Breaker ground settings for industrial systems
Breaker ground settings for industrial systems
(OP)
What methodology is used to set the feeder breaker ground settings in industrial places?
SC calculations?
I have the phase settings for the breakers.
SC calculations?
I have the phase settings for the breakers.






RE: Breaker ground settings for industrial systems
Rafiq Bulsara
http://www.srengineersct.com
RE: Breaker ground settings for industrial systems
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If we learn from our mistakes I'm getting a great education!
RE: Breaker ground settings for industrial systems
Given that, as an EPC, we seldom put GF on 480V motors. Ground faults on any motor over about 50 HP does trip the whole MCC because it is too dangerous to set the breaker's GF protection pickup or time delay any higher. However, we try to get the client's to go with a high resistance grounded system with a good maintenance staff (like you) so faults can be quickly located without anything tripping.
On IEC projects, we usually include GF protection on individual motors, just not on yours.
I accept the lashes.
RE: Breaker ground settings for industrial systems
RE: Breaker ground settings for industrial systems
British code prevents use of anything other than a solidly earthed LV system except under very specific circumstances. Isolated or impedance-earthed systems are very rare over here.
I'm sure a lot of the problems in that plant had their roots in a weak spec and a construction program where doing things quickly was considered more important than doing them right, and all being masterminded by an organisation which made the mafia appear honourable and trustworthy.
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If we learn from our mistakes I'm getting a great education!