P
philp
I have been trying to pass the written 2394 for a while now. The course that I am on is sadly lacking. I passed the 2395, but am having terrible trouble with the 2394. I have loads of questions, but not sure where to go for the answers...I've given up on my course. The following questions are just some of the many questions that I have. I would appreciate any help.
1) General Question :- I would love to get hold of pass papers with answers so that I can study them. After spending thousands on my course I am trying to find a source for as little cost as possible. It annoys me that C&G do not publish past papers (preferably with answers). Any recommended books? I feel fairly happy on single phase, but have trouble with three phase. I only intend to do occasional domestic, so three phase and industrial does not interest me. But I need to study them for the exam.
2) Initial Verification is for a new installation. Does that mean that you do not need to do safe and secure isolation since the distributor is not connected yet? So for continuity, IR, Polarity you do not need to do Secure isolation. I believe that you do need to do an insulation resistance test between Line and earth after the distributor is connected (because the main earth is only present when distributor connected for TN). Not sure about TT? GN3 tells you that you must connect the cpc to the earthing arrangement in order to do the test, hence this must be done after the distributor is connected!!??!! Should these tests now be done after the distributor is connected in which case you would need to do safe ans secure isolation?
3) Order of tests. I have read the following:-
I am having difficulty understanding the full meaning of this statement. Is it a no-no to connect the +500 volts red lead to the cpc...should the red lead always be connected to the live conductors? Basically it would mean that all extraneous metalwork would have the high voltage straight away without the low insulation resistance. Also, even though 500 volts have been put across the tester terminals...only if you touch a live conductor and the extraneous part will current flow...the fact that an extraneous part has 500 volts on it does not mean that current will flow through you if you touch it? Its got to go back through the tester!!! What about the exposed parts? Why is it now a requirement that the cpc is earthed/grounded through the distributor?
My answer to the insulation resistance after continuity would be that your not testing insulation resistance on the whole circuit...I'm a little confused about the statement above....Please put me out of my misery
Sorry for all the questions....
Thanks
1) General Question :- I would love to get hold of pass papers with answers so that I can study them. After spending thousands on my course I am trying to find a source for as little cost as possible. It annoys me that C&G do not publish past papers (preferably with answers). Any recommended books? I feel fairly happy on single phase, but have trouble with three phase. I only intend to do occasional domestic, so three phase and industrial does not interest me. But I need to study them for the exam.
2) Initial Verification is for a new installation. Does that mean that you do not need to do safe and secure isolation since the distributor is not connected yet? So for continuity, IR, Polarity you do not need to do Secure isolation. I believe that you do need to do an insulation resistance test between Line and earth after the distributor is connected (because the main earth is only present when distributor connected for TN). Not sure about TT? GN3 tells you that you must connect the cpc to the earthing arrangement in order to do the test, hence this must be done after the distributor is connected!!??!! Should these tests now be done after the distributor is connected in which case you would need to do safe ans secure isolation?
3) Order of tests. I have read the following:-
For example, it is of great importance that the continuity, and hence the effectiveness, of protective conductors is confirmed before the insulation resistance test is carried out. The high voltage used for insulation testing could appear on all extraneous metalwork associated with the installation in the event of an open-circuit protective conductor if insulation resistance is very low.
I am having difficulty understanding the full meaning of this statement. Is it a no-no to connect the +500 volts red lead to the cpc...should the red lead always be connected to the live conductors? Basically it would mean that all extraneous metalwork would have the high voltage straight away without the low insulation resistance. Also, even though 500 volts have been put across the tester terminals...only if you touch a live conductor and the extraneous part will current flow...the fact that an extraneous part has 500 volts on it does not mean that current will flow through you if you touch it? Its got to go back through the tester!!! What about the exposed parts? Why is it now a requirement that the cpc is earthed/grounded through the distributor?
My answer to the insulation resistance after continuity would be that your not testing insulation resistance on the whole circuit...I'm a little confused about the statement above....Please put me out of my misery
Sorry for all the questions....
Thanks