Fried Equipment in a Chicken House

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R&T Jimmy

Member
Location
Washington Ga USA
Occupation
Licensed Electrical Contractor and Building Official for local City/ County
Forgive me for the length of this thread. I am looking into an issue at a broiler farm. 4 enclosures 75 wide by 750 long. Since they were commissioned they have all had trouble with burning up computer control boards, not in the same enclosure every time, and not the same board every time. Very random when it happens, but mostly after a thunderstorm. The service(s) are identical but fed from different pad mount transformers. From xformer 2 sets of 350 al conductors one each into a pair of 400 amp disconnects. I know this is light but that is the POCO wire so they put in what they want. From the disco there are parallel two 4/0 AL one 2/0 AL and one 6awg copper ground into each of 2 400 amp automatic transfer switches. Also out of each disco is a #2 copper going out to a ground rod. From each ATS is the same 4 wire configuration going into a 400 amp distribution panel. Out of this panel two feeders each from a 200 amp breaker go to one panel in each of 2 enclosures. Neutrals and grounds are separated in each of these panels and each panel has a #4 copper going outside to its own ground rod. This is one side, the second side mirrors it. All the equipment in the service is bonded together and to all six ground rods. The rods are 30 feet apart at a maximum an at minimum 6 feet apart. The ground rods at the enclosures are not bonded together except at the service equipment, same with the rods from the disconnects. I first thought it was a grounding/ bonding issue, but now I do not know. Any ideas would be appreciated.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
Occupation
Field coordinator/ technical support
How many generators? Does the automatic transferswitch switch the neutral? If so, is the neutral bonded at the generator? Any TVSS’s on the service?
 

R&T Jimmy

Member
Location
Washington Ga USA
Occupation
Licensed Electrical Contractor and Building Official for local City/ County
1 generator for each pair of enclosures. The ATS has a solid neutral in it so no switching. Neutral is not bonded at the generator, there is a separate EGC from the genset to each transfer switch.
 

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
Are these computer control boards connected by wiring to sensors, external controls, relays, etc. that could be picking up some transient voltages and causing the boards to fail?
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Sounds like you may need a good surge suppressor to control voltage spikes. If the farm has a high iron content in the soil that could make it more prone to lightning- at least the power company around here stated that.

I would definitely go with the suppressor
 

hillbilly1

Senior Member
Location
Atlanta,Ga
Occupation
Field coordinator/ technical support
Are these computer control boards connected by wiring to sensors, external controls, relays, etc. that could be picking up some transient voltages and causing the boards to fail?
Maybe feed bin level sensors? Since they are usually tall, may be attracting transients since the op said it seems to happen most often during storms. Maybe bond the bins to the grounding electrode, and possibly a couple of more rods close to the bins.
 

R&T Jimmy

Member
Location
Washington Ga USA
Occupation
Licensed Electrical Contractor and Building Official for local City/ County
I had not thought of the feed bins, I will look into that. The boards are connected to sensors, fan motors feed bin motors etc.
 
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