Breakers & MCCB

Question 1

Name 4 trips on a breaker

Answer 1

1. Under V
2. Over I
3. Anti-shock
4. Position interlock

Question 2

Brreaker

What 3 levels does the over current breaker have?

Answer 2

• Long time delay
• Short time delay
• Instantaneous

Question 3

What does the Position interlock breaker do?

Answer 3

Stops breaker being racked in or out

Question 4

What 2 ways can a breaker be operated?

Answer 4

• Manual
• Automatic

Question 5

What 5 maintenance routines should be done on breakers?

Answer 5

1. Inspect earth bonding
2. Measure earth bonding
3. Clean & inspect
4. Insulation resistance test
5. Clean cubicle

Question 6

Name 4 defects found on breakers

Answer 6

1. Blown fuses
2. Discrepancy switches broken
3. Limit switches broken
4. Jammed breaker

Question 7

What 2 frame sizes do MCCB’s come in?

Answer 7

• 100 amp
• 250 amp

Question 8

Name 5 safety devices on MCCB’s

Answer 8

1. Thermal mag trip
2. Manual trip
3. Electro-mag trip
4. Current limiting fuses
5. Residual current devices