Reply From C & G Re Confusing Question.

[ccrowe]

I'd guess it's a reference to 522.6.8 which states

Irrespective of the depth of the cable from a surface of the wall or partition, in an installation not intended to be under the supervision of a skilled or instructed person, a cable concealed in a wall or partition the internal construction of which includes metallic parts, other than metallic fixings such as nails, screws and the like, shall:

(i)-(iv) all deal with mechanical protection
(v) be provided with additional protection by means of an RCD...

 

[IJWS15]

So does that mean I need RCD protection on my wall lights?

I have internal walls with steel studs!

 

[Spark123]

s there is a gap between studs, the steel won't be protecting the whole of the cable against penetration by drill, nail etc, so under the 17th edition it will need to be RCD.

 

[viewer]

I'm not a spark, but university lecturer and thus set lots of examinations. The wording of this question is not be acceptable as shown (- assuming that this is a stand alone question and not part of a sequence with a separate description of the scenario) . This should not have been accepted by the moderation panel and certainly would not be in my university. Clarity of questions is often a problem because it is easy to have a mental picture of a scenario when writing the question - one which others do not share. Moderation is achieved by the teaching team sitting together and swopping questions until ambiguities are all removed and the question is clear to everyone. Here there is no sense in the term 'metallic construction'; as posts have shown; it could refer to anything from a steel framed building to a shed.
OP, you're right - right to say that the question is confusing and right to question what is meant. In real life not questioning and making assumptions can be fatal. However you obviously passed with flying colours so genuine unambiguous congratulations.

 

[securespark]

Thank you!