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JUST SHUT DOWN A 10 Story Office Building with a 20A Circuit

3502 Views 35 Replies 27 Participants Last post by  brian john
Short circuit on a 20A lighting circuit and it shut down the whole building!!
What would have caused this to happen? Why did none of the other breakers in the series trip?
Guessing the trip settings on the existing main were dialed down way too low?

Needless to say, my guys had a stressful morning/:biggrin:
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· Hackenschmidt
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14,392 Posts
I agree a coordinated study may not have been done and the setting was too low on the main.

I took out a 400 amp breaker and a 7 pole contactor with a short on a 20 amp circuit at an IBM plant in ny
LOL at an IBM facility!?! That's priceless, they were known for running a ridiculously tight ship and letting you know about it constantly. I wonder how many of their engineers had eyes on this and it still made it past the goalie...
 

· Premium Member
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20,178 Posts
Short circuit on a 20A lighting circuit and it shut down the whole building!!
What would have caused this to happen? Why did none of the other breakers in the series trip?
Guessing the trip settings on the existing main were dialed down way too low?

Needless to say, my guys had a stressful morning/:biggrin:
They certainly have a coordination issue.
My conversations begin with something like:
"I want this event to be my responsibility but, this simple lighting short has exposed a deficiency in your circuit breaker coordination all the way to the main breaker. This will keep happening until it gets resolved"
Would you like us to commission a coordination study and present you with the remediation plan or do you have an engineer that can help you with it?
 
1 - 20 of 36 Posts
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