Wiring Electrical Panels - 4 Flashcards
What is the purpose of fuses and circuit breakers?
to protect components against overcurrent.
What is NOT the purpose of fuses and circuit breakers on an electrical system?
Fuses and circuit breakers do not protect people working on the system.
What is the purpose of an electrical grounding circuit?
To prevent shock hazards that can occur from touching metallic parts of an electrical system.
What is electrical grounding the process of?
the process of using conductors to connect an electrical system to earth ground.
NEC Grounding Standards
Grounding the electrical system involves connecting metal parts that do not normally carry current to the system’s grounded conductor.
What are junction boxes used for in ground connections?
Junction boxes are often used to connect the external device grounds to the panel ground circuit.
If panels don’t have a ground bar, each ground is connected, by ground wire, to the what?
Main panel’s ground block.
The NEC requires conductors used in grounding systems to have what? (3 Answers)
- A Conductor made of copper, aluminum, or copper-clad aluminum
- Conductor is solid or stranded
- Insulation is green or green with yellow stripes
What are three types of ground connectors are there?
- Ground screw
- Ground Bar
- Ground Terminal Block
What should you do once a ground system is installed
Inspect and test before operation.
What is the first part of inspecting a grounding system?
a visual check of the ground wires.
What is the second part of inspecting a grounding system?
Check continuity with resistance setting using a DMM. (There should be continuity on all ground connections.)
What is the function of Wireways?
Wireways provide a channel through which wiring is routed between the electrical panel components. To keep it organized.
Wires should exit the wireway as close as possible to the ________.
Component.
What do wireways use to help protect the wiring and give the inside of the control panel a neat appearance?
Covers.
How many control devices are needed to make wireways not required in the control panel?
Less than six.
What are two methods of connecting wires to screw terminals?
- Straight wire method
* Lug connector method
What are the steps of the straight wire method?
- Strip a piece of insulation from wire.
- Twist end of wire if it is stranded.
- Placed stripped piece of wire under terminal clamp.
- Tighten screw to secure the clamp on the wire.
What are the steps of the lug connector method?
- Strip a piece of insulation from wire.
- Crimp a lug connector onto the stripped portion of wire using crimping tool.
- Attach lug under screw or clamp.
- Tighten screw to secure the the wire.
Where are wires terminated?
Inside an electrical panel at a terminal block or a component.
What must you do before terminating a wire?
The insulation at the end of the wire must be removed using a stripping tool.
What two types of wire stripping tools can you use?
- Manual Wire Strippers
* Automatic Wire Strippers
What happens if you nick the solid wire when stripping?
The mechanical strength of the wire gets reduced. May also cause the wire to break when connected.
If solid wires are nicked or strands are cut during the stripping process, what do you do?
Cut of the stripped portion of the wire and strip the wire again.
