Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 45 replies
  • Subscribers 32 subscribers
  • Views 4042 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Cattle deaths

lyledunn
Some 10 prize bullocks died in quick succession whilst housed over winter in a cattle shed. The government vet was unable to reach a conclusion on cause but apparently does not discount electric shock as an indirect cause. 

The shed comprises steel columns and trusses with corrugated iron sheeting over. The floor comprises re-Inforced concrete slats over the slurry tank. The pens have steel barriers supported by steel posts all of which are heavily corroded but still making contact with other albeit fortuitously.

The earthing system is TT with the shed steelwork on its own providing a substantially low impedance of 5 ohms using a loop tester. A 100mA RCD protects the rather ropey lighting circuits.defccf32df3c757507a0db6ad0a35f87-huge-a5af3537-8eae-4a3c-9126-68fa60b61ac7.jpg

whilst the floor could be wet, I can’t conceive how a voltage difference could be established even if the steelwork was at 230v

Parents
  • 0
    Andy, yes I did say that I found it difficult to conceive that a voltage gradient of a detrimental order for cattle would appear for long durations but I was factoring in the proper function of the upfront 100mA RCD. There are no downstream RCDs. If the fault current was just below the tripping current of the RCD, with a Ra of approximately  5ohms we are looking at voltage of no concern. However, if we assume that the RCD failed to operate (although it responded immediately to test and the farmer reported that it operated occasionally), then we are left with the fuse to provide fault protection. Whilst there was nothing other than minimal lighting in the shed in question, an adjoining shed did have higher rated circuits. By the way, the general installation could only be described as dangerously sub-standard.
Reply
  • 0
    Andy, yes I did say that I found it difficult to conceive that a voltage gradient of a detrimental order for cattle would appear for long durations but I was factoring in the proper function of the upfront 100mA RCD. There are no downstream RCDs. If the fault current was just below the tripping current of the RCD, with a Ra of approximately  5ohms we are looking at voltage of no concern. However, if we assume that the RCD failed to operate (although it responded immediately to test and the farmer reported that it operated occasionally), then we are left with the fuse to provide fault protection. Whilst there was nothing other than minimal lighting in the shed in question, an adjoining shed did have higher rated circuits. By the way, the general installation could only be described as dangerously sub-standard.
Children
No Data

Community Rules & Guidelines