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20 Cards in this Set
- Front
- Back
- 3rd side (hint)
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410 - Protection shall be provided by... |
Basic & Fault protection. Additional protection may be needed in special locations. |
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410 - Protective measures shall consist of one or more of following: |
Automatic Disconnection of Supply. Double or Reinforced Insulation. Electrical Separation for the Supply to one or more item of current-using equipment. Extra-low voltage (SELV & PELV) |
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410 - Most commonly used protective measure is? |
ADS |
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411.1 - Describe what ADS consists of... |
Basic protection by means of basic insulation, barriers/enclosures. Fault protection by earthing, bonding & automatic Disconnection when fault arises. |
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411.3 - What does Table 41.1 cover? |
Max disconnections times in which protective device should operate. |
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411.4 - In TN systems what must be fulfilled by characteristics of protective devices & impedances? |
Zs x Ia ≤ Uо x Cmin
Cmin = 0.95 |
Equation. |
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411.4 - In TN systems, the following types of protective device may be used for fault protection. |
An overcurrent protection device. An RCD. *When an RCD is used for fault protection, the circuit shall incorporate an overcurrent protective device.* |
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411.4 - What is Table 41.2 for? |
Max Zs for fuses for 0.4s disconnection time with Uo of 230V |
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411.4 - What is Table 41.3 for? |
Max Zs for circuit breakers for 0.4s disconnection time with Uo of 230V |
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411.4 - What is Table 41.4 for? |
Max Zs for fuses for 5s disconnection time with Uo of 230V |
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411.5 - In TT systems, one or more of following types of protective device to be used. |
RCD (preferred) Overcurrent protective device. *When an RCD is used for fault protection, the circuit shall incorporate an overcurrent protective device.* |
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411.5 - TT system, RCD is used for fault protection, the following shall apply. |
RCD shall meet times in Table 41.1 or 1s. RA x IΔn ≤ 50V |
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411.5 - TT system what is Table 41.5 for. |
Max Zs for RCDS for Uo of 230V |
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411.6 What does this section cover? |
IT system |
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411.7 what are nominal voltages for FELV. |
50V AC or 120V DC |
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411.7 Give example of source of FELV. |
Transformer with simple separation between windings. |
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411.8 Covers reduced low voltage systems, what are nominal voltages not exceeded? |
110V AC rms between lines. 3-phase is 63.5V to earthed neutral single-phase is 55V to earthed midpoint. |
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411.8 - What does Table 41.6 cover? |
Max Zs for 5s disconnection of 55V (SP) & 63V (3P) |
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412 - Double or reinforced insulation is a protective measure in which basic protection is provided by ..... & fault protection is provided by.... or Basic & fault protection is provided by.... |
Basic insulation. Supplementary insulation. Reinforced insulation between live parts & accessible parts. |
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413 - Electrical separation is a protective measure where basic protection is provided by.... & fault protection is provided by.... |
Basic insulation and barriers or enclosures. Simple separation of separated circuit form other circuits and earth. |
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