2365-625 (BS7671 + OSG)

When refering to external influences, code AA1 relates to

• ambient temp range -15 to +5 degreesC
• ambient temp range -5 to +35 degreesC
• ambient temp range -65 to +5 degreesC
• ambient temp range -60 to +5 degreesC

Identify the maximum tabulated Zs value for a 16A type 'B' mcb

• 2.42 ohms
• 2.73 ohms
• 0.87 ohms
• 1.87 ohms

In a TT installation, distribution circuits must disconnect within

• 5 secs
• 0.4 secs
• 1 sec
• 0.2 secs

a Ze value for an electrical installation can be found be taking a measurement at the...

• at the furthest socket outlet
• at the origin of the installation
• furthest point in the installation
• at the end of a circuit in the installation

a RCD operates on which one of the following principles

• magnetic operation caused by an imbalance between line and neutral
• thermal operation of a bi-metallic strip
• thermal operation caused by the fault current
• magnetic solenoid action caused by a short circuit between line and neutral

External Influence code 'AD1' requires equipment to be protected to..

• IPx2
• IPx0
• IPx1
• IPx5

When refering to external influences, code AA5 relates to

• ambient temp range -5 to +35 degreesC
• ambient temp range +5 to +40 degreesC
• ambient temp range -65 to +5 degreesC
• ambient temp range -15 to +5 degreesC

BS7671 states that 'electrical installations are arranged into circuits to....'

• allow higher distribution of power to the circuits
• allow for easu expansion without affecting total loading
• reduce electromagnetic interference
• allow easier access to the electrical installation

Identify the maximum disconnection time for a 230v AC fixed equipment circuit not exceeding 32A, as part of a TN system.

• 2 secs
• 40mS
• 5 secs
• 0.4 secs

For a 32A B-type mcb protecting an A1 ring circuit, the maximum (tabulated) Zs value allowed is..

• 0.35 ohms
• 1.37 ohms
• 0.72 ohms
• 2.96 ohms