Are you working in the electrical contracting field?
Are you designing electrical systems?
Are you interested in learning about the different electrical installations On-Site?
Are you working in the MEP field?
You must read this post if your answer is Yes to any of the above questions.
Firstly, let us know what the electrical panel schedule is.
Before telling you the answer, let us imagine that you are supervising an electrical team together.
This team is responsible for installing the electrical containments (either embedded or exposed conduits in a specific zone, for simplicity, I will assume the area is a basement floor, and the installations will be exposed pipes).
These electrical installations will surely include the electrical wiring for the lighting and small power systems.
You will need to install 20 lighting fixtures in the basement and ten weatherproof socket outlets.
You will know these 20 lighting fixtures are looped together on the same circuit number or connected to different circuits from the electrical lighting shop drawing.
Let us say these 20 lighting fixtures will be connected to a lighting distribution panel name LP-B-01, and the number of the circuits is 5 & 8.
So, the circuit numbers will be LP-B-01/5 & LP-B-01/8, respectively.
LP means Lighting panelboard, B means Basement floor, 01 is the panelboard number, and 5 or 8 is the circuit number.
But to give proper instruction for your electrical team to proceed with the installations, you need to know the cross-section area of the wires of both circuits 5 & 8.
Plus, you need to know the conduit size, type, EMT, RGS, …etc.
Moreover, for checking and confirming the electrical load of a circuit, especially in the shop drawing preparation stage, you need to know each outlet’s wattage.
You will find the answer to the above questions and more in the electrical panel schedule drawing.
The same is also applied to the outlets of the small power circuit.
What other information can you get from the electrical panel schedule?
From the attached photo for a sample of an electrical panel schedule, you can see that we can know the following information:
01- The panel name
02- The service voltage to this panel. 230/400, or 110220,…etc.
03- The number of ways that exist in this panel and the frequency of the network connected to this panel.
04- The panel location, like the floor and room names.
05- The mounting type of the panel, surface mounted, recessed mounted, semi-flush,..etc.
06- This panel is powered from which panel/source.
07- The cross-section area of the feeder cable to this panel.
08- The number of outlets connected on the same circuit. (not all designers put this information)
09- The cross-section area of the circuit’s wires/cable.
10- The ampere rating of the main circuit breaker of the panel.
11- The type of the main circuit breaker of this panel, MCB, MCCB, or any other type.
12- The feeder entry is a top entry or bottom entry, and its cable type.
13- The ampere rating of each circuit’s circuit breaker exists in this panel.
14- The type of breakers of each branch circuit. Whether it’s an MCCB, MCB, ELCB, RCCB…etc.
MCCB: Moulded Case Circuit Breaker.
MCB: Miniature Circuit Breaker.
ELCB: Earth Leakage Circuit Breaker
RCCB: Residual Current Circuit Breaker
15- The type of loads on each circuit, whether single-phase or three-phase loads.
16- The color of the wires/circuits of each phase, whether they will be Red, Yellow, Blue, Black, or they will be Brown, Black, Grey, or Blue.
In the Old British Standard, RYB, the neutral will be black, while in the newest British/IEC Standard (BBG), the neutral color is blue, and the phases’ colors are Brown, Black, and Grey, respectively.
17- The number of available spare breakers inside this panel.
18- The number of available spaces inside this panel.
19- The total connected load on each phase of the panel.
20- The total connected load on the panel.
21- The demand factor of this panel.
22- There’s a phase balancing on this panel or not.
23- Some designers also put the circuit’s total length from the panel board until the last outlet.
From the previous, you can conclude why the electrical panel schedule is one of the most important drawings in electrical systems.
Now I will give you some bonus points to help you avoid many problems during the panel board’s installation process.
A- You need to make sure the panel’s location in the electrical panel schedule is the same in the electrical system layout is the same in the architecture layout.
B- You need to ensure the number of outlets connected to the same circuit is identical between the electrical panel schedule and the system layout.
C- You must have enough spare breakers & space as per your project’s specifications.
D- The more breakers you have in the panel, the more size or space required for the panel board.
E- Try to achieve a phase balancing between the three phases as much as you can.
F- Before ordering the cables or wires to any circuit, you need to confirm its colors and cross-section area per the latest approved electrical panel schedule.
G- During the dressing process of the electrical wires and cables inside the panel, you need to ensure the latest approved panel schedule is attached to the panel board, as without it, the electrician can’t provide proper tagging for each circuit.
H – If you are a contractor and need to order the wires/cables based on the total length available in the approved panel schedule, you need to cross-check this circuit’s full length from the CAD file of the system layout.
This is mainly for the electrical lighting circuits because maybe the designer who prepared this panel schedule calculated the circuit’s length based only on the horizontal distance and didn’t consider the wire/cable length required for each outlet.
Suppose you have lighting fixtures in a false gypsum ceiling, and the distance from the false gypsum ceiling to the concrete soffit is 60cm.
So, for each electrical lighting outlet, you need to consider an additional length for the wires as follows: 60cm+60cm+additional length to terminate these wires to the fixture (ex: 30cm).
So the total length=60+60+30+30=180cm for each wire/cable connected to this lighting outlet.
I hope you find this article interesting. If yes, kindly leave a comment to motivate us, and share this article with your connections.
Here is a list of the electrical tools which will be required to complete the termination of the panel:
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