So far we've looked at SANS 10142-1's cover, introductory pages, table of changes, foreword and introduction and discovered that we should not underestimate the importance of the ‘uninteresting' pages at the beginning of the standard, as these have an impact on the way an electrical installation is approached.

Now we'll look at some of the more ‘technical' sections and the next few columns will concentrate on the ‘hands on' approach to sections of SANS 10142-1. This will hopefully help you to better understand the rest of the standard and help you to find information quicker without having to endlessly page through the standard.

Towards the end of the contents pages you will find other informative lists of ‘annexes', ‘tables, ‘figures' and ‘certificates'.
In the annexes section you will find information relating to, for example:

• An example for assessing the estimated load for residential type installations - what size of supply and/or main breaker is required for an installation or circuit. I am aware of at least one Supply Authority that required this calculation be included as part of the ‘Commencement of Work' notification. 
• Annexure 1 (a requirement of Act 85 of 1993 the Occupational Health and Safety Act) in days gone by and now known as Annexure 4. Commencement of Work? Yes, how else would the Supply Authority know what you will be adding to their electricity supply network? This little document is also the major cause of minor (major?) wars between electrical contractor and client. Why? Because when the contractor asks the Supply Authority to switch on the power because he's finished his job, the Supply Authority quite rightly asks, "You want what... when?" 
• How to determine the conduit size you would require for a given quantity of single core cables like maybe 2 x 4mm2 and 4 x 2.5mm2 cables. 
• The explanation of what ‘IP numbers' mean. 
• The explanation of the various electrical supply systems, such as ‘TN-C-S', ‘TN-S' and ‘TT'. 
• And what the IEC symbols associated with switchgear look like.

Interesting? You bet! I'm sure may of you have asked the question: "How many cables can I legally accommodate in a conduit or can I just stuff as many as possible into the pipe?"

Next, you will find lists of ‘tables'. These tables summarise important information such as:

• Applicable Standards. This will, for instance, tell you that copper busbars have to comply with SANS 1195 and that flexible cords (the stuff you use for extension leads) should comply with VC 8006a. 
• Table 4.3 presents you with an easy to understand list of where to find information pertaining to ‘notices, labels and rating plates' such as the labelling required for socket outlets at caravan parks, mobile homes and marinas. 
• Table 6's sub tables provide facts relating to the ‘current carrying capacity' and ‘voltage drop per ampere per meter' for cables. This information is vital when designing an electrical installation. 
• A table's recommendations that get trashed on a virtual daily basis this ‘Table F.1 - Minimum radius of curvature of cables'. This table illustrates the minimum radius to which a cable (single core, multi core, armoured and un-armoured) can/should be bent. And read as I might, I can never seem to find the words "4lb hammer"! Yes, that thing that makes a stubborn cable go around a 90 degree corner on a concrete pillar in no time flat!

What this table wants me to do, is use the 4lb hammer to break away the sharp edge of the concrete pillar instead and let the cable take a nice slow bend around it. You hit a cable with anything to make it bend more than its natural radius, and you have just secured a future repair job for yourself because the cable will blow at that point, believe me.

Then there is the list of ‘figures': These figures include illustrations of the zones in bathrooms, very often the source of heated discussions between client and contractor as to the legality of the placement of appliances and/or the application of standards.

You will also find a schematic diagram for a change-over switch connection where UPS power feeds into a section of the main distribution board.

Last but not least, we are given the listing of the relevant certificates that form part of SANS 10142-1.
Prior to Amendment 7, these certificates where known as Certificates of Compliance. As from Amendment 7 onwards these same forms will be known as:

• Test report for all electrical installations.
• Additional test report for a medical location.
• Additional test report for a hazardous location.

We have only looked at a few of the annexes, tables, figures and all the certificates; but hopefully this superficial look has inspired you to look at the relevant sections more closely and regularly and, in so doing, making your daily working life a little easier.