116 On Lightning Conductors. 



2nd. Insufficient elevation above the rest of the building. 

 In this case the building may be struck at points distant 

 from the conductor. A common case is that of a roof 50 or 

 100 feet long, with a conductor at one or both ends not rising 

 more than 5 feet above the ridge. 



3rd. Numerous joints breaking the metallic continuity of 

 the conductor. These joints may appear mechanically good, 

 but be very defective electrically, especially when old and 

 corroded. They impede the silent discharge, and increase 

 the risk, in the event of actual stroke, of the electricity 

 leaving the conductor and striking across to some other 

 metallic mass. 



4th. Insuificient sectional area. This is a most usual fault. 

 Should such conductors be actually struck, they would fuse 

 before the charge was carried off, leaving the remainder to 

 force its way to some other conducting body. Many of our 

 conductors are not more than one-third as large as they 

 ^^hould be. 



5th. Insulation. Instead of bringing the conductor into 

 ^he closest contact with the building, many persons carefully 

 insulate it. This in no way aids the conductor in fulfilling 

 its functions, while it greatly enhances the danger should 

 some other part of the building first receive the discharge. 



6th. Bad earth connection. This is a common and most 

 fatal defect. Owing to accidental damage, theft, or corrosion, 

 many conductors do not reach the ground at all^ but terminate 

 a few feet above. These are most dangerous. They induce 

 the discharge which otherwise would probably not have 

 taken place, and cause a violent manifestation of electric 

 energy at a place where it is likely to do much damage to 

 life or property. Such a conductor should be either properly 

 repaired or entirely removed. Further, some conductors 

 which apparently reach the earth are so terminated that the 

 resistance to the passage of electricity is greater than that of 

 some water or gas -pipe in the vicinity. In this case a lateral 

 discharge is likely to take place, with disastrous results, 

 damaging brickwork or masonry, fusing gas-pipes and setting 

 fire to the gas, or injuring or killing any person in the 

 vicinity. 



I do not wish to be an alarmist, but I feel it my duty to 

 point out the extremely unsatisfactory state of the vast 

 majority of lightning conductors in Melbourne, and to urge 

 that a general inspection and renovation should take place 

 under the direction of a competent electrician, who should 



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