Single Line Diagrams & Electrical Classification

Explain how single line diagrams are connected to the site electrical safety program

1. With up to date, correct, lines we can lock out the right equipment

2. Provide the proper connecting info for upstream power distribution systems

3. Determine the capacity and flash hazard of downstream equipment. Flash Hazard determines level of PPE

4. Document the bus bracing for the MCC

5. Let us know if equipment is overdutied or not

6. Accuracy of these lines are audited for the electrical KEA

Explain the differences between class 1 and class 2 hazardous locations

Class 1 - Ignitable concentrations of flammable gases, vapors or liquids

Class 2 - Ignitable concentrations of Combustible Dusts

Class 1 Division 1 vs Class 1 Division 2

Div 1 - Ignitable concentrations of flammable gases, vapors, or liquids CAN exist all of the time or some of the time under normal operations

Div 2 - Ignitable concentrations of flammable gases, vapors, or liquids NOT likely to exist under normal operation

Identify Hazardous Locations in Department

HDL Process Tank Farm

LFE Tank Farm

Perfume Storage

Determine Rating of a device by observing the device nameplate

Devices should have labeling designating UL Hazard Classification

Explain what each symbol is in a Single Line for an MCC

Covered “Fed From”

Incoming Breaker (Frame and Trip)

Horizontal Bus Ampacity

Combination Starter Symbol (With frame, fuse size, starter size)

Extents of MCC

External Wiring

Wire Labeling

Field Disconnects

Motor HP

Transformer Size and Config