20 questions on city and guilds 2396 exam with answers paper 8
Paper 8 of 8 for our city and guilds exams section.
The city and guilds is a difficult exam and you will need all the help you can and a good knowledge of the BS7671 here is some information on the june 2017 exam.
Cable Design Calculations
Candidates on the whole show a good ability in the application of circuit design for both live
conductors and cpc. Some candidates undersized the conductors as they did not determine
the design current correctly. Some marks were still awarded, in this situation, for procedure.
Surprisingly, a number of candidates did not show all of their calculations when justifying the
cable current capacity but instead simply sized for voltage drop. As the process carries marks,
these candidates would not have scored the maximum available.
In addition, quite a number of candidates would provide a detailed set of calculations but
forget to actually state the conductor size selected.
Candidates generally apply a good understanding of design earth fault loop impedance and
the application of the adiabatic equation as Chapter 54 of BS 7671. In contrast to previous
series’, a large proportion of candidates did conclude that their circuit calculations were
acceptable instead of simply showing calculations.
Conclusions to questions are as important as the calculations used to arrive at an answer. A
large part of the design process is justification of sizes selected. Candidates are encouraged
to conclude their selections by making comparisons to permitted and/or calculated values.
Candidates must be made aware of the two forms of adiabatic equation and where it is
suitable to apply each. Incorrect use of the equation requires a candidate to perform more
calculations than is required for justification and, if looking at the wrong Chapter in BS 7671,
incorrect values of ‘k’.
Candidates must also be very careful when applying temperature factors to calculations for
maximum earth fault loop impedance values. Candidates are encouraged to apply factors
during the design process then directly use the data within BS 7671 for comparison. In this
situation, the application of further factoring as Appendix 14 is not required, as temperature is
already compensated for.
Care must also be taken when using data within the IET On-site
Guide, as these values are also adjusted for temperature. As a result, some candidates made
temperature compensations twice. Candidates are encouraged to use data within BS 7671 for
design procedures.
Knowledge of BS 7671 (Design)
A working knowledge of BS 7671 is required by all candidates. Some candidates are able to
recite the requirements of BS 7671 but are unable to demonstrate how these requirements are
applied by using examples. Candidates at this level must be able to interpret requirements.
Quoting regulation numbers only is not a suitable response.
One question requiring candidates to explain why Additional Protection is required on certain
circuits produced a variation in answers but very few candidates were able to explain this with
many simply quoting where it is required.
Many candidates were able to determine a circuits short circuit capabilities showing a vast
improvement over previous series’ containing similar questions.
The vast majority of candidates answered questions relating to Fundamental Principles and
General Characteristics very well.
The majority of responses to one question, relating to protection against fire and thermal
effects, were simply quotations from BS 7671 with little regard to the risks associated with
installed equipment in escape routes.
Knowledge of BS 7671 (Selection and Erection)
A question relating to isolation and switching was generally very well answered. Some
candidates however seem unable to provide examples of such devices for isolation and
switching using practical situations. This led to many scoring half the marks on offer as the
question clearly requested examples. Many candidates seem to confuse the requirements for
isolation with those for switching for mechanical maintenance.
Few candidates were able to make a correct and accurate design and selection of protective
conductors using information within the question. Many answered giving generic ranges of
suitable conductors ignoring key detail.
All Other City and Guilds 2396 Electrical Design Past Papers
Past Paper: City and Guilds 2396 Electrical Design Past Paper
Past Paper: City & Guilds 2396 Electrical Design Past Paper 2
Past Paper: City & Guilds 2396 Electrical Design - Past Paper with ANSWERS
Past Paper: City & Guilds 2396 Electrical Design Past Paper 3
Paper 8 of 8 for our city and guilds exams section.
The city and guilds is a difficult exam and you will need all the help you can and a good knowledge of the BS7671 here is some information on the june 2017 exam.
Cable Design Calculations
Candidates on the whole show a good ability in the application of circuit design for both live
conductors and cpc. Some candidates undersized the conductors as they did not determine
the design current correctly. Some marks were still awarded, in this situation, for procedure.
Surprisingly, a number of candidates did not show all of their calculations when justifying the
cable current capacity but instead simply sized for voltage drop. As the process carries marks,
these candidates would not have scored the maximum available.
In addition, quite a number of candidates would provide a detailed set of calculations but
forget to actually state the conductor size selected.
Candidates generally apply a good understanding of design earth fault loop impedance and
the application of the adiabatic equation as Chapter 54 of BS 7671. In contrast to previous
series’, a large proportion of candidates did conclude that their circuit calculations were
acceptable instead of simply showing calculations.
Conclusions to questions are as important as the calculations used to arrive at an answer. A
large part of the design process is justification of sizes selected. Candidates are encouraged
to conclude their selections by making comparisons to permitted and/or calculated values.
Candidates must be made aware of the two forms of adiabatic equation and where it is
suitable to apply each. Incorrect use of the equation requires a candidate to perform more
calculations than is required for justification and, if looking at the wrong Chapter in BS 7671,
incorrect values of ‘k’.
Candidates must also be very careful when applying temperature factors to calculations for
maximum earth fault loop impedance values. Candidates are encouraged to apply factors
during the design process then directly use the data within BS 7671 for comparison. In this
situation, the application of further factoring as Appendix 14 is not required, as temperature is
already compensated for.
Care must also be taken when using data within the IET On-site
Guide, as these values are also adjusted for temperature. As a result, some candidates made
temperature compensations twice. Candidates are encouraged to use data within BS 7671 for
design procedures.
Knowledge of BS 7671 (Design)
A working knowledge of BS 7671 is required by all candidates. Some candidates are able to
recite the requirements of BS 7671 but are unable to demonstrate how these requirements are
applied by using examples. Candidates at this level must be able to interpret requirements.
Quoting regulation numbers only is not a suitable response.
One question requiring candidates to explain why Additional Protection is required on certain
circuits produced a variation in answers but very few candidates were able to explain this with
many simply quoting where it is required.
Many candidates were able to determine a circuits short circuit capabilities showing a vast
improvement over previous series’ containing similar questions.
The vast majority of candidates answered questions relating to Fundamental Principles and
General Characteristics very well.
The majority of responses to one question, relating to protection against fire and thermal
effects, were simply quotations from BS 7671 with little regard to the risks associated with
installed equipment in escape routes.
Knowledge of BS 7671 (Selection and Erection)
A question relating to isolation and switching was generally very well answered. Some
candidates however seem unable to provide examples of such devices for isolation and
switching using practical situations. This led to many scoring half the marks on offer as the
question clearly requested examples. Many candidates seem to confuse the requirements for
isolation with those for switching for mechanical maintenance.
Few candidates were able to make a correct and accurate design and selection of protective
conductors using information within the question. Many answered giving generic ranges of
suitable conductors ignoring key detail.
All Other City and Guilds 2396 Electrical Design Past Papers
Past Paper: City and Guilds 2396 Electrical Design Past Paper
Past Paper: City & Guilds 2396 Electrical Design Past Paper 2
Past Paper: City & Guilds 2396 Electrical Design - Past Paper with ANSWERS
Past Paper: City & Guilds 2396 Electrical Design Past Paper 3
