower voltage like PLC etc.) far away from the main supply. This is mainly to reduce the electromagnetic interference.

What I believe is that we need to know at least the working of the components that are used in the control panel. We will take all the topics one by one, first one is the Cables/Wires:

• Cables:
  They are one of the most basic components of control panel that are used for the purpose of interconnection.Now cables come in a lots of sizes and other stuff.So utmost care is needed in selection of proper cables for proper application.This looks very simple but if proper size of cable/wire is not selected ,then there will be heating due to which the wire gets damaged and if the wire gets damaged then the equipment connected to it is in the danger of getting damaged , it also could have disastrous circumstances for humans.There also is a lot of wastage of money.So it is important that we use proper cable size.Let's see how can i decide it.
• Before doing that let me first give you some basic info. About the control panels.In the control panels there are basically two kinds of circuits.

1)Power circuit*(contains higher voltage components).

2)Control circuit*(contains electronic and electronics works at much lower voltage level).

*This classification is given just for the sake of understanding this topic, A detailed explanation about both would follow in the later posts.

So, if you think logically both the circuits would have different ratings and would work in different conditions, so obviously the cables/wires used for their interconnection would be different.

Now, basically there are two kinds of wires/cables in a control panel,

1)Power cables (one's that have a higher rating,also called as FIELD DEVICES WIRES)

2)Control cables(used in the control circuit,also known as PANEL WIRES)

Basically the wire size is determined by generally by two basic factors(these are the basic , there are more smaller factors)

1) Current load of the wire.

2) Insulation rating of the wire.

• First make a list about what do you know about your panel.
• In the list ,first of all we should know what kind of load is supposed to be connected to our panel.
• Then what kind of power sources are present : A.C. / D.C. power for 3ph. OR 1 ph. (mostly H.V 3ph. A.C is used ).
• Next is the full load current.
• Then you need to know the circuit breaker size.
• The types of cables(PVC,XLPE,fire proved)
• Installation condition(whether it is underground,overground,trunking,tray or conduit)
• Distance / length of cable run from source to the load.

I think these are the things that you should know before starting building/understanding a panel.

Once you have all those data then we move on to the calculation step for the cable size.

There is a little formula for the calculation:

Ib≤ In ≤ Iz

Ib = Amperage load

In = Circuit breaker size

Iz = Current rating for cable/wire

Using the above formula you can decide the current rating of your wire.There is a whole post on that ,but let's not get into that now first just concentrate on the basics ,then we will get into the design aspect.

Till then stay cool!!

Keep asking why??!

Bye...(till the next post).

Note:Guys if you find something better than this please comment and i will be more than happy to     learn from you.

Thank you.