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Russell Bull
11/08/06 17:06
Read: 675 times

#127618 - Direct Hits
Responding to: Erik Malund's previous message
If you get a direct hit from lightning, all bets are off. One site in Malaysia had a hole blown in a brick wall! The PC inside did not survive!

However, most damage is caused by close lightning strikes. Becuase of the large electromagnetic pulse, anything conductive acts like a turn in a transformer. Therefore, you need to protect incoming wires with a variety of strategies depending on the signal and the anticipated severity.Sheilded cables with the shield terminated to earth at both ends is a start. Movs, transzorbs,GDTs are also used to protect the circuits themselves. Buildings will normally have a thick copper bar running around the roof then down to ground for lightning protection - you want to tap into this for your lightning earth return. Every earth conductor has to be large for any effect - small conductors are next to useless.

You can do a lot to minimise damage from lightning, but don't expect to completely cure it!

List of 20 messages in thread
Lightning protection      Ap Charles      11/08/06 06:17      
   there is much to this      Erik Malund      11/08/06 06:19      
      Lightning protection      Ap Charles      11/08/06 06:24      
         so doesa EMI      Erik Malund      11/08/06 06:36      
            Mr. Faraday knew how...      Kai Klaas      11/08/06 08:13      
               THICK metal      Steve M. Taylor      11/08/06 09:45      
            Direct Hits      Russell Bull      11/08/06 17:06      
               Keep it out of the encosure!      Kai Klaas      11/08/06 20:08      
                  My pplication      Ap Charles      11/08/06 23:52      
                     Details?      Kai Klaas      11/11/06 08:33      
               I disagree      Erik Malund      11/09/06 06:07      
                  No, no...      Kai Klaas      11/09/06 20:32      
                     Disconnecting the shield at one end of the cables      Ap Charles      11/09/06 23:44      
                        a) and b)      Erik Malund      11/10/06 06:05      
                           Yes, crossed opinions...      Kai Klaas      11/10/06 09:18      
                              and the twain shall never meet      Erik Malund      11/10/06 10:52      
                        the Shield      Andy Peters      11/10/06 14:55      
                           The RS485 signal lines is galvanically...........      Ap Charles      11/10/06 23:01      
                              GND of RS485 bus, PROFIBUS      Kai Klaas      11/11/06 08:27      
   If you get this close        Jez Smith      11/09/06 01:28      

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