480volt 600amp service question

[Ed Carr]

We will be installing a new service at a small factory.
In another thread I saw a reference to GFI protection.
The thread under "safety" concerned the total failure
of some switch gear where the ground fault protection
had been turned off.What are they referring to?
Can someone explain what GF protection consists of
in a service such as I am doing?

Thanks, Ed












what

 

[charlie b]

I don't have my NEC handy, so someone will have to correct anything I remember incorrectly. But from what I recall it would not apply to your installation. The topic is Ground Fault Protection for Equipment, and is nothing at all like the Ground Fault Circuit Interruption (GFCI) requirements for such things as 120 volt receptacle outlets. It is generally installed on service equipment only (not on downstream distribution panels), and is required for services rated 1000 amps or higher. It protects the service equipment from a fault to planet Earth, as opposed to a fault from phase to phase, or from phase to neutral. It has setpoints on the order of hundreds of amps. That's about all I want to risk saying, without a reference at hand.

 

[Ed Carr]

Charlie & others ...in the thread I'm referring to quogueelectric
referred to a 600 amp service he witnessed self-destruct.
The statement was "it was an older service with no ground
fault protection".That got me wondering if this was something
I was missing.

Ed

 

[electricalperson]

i never installed a 600 amp service with GFPE. its required for services 1000 amps or more 230.95

 

[iwire]

Charlie & others ...in the thread I'm referring to quogueelectric
referred to a 600 amp service he witnessed self-destruct.
The statement was "it was an older service with no ground
fault protection".That got me wondering if this was something
I was missing.

Ed

Ed, I mean no offense to quogueelectric but we do not know what the cause of the failure he saw was.

As far as what the NEC requires see 230.95 which applies to service over 1000 amps and more then 150 volts to ground.

IMO you should be more concerned with "110.9 Interrupting Rating" that requires that your equipment can withstand the available fault current. If you do not follow this requirement and a fault happens your main breaker could literally blow up.

Have you gotten the available fault current from the utility?

I hope you did this before you priced the job because if the fault current is high the correctly rated equipment will be much more expensive.

 

[zog]

Have you gotten the available fault current from the utility?

I hope you did this before you priced the job because if the fault current is high the correctly rated equipment will be much more expensive.

I get calls like this every day, someone has bought the breakers for the job and then found out the fault current exceeded the AIC, they get sticker shock when they fond out the difference in prices for a higher AIC breaker.