Another question for Sparks please?


Postby Jeffmo » Wed Jun 20, 2007 8:22 pm

Hi Sparks , i have a ? which might crop up in my exam on monday and i just can't remember or grasp what formula or where i should gleam the information from . Wonder if you could help ? ...Heres an example :-
A 230 V 30 A RADIAL CIRCUIT IS PROTECTED BY A BS3036 DEVICE.IF THE VALUE OF PHASE EARTH LOOP IMPEDENCE FOR THE CIRCUIT IS 2.3OHMS,DISCONNECTION UNDER PHASE/EARTH FAULT CONDITION WILL OCCUR IN .....Thats the question format and i think the answer is 3 sec's but its how i get there that is the problem please advise as its starting to make me worry about the exam , which in theory shouldn't be a problem , its just one little thing makes me doubt myself , thats just me i want everything to be perfect and to do that i need to know what and why .Cheers Jeff
Jeffmo
Rank: Ganger
Progress to next rank:
35.3%
Posts: 103
Joined: Mon Apr 09, 2007 9:22 am

Sponsor

Simply Build It

Postby Jeffmo » Thu Jun 21, 2007 10:40 pm

[quote="Jeffmo"]Hi Sparks , i have a ? which might crop up in my exam on monday and i just can't remember or grasp what formula or where i should gleam the information from . Wonder if you could help ? ...Heres an example :-
A 230 V 30 A RADIAL CIRCUIT IS PROTECTED BY A BS3036 DEVICE.IF THE VALUE OF PHASE EARTH LOOP IMPEDENCE FOR THE CIRCUIT IS 2.3OHMS,DISCONNECTION UNDER PHASE/EARTH FAULT CONDITION WILL OCCUR IN .....Thats the question format and i think the answer is 3 sec's but its how i get there that is the problem please advise as its starting to make me worry about the exam , which in theory shouldn't be a problem , its just one little thing makes me doubt myself , thats just me i want everything to be perfect and to do that i need to know what and why .Cheers Jeff[/quote]
Jeffmo
Rank: Ganger
Progress to next rank:
35.3%
Posts: 103
Joined: Mon Apr 09, 2007 9:22 am

Postby sparx » Thu Jun 21, 2007 10:50 pm

hi jeffmo, very late, books in van but i think tables 41b1/2 give max values for 0.4 or 5.0 sec disconnection times, these being only options if i understand ?
BCNU
SPARX
sparx
Rank: Project Manager
Posts: 2166
Joined: Wed Mar 21, 2007 8:33 pm
Location: The fifth continent.

Display posts from previous
Sort by
Order by



  • DIY How to Project Guides

  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!



 


  • Related Topics