whistle Posted July 27, 2007 Share Posted July 27, 2007 So you are telling me that every galaxy i have ever installed is wrong and the manual is wrong?? And the 1000s i have serviced when working at //.Large National Installer.// are all wrong as the screen is earthed and not connected to 0V. Link to comment Share on other sites More sharing options...
Dandle Posted July 27, 2007 Share Posted July 27, 2007 The 0v line should be the same potential as earth. Infact you will probably find the 0v line is connected directly to earth on the PCB. Link to comment Share on other sites More sharing options...
alterEGO Posted July 27, 2007 Share Posted July 27, 2007 The 0v line should be the same potential as earth. Infact you will probably find the 0v line is connected directly to earth on the PCB. hmmm...............NO! the pcb is connected to the tranny, which does not require an earth to perform. Link to comment Share on other sites More sharing options...
Dandle Posted July 27, 2007 Share Posted July 27, 2007 hmmm...............NO! the pcb is connected to the tranny, which does not require an earth to perform. My P24 has an earth from the mains onto the tranny then connected onto the pcb as well(next to the two inputs from the transformer). Link to comment Share on other sites More sharing options...
Guest anguscanplay Posted July 28, 2007 Share Posted July 28, 2007 So you are telling me that every galaxy i have ever installed is wrong and the manual is wrong??And the 1000s i have serviced when working at //.Large National Installer.// are all wrong as the screen is earthed and not connected to 0V. nope cause you will have used belden ( mains rated ) cable The 0v line should be the same potential as earth. Infact you will probably find the 0v line is connected directly to earth on the PCB. My P24 has an earth from the mains onto the tranny then connected onto the pcb as well(next to the two inputs from the transformer). for a guy who didnt know how far to seperate his cable your suddenly very knowledgable hmm instead of fighting the members on this forum why not use that energy to go and connect your system correctly Angus ( yipee the bb is back and faster than ever) Link to comment Share on other sites More sharing options...
Dandle Posted July 28, 2007 Share Posted July 28, 2007 nope cause you will have used belden ( mains rated ) cablefor a guy who didnt know how far to seperate his cable your suddenly very knowledgable hmm instead of fighting the members on this forum why not use that energy to go and connect your system correctly Angus ( yipee the bb is back and faster than ever) I havent fought any members on this forum, just you and you started it. Im not the pro that knocks all the new guys and has now been shown up FACT after FACT. I asked about seperation as you mentioned about fire etc, I asked advice and you gave it. But you seem to get carried away and quiet a few of the things you have said have been misleading or wrong. I'm a licensed avoinic aircraft engineer and have a good knowledge of electronics and electrical installation(on a/c), for what I have done in my house I have sought advice of friends who are qualified in electrical and fire and security installations. Yet you keep shouting at me its wrong. Im sorry but I trust people who have seen my installation and are happy with it over you on another pc. Link to comment Share on other sites More sharing options...
amateurandy Posted July 28, 2007 Share Posted July 28, 2007 " its called Seperated Extra Low Voltage for a reason " connect the screen to 0v not earth If the system is definitely SELV then the following comments found on Wikipedia may clarify (but remember don't trust everything you read on t'internet folks ) (And ELV is up to 50V RMS AC or 120V DC) Note especially the comment re earth separation. IEC 61140 defines a SELV system as "an electrical system in which the voltage cannot exceed ELV under normal conditions, and under single-fault conditions, including earth faults in other circuits". A SELV circuit must have: protective-separation (i.e., double insulation, reinforced insulation, or protective screening) from all circuits other than SELV and PELV (i.e, all circuits that might carry higher voltages) simple separation from other SELV systems, from PELV systems and from earth (ground). The safety of a SELV circuit is provided by the extra-low voltage the low risk of accidental contact with a higher voltage; the lack of a return path through earth (ground) that electrical current could take in case of contact with a human body. The design of a SELV circuit typically involves an isolating transformer, guaranteed minimum distances between conductors, and electrical insulation barriers. The electrical connectors of SELV circuits should be designed such that they do not mate with connectors commonly used for non-SELV circuits. Link to comment Share on other sites More sharing options...
amateurandy Posted July 28, 2007 Share Posted July 28, 2007 If the system is definitely SELV then the following comments found on Wikipedia may clarify (but remember don't trust everything you read on t'internet folks )(And ELV is up to 50V RMS AC or 120V DC) Note especially the comment re earth separation. And to add to that: IEC 61140 defines a PELV system as "an electrical system in which the voltage cannot exceed ELV under normal conditions, and under single-fault conditions, except earth faults in other circuits". A PELV circuit only requires protective-separation from all circuits other than SELV and PELV (i.e, all circuits that might carry higher voltages), but it may have connections to other PELV systems and earth (ground). In contrast to a SELV circuit, a PELV circuit can have a protective earth (ground) connection ------------------------------------------------------ But who says, defines or requires that any particular alarm installation is SELV, PELV or whatever. Obviously the component and overall design have to be appropriate for each category ..... Link to comment Share on other sites More sharing options...
Guest anguscanplay Posted July 28, 2007 Share Posted July 28, 2007 as i said ages ago dandle - you do what you want , I do this for a living you dont yet you in fact started this with your post in this threaf about " it isnt as hard as the pro`s make out " ( i forget your exact wording ) when so obviously it is , youve got it wrong its up to you if you decide not to put it right there are dozens of new guys supported me recently - if you dont like the advice i give just use the " ignore " button within your user profile - but usually the advise i give is the best advice your going to see I aint interested in arguing with you for the fun of it , there comes a point where the o/p isnt listening to the advice they asked for because they just dont like what they are hearing ( always the same old story ) Angus Link to comment Share on other sites More sharing options...
alterEGO Posted July 28, 2007 Share Posted July 28, 2007 My P24 has an earth from the mains onto the tranny then connected onto the pcb as well(next to the two inputs from the transformer). good, but not all do or need to be. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.