Electrical Safety Standards Quiz

What is the basic safety standard that applies to the protection of persons and livestock against electric shock in electrical installations?

• BS EN 61140

• BS EN 61400

• BS EN 61000

• BS EN 61200

According to BS EN 61140, what is the requirement for hazardous-live-parts under normal conditions?

• They shall be accessible.

• They shall not be accessible.

• They shall be partially accessible.

• They shall be accessible only to trained personnel.

What is the ripple-free voltage defined as in BS 7671?

• An rms ripple voltage of not more than 5% of the DC component.

• An rms ripple voltage of not more than 10% of the DC component.

• An rms ripple voltage of not more than 15% of the DC component.

• An rms ripple voltage of not more than 20% of the DC component.

Which of the following is NOT a protective measure generally permitted according to the document?

• Automatic disconnection of supply

• Double or reinforced insulation

• Electrical separation for the supply to one item of current-using equipment

• Manual disconnection of supply

What does an enhanced protective provision provide according to BS EN 61140?

• Basic protection only

• Fault protection only

• Both basic protection and fault protection

• No protection

The protective measures specified in Section 417, i.e. the use of obstacles and placing out of reach, shall only be used in installations restricted to:

• (i) skilled persons, or

• (ii) instructed persons under the supervision of skilled persons.

The protective measures specified in Section 418, i.e. non-conducting location, earth-free local equipotential bonding, and electrical separation for the supply of more than one item of current-using equipment, shall be applied only where the installation is under the supervision of:

• (i) skilled or instructed persons

• (ii) unskilled persons

• (iii) any person

• (iv) only skilled persons

If certain conditions of a protective measure cannot be met, what should be applied so that the protective provisions together achieve the same degree of safety?

• (i) supplementary provisions

• (ii) additional insulation

• (iii) increased supervision

• (iv) reduced voltage

The provision for fault protection may be omitted for which of the following equipment?

• (i) metal supports of overhead line insulators

• (ii) steel reinforced concrete poles of overhead lines

• (iii) exposed-conductive-parts with reduced dimensions

• (iv) all of the above

Automatic disconnection of supply is a protective measure in which:

• (i) basic protection is provided by basic insulation of live parts or by barriers or enclosures

• (ii) fault protection is provided by protective earthing, protective equipotential bonding, and automatic disconnection in case of a fault

• (iii) both (i) and (ii)

• (iv) none of the above