Grounding and Shielding

Question 1

What 4 potential damages can grounding protect equipment against?

Answer 1

1) Shorting
2) Surges
3) Voltage fluctuation
4) Lightning

Question 2

What is grounding?

Answer 2

Connection between electrical equipment and the earth or a conducting body that serves in place of the earth

Question 3

What is protective earth?

Answer 3

Another common term for grounding

Question 4

What are 2 reasons grounding is implemented?

Answer 4

1) Protects equipment and personnel
2) Provides stability for instrumentation control system signals

Question 5

What is the difference between a clean and a dirty ground?

Answer 5

Dirty grounds are primary AC power supplies that are affected by spikes, surges, or brownouts

Clean grounds are isolated from dirty grounds to keep them free from interference. They are usually 24 VDC circuits

Question 6

What are the 2 types of electrical coupling?

Answer 6

1) Capacitive
2) Inductive

Question 7

What is the difference between shielded and screened wires?

Answer 7

Shielded wires: each wire has a shield and they are protected by an overall shield

Screened wires: single shield protects multiple wires

Question 8

Where do you ground a shield?

Answer 8

At one end only, never ground both ends

Question 9

What is the minimum size of wire used for grounding?

Answer 9

12 AWG

Question 10

What causes electromagnetic interference (EMI)?

Answer 10

Electromagnetic induction