Hi everyone. This is Hus. In this video, I’ll show you how to use ASNZS3000 wiring rules to answer the wiring rules questions of the LET. There are two main ways of navigating through the wiring rules when answering these questions. One is to use the index at the back, and the second is to use the table of contents towards the start of the wiring rules book. My preferred way is to use the index section at the back. It’s quicker and it’s easier. Let’s take a look at an example. What is the minimum permissible size of an aluminum aerial conductor? Start by identifying keywords in the question. In this question, I think the keywords are aerial conductor, minimum size, and aluminum. Let’s look for aerial conductors first.

As we can see, it points us to conductor’s aerial. Let’s go there. In conductor’s aerial, there is minimum size which is pointing us to the clause 3.12.2.2. Let’s go there. As we can see, the closed 3.12.2.2 (a) is stating that, “Aluminum conductors installed as aerial conductors shall not be smaller than 16 millimeter squared.” One part of the answer is 16 millimeter squared, and the other part is the wiring rules clause 3.12.2.2 (a). It is important to quote the clause exactly where the answer is. Let’s look at an example where finding the information in the index is not as straightforward.

Are aluminum sheath conductors permitted to be used as a combined earthing and neutral conductor? Here, the keywords are, combined earthing and neutral conductor, and aluminum sheath conductors. First, let’s try the index. Here, your basic electrical knowledge will come in handy. Combined earthing and neutral is also called protective earthing and neutral or PEN. Let’s look for PEN conductors.

As we can see, it’s pointing us to conductors neutral, so let’s go there. Wow. That’s a lot of clauses to look through and the time is a luxury we don’t have during the LET. Let’s try the table of contents instead, to see if we can speed up the process. We can see that section three discusses wiring systems, and since we are talking about conductors, chances are we may find the answer here.

Looking through the section three of table of contents, we can see that 3.16 heading is Earth Sheet Return (ESR) System. This is quite close to what our keywords were, so let’s go there. It’s clearly stated here that only a copper sheath may be used as a combined earthing and neutral pen conductor. The first part of our answer to this question is no, and the second part is the wiring rules clause 3.16. Let’s quickly recap.

There are two main ways to navigate through the wiring rules to find the answers to LET wiring rules questions, using index or table of contents. I think it’s quicker to use the index if the opportunity exists. I hope all this made sense. If you need any clarification, please feel free to leave me a comment, and if you found this video useful, please like it. Thank you.