Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Helpful Answer
  • Locked Locked
  • Replies 12 replies
  • Subscribers 33 subscribers
  • Views 1833 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

Mentor or discussion forum on IET 5th EDITION code of practice

sean chalmers

WHERE do I get LEARNING discussion topics and feedback as I would in a classroom format or from a college mentor on many QUESTIONS I have regarding 5th EDITION IET Code of Practice?? 

For example on Page 80 Table 10.6..  1.5 mm cable has a maximum current carrying capacity of 13 Amps.... YET online I am finding PAT engineers testing Industrial extension leads 1.5 mm having 16 Amps run through them and in BLACK cable with BLACK sodding 60309 connectors... EXTREMELY baffelling and not with an axe to grind and as a none electrician am taking the exam soon THINGS are NOT matching up to spec...I need clarification.. I need answers to many seemingly oddball stuff..

Another quick on:   Page 98-99  5th Edition IET..  If you want peeps to get confused this is it:  ES1 is equivalent to Class III ok... then ELV and SELV (no PELV and no FELV??) are WHAT.. class II? 

An exam Q will TRY an TRIP me up over Low Voltage and Extra Low Volts ok.. seemingly obvious YET online sources declare 0-1000 volts AC and 0-1500 volts DC as Low Volts yet another no no no its 120-1500 DC and 50-1000 AC

IF i take that second reference at FACE value on page 99 in the IET we see a table declaring ES2 at 120 volts DC 50 AC  what is that doiing sat right in the MIDDLE of that table??  and what is ES2?  its not clear and I am in mind

to class ES2 as CLASS II...... furthermore in SELV we see a sodding CP being available as basic protection in some cases?????????  Getting really strapped over this guys..

Parents
  • 0

    Might be useful if you could say which code of practice you're referring to (I believe the IET publish quite a few, on different electrical subjects), but chances are you're in the right place for a discussion (arguments are next door ... to misquote Monty Python).

    To clarify the clarification as it were, BS 7671 defines extra low voltage as not exceeding 50V AC or 120V ripple free DC, and low voltage as exceeding extra low voltage but no exceeding 1000V AC or 1500V DC between conductors, or 600V AC or 900V DC between a conductor an Earth. Above that is high voltage (p 44 of BS 7671). The definition often does get shortened for brevity, rather than clarity, and some sectors (e.g. transmission) tend to think of their bit as High Voltage and everything else as Low Voltage.

    I think the ES classifications have been adopted by the standards for some types of electrical equipment (e.g. AV & communication equipment) for shock protection in general. They do the same sort of job as Class I, Class II class III etc, but take a different approach (partly by limiting the energy, rather than just the voltage, available for a shock), so aren't directly equivalent. It all gets a bit messy when all sorts of wires come out of such equipment and back into the building and so other standard (e.g. BS 7671 apply as well). Others here may know much more about the details.

        - Andy.

Reply
  • 0

    Might be useful if you could say which code of practice you're referring to (I believe the IET publish quite a few, on different electrical subjects), but chances are you're in the right place for a discussion (arguments are next door ... to misquote Monty Python).

    To clarify the clarification as it were, BS 7671 defines extra low voltage as not exceeding 50V AC or 120V ripple free DC, and low voltage as exceeding extra low voltage but no exceeding 1000V AC or 1500V DC between conductors, or 600V AC or 900V DC between a conductor an Earth. Above that is high voltage (p 44 of BS 7671). The definition often does get shortened for brevity, rather than clarity, and some sectors (e.g. transmission) tend to think of their bit as High Voltage and everything else as Low Voltage.

    I think the ES classifications have been adopted by the standards for some types of electrical equipment (e.g. AV & communication equipment) for shock protection in general. They do the same sort of job as Class I, Class II class III etc, but take a different approach (partly by limiting the energy, rather than just the voltage, available for a shock), so aren't directly equivalent. It all gets a bit messy when all sorts of wires come out of such equipment and back into the building and so other standard (e.g. BS 7671 apply as well). Others here may know much more about the details.

        - Andy.

Children
  • 0 in reply to AJJewsbury

    Andy cheers bud for your advise... you just cemented in my mind regarding low and extra low just for personal and exam purposes I gues is important .. very important lol I got a Question to bounce back with if you don't mind... 1/  WHY "between conductors" and not ground? Is that the 3 phase business and balanced conductors phase and out of phase ??

    Yes it is for me as essentially a novice even with L3 and 17th Edition  back in 2014 but no actual experience... its MESSY.. I want to CRUSH this exam coming up this month and I know the exam will throw some "curved balls"  FACT..

    The 5th edition for example says 1.5 cable limited to 15 meters but I have seen mock or post exam questions referring to cable at 20 meters + or something like that and questioning my response.. questioning my understanding when all I want is simple THIS IS THIS and that is that.. anyways bud thanks for the help.. I do my best and well we will see if I am successful..

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines