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Electrical Blueprints and Troubleshooting


Electrical Blueprints
Blueprints are an essential part of how we interpret an installation. It's usually the first thing we see, and the last thing we modify before leaving the job site. They are such an integral part of our profession, and it actually makes sense why we spend so much time of our apprenticeship learning about how to actually use them. Without a guide to show us the client`s intentions, or a solid direction for all trades to follow, it would be a production nightmare.


Construction Drawings

-show the intention of the architect or engineer
-shows the dimensions and the exact shape
-shows how the structure should be built
-shows which materials to use
-cannot be made until the owner has an idea of what he wants

Divisions: There are 17 Major Divisions in a Standardized Construction Specification.
Division #1 - General Requirements / Administrative (Apply to more than one division)
Division #2 - Site Work / Landscaping
Division #3 - Concrete / Framework

Division #4 - Masonry /Stonework
Division #5 - Metals/ Structure/ Steel Decking
Division #6 - Woods and Plastics
Division #7 - Thermal and Moisture Protection

Division #8 - Doors and Windows
Division #9 - Finishes
Division #10 - Specialties/ Lockers/ Movable Walls
Division #11 - Specialties/ Equipment

Division #12 - Furnishing/ Artwork/ Drapery
Division #13 - Special Construction/ Swimming/ Vaults
Division #14 - Conveying Systems/ Elevators
Division #15 - Mechanical/ Plumbing/ Heating & Air
Division #16 - Electrical
Division #17 - Miscellaneous

Organization of a Division
Part 1 - General
Part 2 - Products
Part 3 - Execution
-Specifications are extremely important. If looking at the drawing, and there is a contradiction regarding the spec book - the spec book wins the battle. The reason this is the case is because the specification book is usually the last item prepared, therefore reflecting the latest changes.

Working Drawings
Site/Plot - Top view, side walls, and driveways.
Plan - Top view, inside, dimensions.
Elevation - Front view, referred by compass points.
Sectional - Shows hidden detail beneath surface.
Detail - Shows small part of the entire project in great detail.
As Built - Reflects how the project was actually built.
Shop Drawings - Top, front, side view of an object. Shop drawings for electrical equipment will often include rated voltages and current draw.

Index Page
- First page of the package
- Lists all drawings
- Drawings within a division are numbered with a letter code

Title Block
Architect name, address of project, date the drawing was made, and seal of authenticity, person who made the drawing, person who checked the drawing, revisions, page number, and title of the drawing or sheet.

When a change is made, the revision is recorded in the revision block at the top, and new drawings are issued.

Is a ratio between the actual structure being built, and the drawing. You have to use a specified conversion method for units of measure. Question: If the scale is 1 : 200, and the point on the drawing measures 100mm, what is the actual size? Answer: 20 metres

Keys and Legends
To show what symbols are. Usually included in electrical drawings because of the huge range of items in use. The one shown above can be enlarged by selecting it. Each engineer is different, and this example shows that every installation can be job specific.

Can be represented in tabular form for easy viewing, and are our most important resources in a set of drawings.
1) Panel Schedules
2) Lighting Schedules
3) Transformer Schedules

There are three main types of electrical diagrams
1) Single Line Diagrams (Block, Riser)
2) Schematic Diagrams (Specific symbols used to show how a circuit operates)
3) Wiring Diagrams (shows the actual wiring connections)

Converting from Schematic to Wiring
- a simple numbering system is used
- number from left to right, then from top to bottom
- give all the same number to all wires that are spliced or connected to the same terminal.
- take one whole portion from start to finish (left to right) then proceed to branches.


Basic Troubleshooting Procedures

1) Interview the Operator
- the operator knows the machine the best
2) Verifying Facts
- sort out the facts from the fiction
3) Operating Sequence of the Machine
- either ask the operator or observe another similar machine
4) Manuals and Schematics
- go to a quiet area and read the manuals
5) Record for Changes
- many problems are caused by sudden changes. Check log for recent work.
6) Determine Symptom
- Go/No Go is easy to troubleshoot. Intermittent is the hardest.
7) Isolate the Problem
- Use the dividing method to prevent duplication
8) Logical Troubleshooting Sequence
- One person takes the lead. Follow logical pattern
9) Manufacturer's Guide
- Most manufacturers have a troubleshooting guide
10) Acting Hastily and it's Consequences
- Never hurry. Have a good reason to change a part.
11) Beyond the "Fix"
- A valuable trouble-shooter can anticipate problems, and prevent them from happening
12) Verifying the Results
- With any action there is a reaction. Change one thing at a time. It's easier to troubleshoot.
13) Substitution Troubleshooting
- To save downtime. Use a "known to be good" replacement part to prove the fault.
14) Comparison Troubleshooting
- An opportunity to compare one running unit against another for comparison.
15) Record Work Completed
- Record all work completed, and if new parts or alterations have been made the schematic must be altered (or remade) to reflect ALL changes made.

Lock out Tag out
1. Shut down equipment.
2. Open fuses, turn off energy isolating devices.
3. Apply lock out, tag out.
4. Render safe all residual or stored energy.
5. Verify the isolation and de-energization of machine or equipment.

6. Inspect work area and make sure components are capable of working correctly.
7. Check around machine to see if employees are within safe area.
8. Make sure locks are removed from appropriate personnel.
9. Notify employees before starting machine or equipment.